@article { ISI:000236923400014, title = {Catalytic transesterification of beta-ketoesters with zeolite H-FER under solvent free conditions}, journal = {Arkivoc}, volume = {13}, number = {13}, year = {2005}, month = {MAY}, pages = {162-168}, publisher = {ARKAT USA INC}, type = {Article}, address = {C/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USA}, abstract = {

Zeolite H-FER catalyzes the transesterification of beta-ketoesters with variety of alcohols under solvent-less condition in excellent yields. The catalyst can be reused without any loss of activity.

}, keywords = {ferrierite, transesterification, zeolite}, issn = {1424-6376}, author = {Chavan, Subhash P. and Pasupathy, K. and Shengule, S. and Shinde, V. and Anand, R.} } @article { ISI:000227246800051, title = {Diastereoselective amidoalkylation of (3S,7aR)-6-benzyl-7-hydroxy-3-phenyltetra-hydro-5H-imidazo[1,5-c][1, 3]thiazol-5-one : a short and highly efficient synthesis of (+)-biotin}, journal = {Journal of Organic Chemistry}, volume = {70}, number = {5}, year = {2005}, month = {MAR}, pages = {1901-1903}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A short and highly efficient synthesis of W-biotin in 10 steps with 20\% overall yield has been achieved from L-cysteine involving amidoalkylation of hydroxy imidazothiazolone 4 via an acyliminium ion intermediate to furnish C-7-substituted imidazothiazolones 5b as the key step.

}, issn = {0022-3263}, doi = {10.1021/jo0488107}, author = {Chavan, Subhash P. and Chittiboyina, A. G. and Ravindranathan, T. and Kamat, Subhash K. and Kalkote, Uttam R.} } @article { ISI:000226332600017, title = {Efficient stereoselective synthesis of (2S,4S,5R)-(-)- and (2R,4R,5S)-(+)-bulgecinine}, journal = {Tetrahedron Letters}, volume = {46}, number = {3}, year = {2005}, month = {JAN}, pages = {439-441}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A short synthetic route to (-)-and (+)-bulgecinine, the amino acid moiety of the bulgecins was achieved from the readily available nonchiral pool starting material cis-2-butene-1,4-diol in which a Claisen orthoester rearrangement and a Sharpless asymmetric dihydroxylation were used as the key steps. (C) 2004 Elsevier Ltd. All rights reserved.

}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2004.11.101}, author = {Chavan, Subhash P. and Praveen, C. and Sharma, P. and Kalkote, Uttam R.} } @article { ISI:000228951700012, title = {Facile regioselective decomposition of tosylhydrazones: an application towards the synthesis of alpha-lipoic acid}, journal = {Synlett}, number = {7}, year = {2005}, month = {MAY}, pages = {1129-1132}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A facile regioselective decomposition of tosylhydrazones using NaOH as a base in refluxing isopropyl alcohol is described. This finding has been Successfully applied towards the synthesis of (\±)-α-lipoic acid (1).

}, keywords = {alpha-lipoic acid, Olefins, Regioselectivity, tosylhydrazones}, issn = {0936-5214}, doi = {10.1055/s-2005-865217}, author = {Chavan, Subhash P. and Kale, R. R. and Pasupathy, K.} } @article { ISI:000228147400027, title = {First enantiospecific synthesis of (+)-beta-herbertenol}, journal = {Tetrahedron}, volume = {61}, number = {15}, year = {2005}, month = {APR}, pages = {3873-3879}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The first enantiospecific synthesis of (+)-beta-herbertenol, from naturally occurring R-(+)-citronellal, employing Taber{\textquoteright}s diazo decomposition protocol as the key step, is described. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {citronellal, diazo decomposition, enantiospecific}, issn = {0040-4020}, doi = {10.1016/j.tet.2005.01.050}, author = {Chavan, Subhash P. and Thakkar, M. and Kharul, Rajendra K. and Pathak, A. B. and Bhosekar, Gaurav V. and Bhadbhade, Mohan M.} } @article { ISI:000228267300014, title = {Simple, concise, stereocontrolled synthesis of (8E,10Z)-pentadecadien-1-ol acetate}, journal = {Synthetic Communications}, volume = {35}, number = {7}, year = {2005}, month = {AUG}, pages = {987-994}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

A simple, concise, and stereocontrolled synthesis of (8E, 10Z)-pentadecadien-l -ol acetate involving a Cadiot-Chodkiewicz reaction as the key step is described.

}, keywords = {acetate, Acrobasis vaccini, Cadiot-Chodkiewicz reaction, diacetylene, Pheromone}, issn = {0039-7911}, doi = {10.1081/SCC-200051715}, author = {Chavan, Subhash P. and Kharul, Rajendra K. and Kamat, Subhash K. and Kalkote, Uttam R. and Kale, R. R.} } @article { ISI:000229376400013, title = {Simplistic expedient and practical synthesis of (+/-)-alpha-lipoic acid}, journal = {Synthesis-Stuttgart}, number = {8}, year = {2005}, month = {MAY}, pages = {1297-1300}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Synthesis of a-lipoic acid has been achieved by a simple sequence of reactions. The synthesis highlights the use of alpha-chloroesters in a Reformatsky reaction. The intermediate keto acid is an intermediate from which both isomers of lipoic acid can be prepared.

}, keywords = {alpha-chloroesters, alpha-lipoic acid, Ozonolysis, Reformatsky reaction}, issn = {0039-7881}, doi = {10.1055/s-2005-861867}, author = {Chavan, Subhash P. and Shivsankar, K. and Pasupathy, K.} } @article { ISI:000227411400039, title = {Stereoselective synthesis of (-)-microcarpalide}, journal = {Tetrahedron Letters}, volume = {46}, number = {11}, year = {2005}, month = {MAR}, pages = {1939-1941}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A highly convergent and efficient synthesis of (-)-microcarpalide, a 10-membered lactone displaying remarkable microfilament disrupting activity is described. Ring-closing metathesis and Sharpless asymmetric dihydroxylations are the key steps. Our strategy highlights the application of novel hydroxy lactone precursors for the stereoselective synthesis of (-)-microcarpalide. (C) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {4-diol, cis-2-butene-1, Claisen ortho ester rearrangement, microcarpalide, Ring-closing metathesis, sharpless asymmetric dihydroxylation}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2005.01.052}, author = {Chavan, Subhash P. and Praveen, C.} } @article { ISI:000228575900018, title = {Synthesis of (+)-camptothecin}, journal = {Arkivoc}, volume = {2005}, number = {3}, year = {2005}, month = {JAN}, pages = {165-169}, publisher = {ARKAT USA INC}, address = {C/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USA}, abstract = {

A synthesis of optically pure camptothecin was achieved in 4 steps from previously reported aldehyde employing Sharpless asymmetric dihydroxylation as the key step.

}, keywords = {Anticancer, camptothecin, sharpless asymmetric dihydroxylation}, doi = {10.3998/ark.5550190.0006.318}, author = {Chavan, Subhash P. and Venkatraman, M. S.} } @article { ISI:000231782100007, title = {Unusual stereochemical outcome of radical cyclization: synthesis of (+)-biotin}, journal = {Tetrahedron}, volume = {61}, number = {39}, year = {2005}, month = {SEP}, pages = {9273-9280}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An enantioselective synthesis of (+)-biotin 1 starting from naturally available cysteine is described. The key steps are the unusual stereochemical outcome of radical cyclization of compound 10 to prepare 5,5-fused system 11, and the introduction of C4-sidechain at C-6 in 13 via a Grignard reaction. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {biotin, exocyclization, radical cyclization}, issn = {0040-4020}, doi = {10.1016/j.tet.2005.07.070}, author = {Chavan, Subhash P. and Chittiboyina, A. G. and Ramakrishna, G. and Tejwani, R. B. and Ravindranathan, T. and Kamat, Subhash K. and Rai, B. and Sivadasan, L. and Balakrishnan, K. and Ramalingam, S. and Deshpande, V. H.} } @article { ISI:000241755300045, title = {First enantiospecific synthesis of (-)-parvifoline and (-)-curcuquinone}, journal = {Journal of Organic Chemistry}, volume = {71}, number = {23}, year = {2006}, month = {NOV}, pages = {8986-8988}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The first enantiospecific synthesis of (-)-parvifoline, employing ring-closing metathesis as the key step, and (-)-curcuquinone from naturally occurring (R)-(+)-citronellal is described.

}, issn = {0022-3263}, doi = {10.1021/jo061730d}, author = {Chavan, Subhash P. and Thakkar, Mahesh and Jogdand, Ganesh F. and Kalkote, Uttam R.} } @article { ISI:000242873400029, title = {Ring closing metathesis approach to the indole alkaloid mitralactonine}, journal = {Tetrahedron Letters}, volume = {47}, number = {52}, year = {2006}, month = {DEC}, pages = {9301-9303}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient utilisation of RCM leading to a convenient synthesis of a pentacyclic indole alkaloid is described. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {corynanthe type alkaloid, Dihydroxylation, mitralactonine, RCM, Swern oxidation}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2006.10.106}, author = {Chavan, Subhash P. and Sharma, Pallavi and Sivappa, R. and Kalkote, Uttam R.} } @article { ISI:000249894100012, title = {Convenient formal synthesis of (+/-)-paroxetine}, journal = {Synthetic Communications}, volume = {37}, number = {18}, year = {2007}, month = {SEP}, pages = {3143-3149}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

A formal total synthesis of antidepressant (+/-)-paroxetine employing a solvent-free Heck reaction is disclosed.

}, keywords = {antidepressants, carbamate, electrophile, Heck reaction, piperidines}, issn = {0039-7911}, doi = {10.1080/00397910701545130}, author = {Chavan, Subhash P. and Khobragade, Dushant A. and Pathak, Ashok B. and Kalkote, Uttam R.} } @article { ISI:000252219700011, title = {Efficient and practical total synthesis of (+/-)-alpha-cuparenone}, journal = {Synthesis-Stuttgart }, number = {24}, year = {2007}, month = {DEC}, pages = {3827-3830}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A one-pot cyclopentannulation approach as the key step for the total synthesis of (+/-)-alpha-cuparenone is described.

}, keywords = {Alkylation, annulation, hydroboration-oxidation, reduction}, issn = {0039-7881}, doi = {10.1055/s-2007-990899}, author = {Chavan, Subhash P. and Dhawane, Abasaheb N. and Kalkote, Uttam R.} } @article { ISI:000243819800014, title = {Facile total synthesis of (+/-)-alpha-cuparenone employing diallylation and RCM as key steps}, journal = {Tetrahedron Letter}, volume = {48}, number = {6}, year = {2007}, month = {FEB}, pages = {965-966}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A short and concise total synthesis of alpha-cuparenone employing one-pot diallylation and RCM as the key steps is described. (c) 2006 Elsevier Ltd. All rights reserved.

}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2006.12.023}, author = {Chavan, Subhash P. and Dhawane, Abasaheb N. and Kalkote, Uttam R.} } @article { ISI:000243704000028, title = {First enantiospecific synthesis of (-)-heritol: absolute configuration determination}, journal = {Tetrahedron Letters}, volume = {48}, number = {4}, year = {2007}, month = {JAN}, pages = {643-646}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The first enantiospecific synthesis of (-)-heritol, from naturally occurring (R)-(+)-citronellal and confirmation of its absolute configuration, is described. (c) 2006 Elsevier Ltd. All rights reserved.

}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2006.11.123}, author = {Chavan, Subhash P. and Thakkar, Mahesh and Kalkote, Uttam R.} } @article { ISI:000248145900007, title = {MgBr2-mediated ionic Diels-Alder reaction of acetals of alpha,beta-unsaturated aldehydes and ketones with 1,3-dienes}, journal = {Synthetic Communications}, volume = {37}, number = {14}, year = {2007}, month = {JUL}, pages = {2337-2343}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

A facile, mild, and efficient methodology for the ionic Diels-Alder reaction of acetals of alpha,beta-unsaturated ketones and aldehydes as dienophiles with various 1,3- dienes employing MgBr2 as the Lewis acid catalyst to furnish corresponding Diels-Alder adducts at ambient temperature is described.

}, keywords = {acetals, Catalysts, Diels-Alder reactions, dienes}, issn = {0039-7911}, doi = {10.1080/00397910701410814}, author = {Chavan, Subhash P. and Ethiraj, Krishna S. and Dantale, Shubhada W.} } @article { ISI:000244257400014, title = {Practical and facile approach towards indole alkaloids: (-)-mitralactonine}, journal = {Synlett}, number = {1}, year = {2007}, month = {JAN}, pages = {79-82}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

An efficient approach to (-)-mitralactonine using Pictet-Spengler cyclisation with a highly functionalised masked aldehyde is described. Sharpless asymmetric dihydroxylation (SAD) is utilised to introduce chirality in the key substrate.

}, keywords = {alkaloids, asymmetric, cyclisations, dihydroxylations, thioacetats}, issn = {0936-5214}, doi = {10.1055/s-2006-958434}, author = {Chavan, Subhash P. and Sharma, Pallavi and Sivappa, Rasapalli and Kalkote, Uttam R.} } @article { ISI:000249627100033, title = {Practical formal synthesis of camptothecin}, journal = {Tetrahedron Letter}, volume = {48}, number = {37}, year = {2007}, month = {SEP}, pages = {6561-6563}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The synthesis of the DE ring of camptothecin using simple and inexpensive starting materials, employing an addition elimination reaction and selective esterification of an aliphatic carboxylic acid as key steps is described. (C) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {alkaloid, Anticancer, camptothecin, Natural product}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2007.07.017}, author = {Chavan, Subhash P. and Pathak, Ashok B. and Kalkote, Uttam R.} } @article { ISI:000252029800002, title = {Practical synthesis of (+/-)-venlafaxine}, journal = {Synthetic Communications}, volume = {37}, number = {22-24}, year = {2007}, month = {NOV}, pages = {3901-3906}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

A practical total synthesis of antidepressant (+/-)-venlafaxine is disclosed.

}, keywords = {antidepressant, Grignard reaction, Michael addition}, issn = {0039-7911}, doi = {10.1080/00397910701572266}, author = {Chavan, Subhash P. and Khobragade, Dushant A. and Thakkar, Mahesh and Kalkote, Uttam R.} } @article { ISI:000252029800038, title = {Short and efficient synthesis of rubrolide E}, journal = {Synthetic Communications}, volume = {37}, number = {22-24}, year = {2007}, month = {DEC}, pages = {4253-4263}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

Short and efficient synthesis of rubrolide E from commercially available 4-methoxyacetophenone, employing ring-closing metathesis, Knoevenagel condensation, and Reformatsky reactions, are the key steps are described.

}, keywords = {antibiotics, antitumor, Epoxide, Natural products, Total synthesis}, issn = {0039-7911}, doi = {10.1080/00397910701575665}, author = {Chavan, Subhash P. and Pathak, Ashok B. and Pandey, Ankur and Kalkote, Uttam R.} } @article { ISI:000250836500003, title = {Total synthesis of (+)-camptothecin via an intramolecular palladium-catalyzed cyclization strategy}, journal = {Synlett}, number = {17}, year = {2007}, month = {OCT}, pages = {2635-2638}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

The novel cascade intramolecular Pd-catalyzed cyclization followed by aromatization for the construction Of D ring of (+)-camptothecin as a key step is demonstrated.

}, keywords = {alkaloids, antitumor, cyclizations, Natural products, Palladium}, issn = {0936-5214}, doi = {10.1055/s-2007-991054}, author = {Chavan, Subhash P. and Pathak, Ashok B. and Kalkote, Uttam R.} } @article { ISI:000247620500052, title = {Total synthesis of pulchellalactam via an RCM strategy}, journal = {Synthetic Communications}, volume = {37}, number = {7-9}, year = {2007}, month = {MAY}, pages = {1503-1510}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

Total synthesis of (Z) pulchellalactam, a CD protein tyrosine phosphatase inhibitor, from commercially available methallyl chloride employing ring-closure metathesis (RCM) as a key step is described.

}, keywords = {alkaloid, Natural products, pulchellalactam, RCM, Total synthesis}, issn = {0039-7911}, doi = {10.1080/00397910701229131}, author = {Chavan, Subhash P. and Pathak, Ashok B. and Dhawane, Abasaheb N. and Kalkote, Uttam R.} } @article { ISI:000271775108158, title = {ORGN 511-Total synthesis of 7-chloro-10-methoxycamptothecin: an important synthon for commercially important derivatives of camptothecin}, journal = {Abstracts of Papers of the American Chemical Society}, volume = {235}, year = {2008}, note = {235th American-Chemical-Society National Meeting, New Orleans, LA, APR 06-10, 2008}, month = {APR}, publisher = {Amer Chem Soc}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, issn = {0065-7727}, author = {Sharma, Anil and Chavan, Subhash P. and Venkatraman, M. S.} } @article { ISI:000261466800007, title = {Tandem aza-michael-condensation-aldol cyclization reaction: approach to the construction of DE synthon of (+/-)-camptothecin}, journal = {Synlett}, number = {18}, year = {2008}, month = {NOV}, pages = {2781-2784}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

An efficient synthesis of the DE ring of camptothecin, employing a Reformatsky and a tandem one-pot, three-step transformation involving aza-Michael reaction, condensation with ethyl malonyl chloride followed by intramolecular {\textquoteleft}aldol{\textquoteright} reaction to furnish the dihydropyridone derivative from commercially available starting materials, has been achieved.

}, keywords = {Aldol cyclizations, alkaloids, antitumor, Natural products, Reformatsky reaction}, issn = {0936-5214}, doi = {10.1055/s-0028-1083539}, author = {Chavan, Subhash P. and Dhawane, Abasaheb N. and Kalkote, Uttam R.} } @article { ISI:000270126100012, title = {Organocatalytic enantioselective synthesis of beta-blockers: (S)-propranolol and (S)-naftopidil}, journal = {Tetrahedron-Asymmetry}, volume = {20}, number = {15}, year = {2009}, month = {AUG}, pages = {1767-1770}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient enantioselective synthesis of beta-adrenergic blockers (S)-propranolol and (S)-naftopidil with \> 98\% ee using an L-proline-catalyzed alpha-aminoxylation of an aldehyde as a key step is described. (c) 2009 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2009.07.002}, author = {Panchgalle, Sharad P. and Gore, Rohitkumar G. and Chavan, Subhash P. and Kalkote, Uttam R.} } @article { ISI:000278985800034, title = {Enantioselective synthesis of (R)-(+)-alpha-lipoic acid via proline-catalyzed sequential alpha-aminoxylation and HWE olefination of aldehyde}, journal = {Tetrahedron Letters}, volume = {51}, number = {27}, year = {2010}, month = {JUL}, pages = {3587-3589}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient enantioselective synthesis of (R)-(+)-alpha-lipoic acid is described, in high optical purity (\>97\% ee), using L-proline-catalyzed sequential alpha-aminoxylation and Horner-Wadsworth-Emmons olefination of aldehyde as the key step. (C) 2010 Elsevier Ltd. All rights reserved.

}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2010.05.007}, author = {Panchgalle, Sharad P. and Jogdand, Ganesh F. and Chavan, Subhash P. and Kalkote, Uttam R.} } @article { ISI:000272936000061, title = {Fluconazole analogues containing 2H-1,4-benzothiazin-3(4H)-one or 2H-1,4-benzoxazin-3(4H)-one moieties, a novel class of anti-Candida agents}, journal = {Bioorganic \& Medicinal Chemistry Letters}, volume = {20}, number = {2}, year = {2010}, month = {JAN}, pages = {722-725}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

As a part of our program to develop new antifungal agents, a series of fluconazole analogues was designed and synthesized wherein one of the triazole moieties in fluconazole was replaced with 2H-1,4-benzothiazin-3(4H)-one or 2H-1,4-benzoxazin-3(4H)-one moiety. The new chemical entities thus synthesized were screened against various fungi and it was observed that the compounds 4a and 4i are potent inhibitors of Candida strains. The structure-activity relationship for these compounds is discussed. (C) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {antifungal, Benzothiazinone, Benzoxazinone, Fluconazole}, issn = {0960-894X}, doi = {10.1016/j.bmcl.2009.11.071}, author = {Borate, Hanumant B. and Maujan, Suleman R. and Sawargave, Sangmeshwer P. and Chandavarkar, Mohan A. and Vaiude, Sharangi R. and Joshi, Vinay A. and Wakharkar, Radhika D. and Iyer, Ramki and Kelkar, Ramesh G. and Chavan, Subhash P. and Kunte, Sunita S.} } @article { ISI:000278451000017, title = {Formal synthesis of (+/-)-camptothecin via tricyclic lactone as key synthon}, journal = {Tetrahedron Letters}, volume = {51}, number = {23}, year = {2010}, month = {JUN}, pages = {3099-3101}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Formal synthesis of (+/-)-camptothecin via CDE tricyclic lactone employing tandem Michael addition, Dieckmann condensation and addition-elimination reaction as key steps starting from glycinate is described. (C) 2010 Elsevier Ltd. All rights reserved.

}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2010.04.019}, author = {Chavan, Subhash P. and Dhawane, Abasaheb N. and Kalkote, Uttam R.} } @article { ISI:000284728400014, title = {Organocatalytic asymmetric synthesis of (-)-delta-coniceine based on sequential proline-catalyzed asymmetric alpha-amination-HWE olefination}, journal = {Tetrahedron-Asymmetry}, volume = {21}, number = {19}, year = {2010}, month = {OCT}, pages = {2399-2401}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An efficient asymmetric synthesis of (-)-delta-coniceine via sequential proline-catalyzed asymmetric alpha-amination and Horner-Wadsworth-Emmons olefination of an aldehyde with excellent enantiomeric excess (\>99\%) and high yields (overall yield 44\%) is described. (C) 2010 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2010.08.009}, author = {Panchgalle, Sharad P. and Bidwai, Harshad B. and Chavan, Subhash P. and Kalkote, Uttam R.} } @article { ISI:000286862200012, title = {Asymmetric total synthesis of (2S,3S)-3-hydroxypipecolic acid}, journal = {Tetrahedron Letters}, volume = {52}, number = {3}, year = {2011}, month = {JAN}, pages = {404-406}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A synthetic route to (2S,3S)-3-hydroxypipecolic acid was achieved from readily available nonchiral pool starting material cis-2-butene-1,4-diol and involved Claisen orthoester rearrangement, Sharpless asymmetric dihydroxylation and intramolecular lactamisation of azido lactone as the key steps. (C) 2010 Elsevier Ltd. All rights reserved.

}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2010.11.062}, author = {Chavan, Subhash P. and Dumare, Nilesh B. and Harale, Kishor R. and Kalkote, Uttam R.} } @article { ISI:000291139700014, title = {Convenient formal synthesis of (2S,3S)-3-hydroxy pipecolic acid}, journal = {Tetrahedron-Asymmetry}, volume = {22}, number = {5}, year = {2011}, month = {MAR}, pages = {587-590}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A convenient synthesis of (2S,3S)-3-hydroxy pipecolic acid starting from inexpensive and easily available L-(+)-tartaric acid has been described. (C) 2011 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2011.02.023}, author = {Chavan, Subhash P. and Harale, Kishor R. and Dumare, Nilesh B. and Kalkote, Uttam R.} } @article { ISI:000290409100007, title = {Exploration of L-proline-catalyzed -aminoxylation of aldehyde to (S)-guaifenesin-related drug molecules}, journal = {Synthetic Communications}, volume = {41}, number = {13}, year = {2011}, month = {MAY}, pages = {PII 937137930}, publisher = {TAYLOR \& FRANCIS INC}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

[image omitted] An efficient enantioselective synthesis of (S)-guaifenesin with 99\% ee using L-proline-catalyzed -aminoxylation of aldehyde as key step is described and explored for asymmetric syntheses of (S)-moprolol and (R)-methocarbamol.

}, keywords = {-Aminoxylation, guaifenesin, methocarbamol, moprolol, Proline}, issn = {0039-7911}, doi = {10.1080/00397911.2010.493631}, author = {Panchgalle, Sharad P. and Kunte, Sunita S. and Chavan, Subhash P. and Kalkote, Uttam R.} } @article { ISI:000293168000044, title = {Novel hybrids of fluconazole and furanones: design, synthesis and antifungal activity}, journal = {Bioorganic \& Medicinal Chemistry Letters}, volume = {21}, number = {16}, year = {2011}, month = {AUG}, pages = {4873-4878}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

During our efforts to develop new antifungal agents, a number of hybrid molecules containing furanones and fluconazole pharmacophores were designed and synthesized. The new chemical entities thus synthesized were tested for their potential as antifungal agents against various fungal strains and it was observed that the compounds with general structure 7 were potent inhibitors of Candida albicans ATCC 24433, Candida glabrata ATCC 90030, Candida tropicalis ATCC 750 and Candida neoformans ATCC 34664 while the fluconazole analogues 12 exhibited antifungal activity against Candida albicans ATCC 24433 and Candida glabrata ATCC 90030. The structure-activity relationship for these compounds is discussed. The synthetic strategies used in the present work have potential to prepare a large number of compounds for further refinement of structures to obtain molecules suitable for development as antifungal drugs. (C) 2011 Elsevier Ltd. All rights reserved.

}, keywords = {Antifungal activity, Fluconazole, Furanones}, issn = {0960-894X}, doi = {10.1016/j.bmcl.2011.06.022}, author = {Borate, Hanumant B. and Sawargave, Sangmeshwer P. and Chavan, Subhash P. and Chandavarkar, Mohan A. and Iyer, Ramki and Tawte, Amit and Rao, Deepali and Deore, Jaydeep V. and Kudale, Ananada S. and Mahajan, Pankaj S. and Kangire, Gopinath S.} } @article { ISI:000295552400021, title = {One-step synthesis of 4-alkyl-3-aryl-2,6-dicyanoanilines and their use in the synthesis of highly functionalized 2,3,5,6,7-and 2,3,4,5,7-substituted indoles}, journal = {Tetrahedron Letters}, volume = {52}, number = {42}, year = {2011}, month = {OCT}, pages = {5491-5493}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A three-component, one-step method for the synthesis of 4-alkyl-3-aryl-2,6-dicyanoanilines involving reaction of alkyl aldehyde, malononitrile and aryl aldehyde in presence of morpholine is reported. Highly functionalized 2,3,5,6,7- and 2,3,4,5,7-substituted indoles were prepared from these dicyanoanilines by reaction with ethyl bromoacetate. These substituted dicyanoanilines and indoles have a potential to be converted into various other compounds taking advantage of various functional groups present in these molecules. (C) 2011 Elsevier Ltd. All rights reserved.

}, keywords = {aldehydes, Dicyanoanilines, indoles, Malononitrile}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2011.08.064}, author = {Sawargave, Sangmeshwer P. and Kudale, Ananada S. and Deore, Jaydeep V. and Bhosale, Dattatry S. and Divse, Jaisingh M. and Chavan, Subhash P. and Borate, Hanumant B.} } @article { ISI:000310863400014, title = {Enantioselective synthesis of the essential oil and pheromonal component ar-himachalene by a chiral pool and chirality induction approach}, journal = {Tetrahedron-Asymmetry}, volume = {23}, number = {18-19}, year = {2012}, month = {OCT}, pages = {1410-1415}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The enantioselective synthesis of both isomers of ar-himachalene has been achieved starting from enantiomerically pure citronellal and p-methyl alpha-methyl styrene as an application of a chiral pool and chirality induction approach, respectively. The key reactions involved in the synthesis include the Sharpless asymmetric dihydroxylation for the induction of chirality at benzylic carbon bearing the methyl group and the use of a hypervalent iodine reagent or trimethylsilyldiazomethane (TMSCHN2) for the six to seven membered ring expansion. (C) 2012 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2012.09.008}, author = {Chavan, Subhash P. and Khatod, Harshali S.} } @article { ISI:000303429600017, title = {Formal synthesis of (-)-stemoamide using a useful epimerization at C-8}, journal = {Tetrahedron Letters}, volume = {53}, number = {21}, year = {2012}, month = {MAY}, pages = {2647-2650}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The formal synthesis of (-)-stemoamide was achieved starting from L-pyroglutamic acid. The key steps used are the allylation using BF3 center dot OEt2, ring closing metathesis, allylic oxidation and a novel epimerization at C8. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Allylation, Allylic oxidation, Pyroglutamic acid, Ring closing metathesis, Stemoamide}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2012.03.054}, author = {Chavan, Subhash P. and Harale, Kishor R. and Puranik, Vedavati G. and Gawade, Rupesh L.} } @article { ISI:000308778100017, title = {Highly diastereoselective total synthesis of (+/-)-heritonin and (+/-)-heritol}, journal = {Tetrahedron}, volume = {68}, number = {40}, year = {2012}, month = {OCT}, pages = {8509-8514}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A highly diastereoselective synthesis of heritol and heritonin by intramolecular cyclization on a preformed sensitive butenolide functionality is described. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Butenolide, cyclization, Dihydroxylation, Friedel-Crafts acylation, Tetralone}, issn = {0040-4020}, doi = {10.1016/j.tet.2012.07.020}, author = {Chavan, Subhash P. and Garai, Sumanta and Kalkote, Uttam R.} } @article { ISI:000307601300015, title = {Very practical and selective method for PMB protection of alcohols}, journal = {Tetrahedron Letters}, volume = {53}, number = {35}, year = {2012}, month = {AUG}, pages = {4683-4686}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A very simple, practical and efficient one-step heterogeneous protocol for the PMB protection of alcohols using Amberlyst-15 has been developed. The stability and hazard issues regarding PMBCI and PMBBr are totally avoided by directly using anisyl alcohol for the protection. Alcohols are protected in very good yields. The selective mono-PMB protection of diols as well as di-PMB protection of diols was achieved in good yields, along with the demonstration of recyclability of the catalyst. (c) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {4-Methoxybenzyl alcohol, 4-Methoxybenzyl protection, Amberlyst-15, Di-PMB protection, Mono-PMB protection}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2012.06.084}, author = {Chavan, Subhash P. and Harale, Kishor R.} } @article { ISI:000323020400047, title = {One-pot migration-formylation of benzyl aryl ethers under duff reaction condition}, journal = {Tetrahedron Letters}, volume = {54}, number = {35}, year = {2013}, month = {AUG}, pages = {4789-4792}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A one-pot migration-formylation of benzyl aryl ethers under Duff reaction condition is described. The reaction was performed with HMTA (hexamethylene tetramine) and TFA (trifluoroacetic acid). Under the optimal reaction conditions, a variety of Bn and PMB ethers underwent ortho rearrangement. (C) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Benzyl aryl ethers, Duff reaction, Hexamethylene tetramine, One-pot, ortho Rearrangement}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2013.06.133}, author = {Chavan, Subhash P. and Lasonkar, Pradeep B.} } @article { ISI:000315540200007, title = {One-step method for the synthesis of aryl olefins from aryl aldehydes and aliphatic aldehydes}, journal = {Tetrahedron Letters}, volume = {54}, number = {12}, year = {2013}, month = {MAR}, pages = {1528-1530}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A conceptually new one-step reaction affording unexpected aryl olefinic product from aromatic aldehyde, aliphatic aldehyde and malononitrile in the presence of acetic acid-ammonium acetate under mild reaction conditions without using any metal catalyst is reported. This novel reaction was used to prepare a number of substituted aryl olefins including new molecules. (c) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Aliphatic aldehyde, Aromatic aldehyde, Aryl olefin, Dicyanoaniline, Malononitrile}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2013.01.008}, author = {Borate, Hanumant B. and Gaikwad, Supriya H. and Kudale, Ananada S. and Chavan, Subhash P. and Pharande, Shrikant G. and Wagh, Vitthal D. and Sawant, Vikram S.} } @article { ISI:000323093300010, title = {Short synthesis of (2S,3S)-3-hydroxypipecolic acid}, journal = {Tetrahedron Letters}, volume = {54}, number = {36}, year = {2013}, month = {SEP}, pages = {4851-4853}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A convenient synthesis of (2S,3S)-3-hydroxypipecolic acid starting from cheap and abundant L-(+)-tartaric acid has been achieved. The strategy employs selective ester reduction and reductive lactamization as key steps. (C) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Reductive lactamization, Selective deprotection, Wittig reaction}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2013.06.111}, author = {Chavan, Subhash P. and Harale, Kishor R. and Pawar, Kailash P.} } @article { ISI:000328335000013, title = {Simple synthesis of the novel antihistaminic drug olopatadine hydrochloride}, journal = {Synthesis-Stuttgart}, volume = {45}, number = {24}, year = {2013}, month = {DEC}, pages = {3399-3403}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A new alternative route for the synthesis of olopatadine is described. The present strategy involves a Lewis acid mediated ring opening of a cyclic ether to introduce 3-(dimethylamino)propylidene group as the side chain.

}, keywords = {antihistaminic drugs, chelates, Lewis acids, spiro compounds, zinc}, issn = {0039-7881}, doi = {10.1055/s-0033-1340008}, author = {Chavan, Subhash P. and Lasonkar, Pradeep B.} } @article { ISI:000344825300009, title = {Chiron approach to formal synthesis of both antipodes of cis 3-hydroxypipecolic acid}, journal = {Tetrahedron Letters}, volume = {55}, number = {47}, year = {2014}, month = {NOV}, pages = {6423-6426}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The efficient and practical formal syntheses of both enantiomers of cis 3-hydroxypipecolic acid were accomplished from cis aziridine-2-carboxylate as the common synthetic precursor. The key steps involved are stereo and regioselective aziridine ring opening, reductive cyclization and selective N-debenzylation over O-debenzylation reactions. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {3-Hydroxypipecolic acid, Aziridine ring opening, Aziridine-2-carboxylate, Piperidine alkaloids, Selective debenzylation}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2014.09.118}, author = {Chavan, Subhash P. and Khairnar, Lalit B. and Chavan, Prakash N. and Dumare, Nilesh B. and Kalbhor, Dinesh B. and Gonnade, Rajesh G.} } @article { ISI:000343624300007, title = {Efficient and mild method for preparation of allylic amines from aziridine-2-alcohols using PPh3/I-2/imidazole}, journal = {Tetrahedron Letters}, volume = {55}, number = {43}, year = {2014}, month = {OCT}, pages = {5905-5907}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Allylic amines are synthesized in good to excellent yields by treatment of aziridine-2-alcohols with PPh3/I-2/imidazole in THF as solvent under mild conditions. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {Chiral allylic amine, Chiral aziridine-2-alcohols, PPh3/iodine/imidazole, Reductive elimination}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2014.08.078}, author = {Chavan, Subhash P. and Khairnar, Lalit B. and Chavan, Prakash N.} } @article { ISI:000345902500007, title = {Facile and convenient synthesis of (+/-)-Biotin via MgCl2/Et3N-mediated C-C coupling and mitsunobu reaction}, journal = {Synlett}, volume = {25}, number = {20}, year = {2014}, month = {DEC}, pages = {2879-2882}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A synthesis of (+/-)-biotin is described starting from simple starting materials viz. cyclohexanone and amino malonic acid ester. The key steps involved are MgCl2/Et3N coupling of amino malonic acid ester derivative and acid chloride, Mitsunobu reaction, ozonolysis, Staudinger reduction, novel urea formation, and subsequent dibenzylation. This approach is economical and involves high-yielding steps and simple reaction conditions.

}, keywords = {Appel reaction, biotin, Mitsunobu reaction, Ozonolysis, Staudinger reduction}, issn = {0936-5214}, doi = {10.1055/s-0034-1379365}, author = {Chavan, Subhash P. and Chavan, Prakash N. and Lasonkar, Pradeep B. and Khairnar, Lalit B. and Kadam, Appasaheb L.} } @article { ISI:000341083400001, title = {Novel, concise and efficient protocol for non-natural piperidine compounds}, journal = {RSC Advances}, volume = {4}, number = {62}, year = {2014}, month = {JUL}, pages = {32594-32598}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Formal synthesis of L-altro-1-deoxynojirimycin, cis-3-hydroxypipecolic acid along with synthesis of (R)-piperidinol and a conceptually different advanced intermediate for non-natural piperidine alkaloids is reported from cis-butene-1,4-diol. The key reactions involved are Johnson-Claisen rearrangement, Sharpless asymmetric dihydroxylation, reductive lactamization and novel regioselective elimination.

}, issn = {2046-2069}, doi = {10.1039/c4ra04558k}, author = {Chavan, Subhash P. and Dumare, Nilesh B. and Pawar, Kailash P.} } @article {46405, title = {Protecting group free and scalable approach towards total synthesis of (-)-venlafaxine}, journal = {RSC Advances}, volume = {4}, year = {2014}, month = {FEB}, pages = {14468-14470}, type = {Article}, abstract = {

A protecting group free asymmetric total synthesis of (-)-venlafaxine is reported. The strategy employs Sharpless epoxidation and regio-selective epoxide ring opening by an in situ generated Gilman reagent as key steps. This paper reports a 53\% overall yield in 6 steps for total synthesis of (-)-venlafaxine.

}, issn = {2046-2069}, doi = {10.1039/c4ra00840e}, author = {Chavan, Subhash P. and Pawar, Kailash P. and Garai, Sumanta} } @article { ISI:000342873800010, title = {Short enantioselective total synthesis of (R)- and (S)-pipecolic acid}, journal = {Tetrahedron-Asymmetry}, volume = {25}, number = {16-17}, year = {2014}, month = {SEP}, pages = {1246-1251}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A convenient and practical total synthesis of (R)- and (S)-pipecolic acid has been achieved by utilizing chiral cis-aziridine-2-carboxylate as the common synthetic precursor. The synthesis involves regioselective reductive cleavage of the aziridine ring and Wittig olefination as key reactions. (C) 2014 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2014.08.001}, author = {Chavan, Subhash P. and Khairnar, Lalit B. and Chavan, Prakash N. and Kalbhor, Dinesh B.} } @article { ISI:000345660300032, title = {Stereospecific synthetic approach towards tamiflu using the ramberg-backlund reaction from cysteine hydrochloride}, journal = {RSC Advances}, volume = {4}, number = {107}, year = {2014}, month = {NOV}, pages = {62281-62284}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

The stereospecific formal synthesis of Tamiflu from L-cysteine hydrochloride as the chiral source is described. The notable feature of the present strategy is the Ramberg-Backlund reaction and Sharpless-Reich protocol as the key chemical transformations to access the cyclohexene skeleton of Tamiflu.

}, issn = {2046-2069}, doi = {10.1039/c4ra10391b}, author = {Chavan, Subhash P. and Chavan, Prakash N. and Gonnade, Rajesh G.} } @article { ISI:000341938100024, title = {Total syntheses of D-allo-1-deoxynojirimycin and L-talo-1-deoxynojirimycin via reductive cyclization}, journal = {RSC Advances}, volume = {4}, number = {77}, year = {2014}, month = {AUG}, pages = {40852-40858}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Synthesis of a polyhydroxypiperidine framework for L-talo-1-deoxynojirimycin and D-allo-1-deoxynojirimycin was achieved from L-tartaric acid by employing flash dihydroxylation and reductive lactamisation as the key steps.

}, issn = {2046-2069}, doi = {10.1039/c4ra06884j}, author = {Chavan, Subhash P. and Dumare, Nilesh B. and Pawar, Kailash P.} } @article { ISI:000341552000004, title = {Unusual, selective, reductive, deoxygenation of cyclopentenone alcohols}, journal = {Tetrahedron Letters}, volume = {55}, number = {38}, year = {2014}, month = {SEP}, pages = {5241-5243}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A selective, reductive, deoxygenation of 2-aryl-4-hydroxycyclopent-2-en-1-ones to afford 2-aryl-cyclopent-2-en-1-ones was achieved by NaBH4-CeCl3 in methanol. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {Cyclopentenone alcohol, Enone, Luche reduction, Reductive deoxygenation}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2014.07.122}, author = {Bavikar, Suhas R. and Lasonkar, Trupti P. and Chavan, Subhash P. and Borate, Hanumant B.} } @article {45947, title = {Chirality induction and chiron approaches to enantioselective total synthesis of alpha-lipoic acid}, journal = {Tetrahedron}, volume = {71}, year = {2015}, month = {JUN }, pages = {4213-4218}, type = {Article}, abstract = {

An efficient, short and convenient asymmetric synthesis of (R)-(+)-lipoic acid in seven steps from chiral hydroxy aldehyde with 32.5\% overall yield is described. Synthesis of S and R enantiomers of a-lipoic acid from cis-1,4-butene diol derived chiral lactone is reported with 34 \% overall yield. The present synthesis involves use of simple reaction conditions making it a convenient synthesis. (C) 2015 Elsevier Ltd. All rights reserved.

}, keywords = {Chiral pool, Chirality induction, enantioselective, Lipoic acid, sharpless asymmetric dihydroxylation}, issn = {0040-4020}, doi = {10.1016/j.tet.2015.04.090}, author = {Chavan, Subhash P. and Pawar, Kailash P. and Praveen, Ch and Patil, Niteen B.} } @article { ISI:000355987900093, title = {Enantioselective syntheses of (R)-pipecolic acid, (2R,3R)-3-hydroxypipecolic acid, beta-(+)-conhydrine and (-)-swainsonine using an aziridine derived common chiral synthon}, journal = {RSC Advances}, volume = {5}, number = {62}, year = {2015}, month = {MAY}, pages = {50580-50590}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Concise total syntheses of (R)-pipecolic acid, (R)-ethyl-6-oxopipecolate, (2R, 3R)-3-hydroxypipecolic acid and formal syntheses of beta-(+)-conhydrine, (-)-lentiginosine, (-)-swainsonine and 1,2-di-epi-swainsonine have been accomplished starting from a common chiral synthon. The present strategy employs regioselective aziridine ring opening, Wittig olefination and RCM as the key chemical transformations.

}, issn = {2046-2069}, doi = {10.1039/c5ra06429e}, author = {Chavan, Subhash P. and Khairnar, Lalit B. and Pawar, Kailash P. and Chavan, Prakash N. and Kawale, Sanket A.} } @article { ISI:000349061500011, title = {Formal syntheses of (2R,3R)-3-hydroxy pipecolic acid and (2R,3S)-3-hydroxy pipecolic acid from L-ascorbic acid}, journal = {Tetrahedron Letters}, volume = {56}, number = {6}, year = {2015}, month = {FEB}, pages = {805-807}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Formal syntheses of both cis and trans 3-hydroxy pipecolic acids is achieved from L-ascorbic acid. Present synthesis describes use of chiral pool approach in which epimerization, Staudinger reaction and Cyclization reactions were employed as key steps. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {3-Hydroxy pipecolic acid, cyclization, Epimerization, L-Ascorbic acid}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2014.12.103}, author = {Chavan, Subhash P. and Dumare, Nilesh B. and Pawar, Kailash P.} } @article { ISI:000351584500007, title = {Synthesis of 3-ethyl-4-metyl-1h,5-dihydro-2h-pyrrol-2-one by novel palladium(ii)-catalyzed cyclization and ring-closing metathesis}, journal = {Synthesis-Stuttgart}, volume = {47}, number = {7}, year = {2015}, month = {APR}, pages = {955-960}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Synthesis of 3-ethyl-4-methyl-1,5-dihydro-2H-pyrrol-2-one is described starting from commercially available allylamine and 4-methoxybenzylamine employing palladium-catalyzed cyclization or ring-closing metathesis as the key steps.

}, keywords = {antidiabetic, cyclization, glimepiride, lactams, metabolite, pyrrolinone, Ring-closing metathesis}, issn = {0039-7881}, doi = {10.1055/s-0034-1379985}, author = {Chavan, Subhash P. and Pathak, Ashok B. and Pawar, Kailash P.} } @article { ISI:000352671600006, title = {Total synthesis of (R)-lipoic acid and (S)-lipoic acid via an Mn (III)-salen-catalyzed oxidative kinetic resolution}, journal = {Tetrahedron-Asymmetry}, volume = {26}, number = {5-6}, year = {2015}, month = {MAR}, pages = {281-287}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The asymmetric synthesis of both the antipodes of alpha-lipoic acid is described. The total synthesis of racemic and asymmetric lipoic acid is achieved from propane 1,3-diol. This work reports the use of Mn (III)-salen-catalyzed oxidative kinetic resolution as the key step to obtain enantiomerically pure (R)- and (S)-lipoic acid. The undesired product formed during the resolution can be recycled to achieve the desired isomer. (C) 2015 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2015.02.001}, author = {Purude, Abhijeet N. and Pawar, Kailash P. and Patil, Niteen B. and Kalkote, Uttam R. and Chavan, Subhash P.} } @article { ISI:000377612300010, title = {Asymmetric total synthesis of L-allo-1-deoxynojirimycin}, journal = {Arkivoc}, number = {2}, year = {2016}, month = {OCT}, pages = {137-147}, publisher = {ARKAT USA INC}, address = {C/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USA}, abstract = {

Asymmetric total synthesis of L-allo-1-deoxynojirimycin (L-allo-DNJ) was achieved from cis-butene-1,4-diol by employing Sharpless asymmetric dihydroxylation, stereoselective flash dihydroxylation and ring enlargement reactions as key steps.

}, keywords = {diastereoselective flash dihydroxylation, ring-enlargement reaction, sharpless asymmetric dihydroxylation}, issn = {1551-7004}, doi = {10.3998/ark.5550190.p009.295}, author = {Chavan, Subhash P. and Dumare, Nilesh B. and Pawar, Kailash P. and Chavan, Prakash N. and Khairnar, Lalit B.} } @article { ISI:000377515200041, title = {Exploration of the diastereoselectivity in an unusual Grignard reaction and its application towards the synthesis of styryl lactones 7-epi-(+)-goniodiol and 8-epi-(-)-goniodiol}, journal = {RSC Advances}, volume = {6}, number = {56}, year = {2016}, month = {MAY}, pages = {50721-50725}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An unusual diastereoselective Grignard reaction is explored, where the Grignard reagents are derived from 1,n-dihaloalkanes. A steric bias due to the presence of a quaternary centre adjacent to the acetonide ester at the benzylic position is responsible for the formation of an intramolecularly reduced product in almost quantitative yield. This steric hindrance is responsible for the diastereoselectivity observed with a variety of aromatic as well as aliphatic esters. The unusual Grignard reaction furnishes long chain secondary alcohols possessing a terminal olefin, which are synthetically important intermediates. As an application of this method, the diastereoselective synthesis of styryl lactones viz. 7-epi-(+)-goniodiol (29) and 8-epi(-)-goniodiol (30) has been achieved.

}, issn = {2046-2069}, doi = {10.1039/c6ra03192g}, author = {Chavan, Subhash P. and Khatod, Harshali S. and Das, Tamal and Vanka, Kumar} } @article {43546, title = {Application of unusual grignard reaction for the stereoselective synthesis of antidepressant drug (R)-(-)-venlafaxine}, journal = {Synthesis-Stuttgart}, volume = {49}, year = {2017}, month = {MAR}, pages = {1410-1418}, abstract = {An enantioselective synthesis of antidepressant drug (R)-(-)-venlafaxine is accomplished as an application of recently explored unusual Grignard reaction. An innovative method for the generation of chirality at extremely reactive benzylic center along with determination of absolute stereochemistry has been discussed. The key steps involved in the synthesis include Sharpless asymmetric dihydroxylation for the induction of chirality and an unusual Grignard reaction.}, doi = {10.1055/s-0036-1588911}, author = {Chavan, Subhash P. and Khatod, Harshali S.} } @article {43264, title = {Hybrids of thienopyrimidinones and thiouracils as anti-tubercular agents: SAR and docking studies}, journal = {European Journal of Medicinal Chemistry}, volume = {127}, year = {2017}, month = {JAN}, abstract = {

A number of hybrid molecules containing thienopyrimidinones and thiouracil moieties were designed, synthesized and tested against Mycobacterium tuberculosis H37Ra wherein it was observed that the compounds 11-1514 exhibited antitubercular activity in vitro (MIC 7.6{\textendash}19.1 μg/ml, 12{\textendash}35 μM) against dormant stage while compound 15 exhibited antitubercular activity in vitro against dormant (MIC 23.4 μg/ml, 41 μM) as well as active (MIC 25.4 μg/ml, 45 μM) stage. Structural modifications of compound 15 were carried out to study the structure-activity relationship and it was observed that compound 18 exhibited antitubercular activity comparable to compound 15. Cytotoxicity studies revealed that these molecules were non-toxic. The docking study of compound 15 showed that there was binding with the active site of mycobacterial pantothenate synthetase. Further docking studies led to the synthesis of the compounds 16 and 17 and the antitubercular activity screening results showed that these compounds have significant antitubercular activity. The compounds 15-18 (MIC 11{\textendash}29 μg/ml, 19{\textendash}51 μM) can be used as starting points for further optimization. The synthetic strategies used in the present work have potential to prepare a large number of compounds for further refinement of structures and the present results will be very useful in the development of a new class of antimycobacterial agents.

}, doi = {10.1016/j.ejmech.2017.01.009}, author = {Pisal, Mahesh M. and Nawale, Laxman U. and Patil, Manoj and Bhansali, Sujit G. and Gajbhiye, Jayant M. and Sarkar, Dhiman and Chavan, Subhash P. and Borate, Hanumant B.} } @article {43261, title = {Synthesis and cell imaging applications of fluorescent mono/di/tri-heterocycl- yl-2,6-dicyanoanilines}, journal = {Bioorganic \& Medicinal Chemistry Letters}, volume = {27}, year = {2017}, month = {DEC}, pages = {979-988}, abstract = {

Synthesis of 3,4,5-triheterocyclyl-2,6-dicyanoanilines, starting from heterocyclic aldehydes and 1,2-diheterocycle-substituted ethanones, is described. 2,6-Dicyanoanilines with one or two heterocyclic substituents have also been synthesized. It was found that some of these molecules have selective cell-staining properties useful for cell imaging applications. The compounds 1g, 10f and 11 were found to stain cytoplasm of the cells in contact but not the nucleus while the compound 12 showed affinity to apoptotic cells resulting in blue fluorescence. The cell imaging results with compound 12 were similar to Annexin V-FITC, a known reagent containing recombinant Annexin V conjugated to green-fluorescent FITC dye, used for detection of apoptotic cells. These compounds were found to be non-cytotoxic and have potential application as cell imaging agents.

}, doi = {10.1016/j.bmcl.2016.12.074}, author = {Pisal, Mahesh M. and Annadate, Ritesh A. and Athalye, Meghana C. and Kumar, Dipak and Chavan, Subhash P. and Sarkar, Dhiman and Borate, Hanumant B.} } @article {45487, title = {Synthesis of 3-azidopiperidine skeleton employing ceric ammonium nitrate (CAN)-mediated regioselective azidoalkoxylation of enol ether: total synthesis of d-2 receptor agonist (+/-)-quinagolide}, journal = {Organic letters }, volume = {20}, year = {2018}, month = {NOV }, pages = {7011-7014}, type = {Article }, abstract = {The total synthesis of (+/-)-quinagolide, which is a D-2 receptor agonist, was accomplished via a ceric ammonium nitrate (CAN)-mediated regioselective azidoalkoxylation of enol ether route. Key features of the synthesis include Claisen rearrangement, PPTS (pyridinium p-toluene-sulfonate)-catalyzed one-pot acetal deprotection, followed by a diastereoselective Henry reaction, which enables construction of the required trans ring junction and CAN-mediated regioselective azidoalkoxylation of enol ether. The PPTS-catalyzed intramolecular diastereoselective Henry reaction to fix three contiguous stereocenters on tetrahydronaphthalene and the first-of-its-kind synthesis of the 3-azidopiperidine skeleton, using a CAN -mediated regioselective azidoalkoxylation of enol ether, are important findings of the present work.}, issn = {1523-7060}, doi = { 10.1021/acs.orglett.8b02900}, author = {Chavan, Subhash P. and Kadam, Appasaheb L. and Lasonkar, Pradeep B. and Gonnade, Rajesh G.} } @article {46435, title = {Enantioselective formal total synthesis of (-)-quinagolide}, journal = {Organic Letters}, volume = {21}, year = {2019}, month = {NOV}, pages = {9089-9093}, type = {Article}, abstract = {

The enantioselective formal total synthesis of (-)-quinagolide has been accomplished in a linear sequence of 8 purification steps from pyridine. The key steps are (a) organocatalyzed Diets-Alder reaction for fixing all three stereocenters on piperidine ring; (b) protecting group enabled deoxygenation of isoquinuclidine skeleton under Birch reduction condition; (c) Lewis acid (TiCl4) catalyzed intramolecular Friedel-Crafts cyclization of dicarboxylic acid; and (d) one-pot diastereoselective ketone reduction-intramolecular cyclization to form oxazolidinone which enables trans-geometry installation. During the course of the synthesis, an interesting reductive cleavage of the C-N bond in the electron-deficient isoquinuclidine skeleton under the Birch reduction conditions has been observed. This is the first synthetic effort to access the core skeleton of (-)-quinagolide.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.9b03477}, author = {Chavan, Subhash P. and Kadam, Appasaheb L. and Gonnade, Rajesh G.} } @article {46436, title = {Formal synthesis of brivaracetam: a key to construct the pyrrolidone scaffold using Pd-catalyzed oxidative cyclization and ring-closing metathesis reaction}, journal = {Tetrahedron Letters}, volume = {60}, year = {2019}, month = {NOV}, pages = {151249}, type = {Article}, abstract = {

A short and efficient synthetic approach for brivaracetam has been accomplished via two different routes which utilize Pd-catalyzed oxidative cyclization and ring-closing metathesis (RCM) as the key reaction. These two routes are novel, simple, scalable and rely on (E)-pent-2-en-1-ol and valeraldehyde as a commercially available starting material to yield brivaracetam with good overall yield. (C) 2019 Published by Elsevier Ltd.

}, keywords = {Antiepileptic drugs, Pd-catalyzed oxidative cyclization, pyrrolinone, Ring-closing metathesis reaction}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2019.151249}, author = {Chavan, Subhash P. and Kawale, Sanket A. and Chavan, Prakash N.} } @article {46115, title = {Total synthesis of (+/-)-quinagolide: a potent D-2 receptor agonist for the treatment of hyperprolactinemia}, journal = {ACS Omega}, volume = {4}, year = {2019}, month = {MAY}, pages = {8231-8238}, type = {Article}, abstract = {

A potent dopamine (D-2) receptor agonist (+/-)-quinagolide, which is used for the treatment of hyperprolactinemia, was synthesized using the ring closing metathesis (RCM) approach from meta-hydroxybenzaldehyde as the starting material. The key features of this synthesis are pyrolytic elimination, late-stage expedient synthesis of functionalized trans-fused tetrahydropyridine-3-carboxylates from olefin 6, via conjugate addition-elimination upon acetate 11, followed by RCM and phenyliodine bis(trifluoroacetate) (PIFA)-mediated Hofmann rearrangement of piperidine-3-carboxamide, which enables the synthesis of 3-aminopiperidine skeleton of quinagolide. For the total synthesis of natural products such as ergot alkaloids, late-stage synthesis of functionalized trans-fused tetrahydropyridine-3-carboxylates using RCM and PIFA-mediated Hofmann rearrangement of piperidine-3-carboxamide, which allows quick access to the synthetically challenging 3-aminopiperidine skeleton, are the main achievements of the present work.

}, issn = {2470-1343}, doi = {10.1021/acsomega.9b00903}, author = {Chavan, Subhash P. and Kadam, Appasaheb L. and Kawale, Sanket A.} } @article {46597, title = {Chiron approach to formal synthesis of both antipodes of cis 3-hydroxypipecolic acid (vol 55, pg 6423, 2014)}, journal = {Tetrahedron Letters}, volume = {61}, year = {2020}, month = {DEC }, pages = {152644}, type = {Correction}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2020.152644}, author = {Chavan, Subhash P. and Khairnar, Lalit B. and Chavan, Prakash N. and Dumare, Nilesh B. and Kalbhor, Dinesh B. and Gonnade, Rajesh G.} } @article {46913, title = {Enolate-mediated regioselective synthesis of 1,2,3-triazoles via azide-aldehydes or ketones [3+2]-cycloaddition reactions in aqueous phase}, journal = {Tetrahedron Letters}, volume = {61}, year = {2020}, month = {MAR}, pages = {151662}, type = {Article}, abstract = {

A synthetic route for the direct conversion of arylazides into the corresponding trizoles via phase transfer catalyst-assisted [3+2] cycloaddition reaction under basic conditions in aqueous medium is reported. This synthetic methodology, which offers high yields and excellent regioselectivity for varieties of triazoles at 100 degrees C for 24 h-48 h and this {\textquoteleft}greener{\textquoteright} synthesis constitutes an alternative to the previously reported well established click reactions. Published by Elsevier Ltd.

}, keywords = {Azides plus aldehydes or ketones, Click chemistry, triazoles, Water}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2020.151662}, author = {Tripathi, Anupam and Rode, V, Chandrashekhar and Llop, Jordi and Chavan, Subhash P. and Joshi, Sameer M.} } @article {46992, title = {Furan-derived chiral bicycloaziridino lactone synthon: collective syntheses of oseltamivir phosphate (Tamiflu), (S)-pipecolic acid and its 3-hydroxy derivatives}, journal = {Chemistry-An Asian Journal}, volume = {15}, year = {2020}, month = {FEB }, pages = {415-424}, type = {Article}, abstract = {

A unified synthetic strategy for oseltamivir phosphate (tamiflu), (S)-pipecolic acid, and its 3-hydroxy derivatives from furan derived common chiral bicycloaziridino lactone synthon is described here. Key features are the short (4-steps), enantiopure, and decagram-scale synthesis of common chiral synthon from furan and its first-ever application in the total synthesis of biologically active compounds by taking the advantages of high functionalization ability of chiral synthon.

}, keywords = {Aziridine synthon, Chiral auxiliary, collective synthesis, Pipecolic acid, Tamiflu}, issn = {1861-4728}, doi = {10.1002/asia.201901523, Early Access Date = JAN 2020}, author = {Chavan, Subhash P. and Kadam, Appasaheb L. and Shinde, Shrikrishna S. and Gonnade, Rajesh G.} } @article {46634, title = {Scalable synthesis of 3-Ethyl-4-methyl-1,5-dihydro-2H-pyrrol-2-one: an important building block of the antidiabetic drug glimepiride}, journal = {Synthesis-Stuttgart}, volume = {52}, year = {2020}, month = {NOV}, pages = {3480-3484}, type = {Article}, abstract = {

A four-step, practical, and easily scalable synthesis of 3-ethyl-4-methyl-1,5-dihydro-2H-pyrrol-2-one, an important building block of the antidiabetic drug glimepiride, has been accomplished. Key features are the synthesis of 3-methyl-4-hydroxy-2-butenolide in water and triflic acid mediated N-benzyl lactam N-deprotection. The main advantages of this process are the scalable synthetic route and decreased number of reaction steps, which paves the way for the industrial-scale synthesis of 3-ethyl-4-methyl-1,5-dihydro-2H-pyrrol-2-one.

}, keywords = {antidiabetic drug, Butenolide, glimepiride, lactams, scalable synthesis}, issn = {0039-7881}, doi = {10.1055/s-0040-1707344}, author = {Chavan, Subhash P. and Pawar, Ambaji A. and Patil, Niteen B. and Kadam, Appasaheb L. and Shinde, Shrikrishna S.} } @article {47349, title = {Application of allylic amine formation from aziridine-2-ol under appel reaction condition: synthesis of N-(tert-butoxycarbonyl)-D-vinyl glycine methyl ester}, journal = {Tetrahedron Letters}, volume = {73}, year = {2021}, month = {JUN }, pages = {153119}, type = {Article}, abstract = {

PPh3/I-2/imidazolde mediated allyl amine formation from aziridine-2-alcohol was explored for the synthesis of N-(tert-butoxycarbonyl)-D-vinyl glycine methyl ester. (C) 2021 Published by Elsevier Ltd.

}, keywords = {Allyl amine, Aziridine-2-alcohol, Aziridinium ion, Birch reaction, Ring opening}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2021.153119}, author = {Chavan, Subhash P. and Kawale, Sanket A. and Patil, Niteen B. and Kalbhor, Dinesh B.} } @article {47097, title = {Divergent approach to the synthesis of (-)-balanol heterocycle and cis-3-hydroxypipecolic acid based on chiral 2-aminoalkanol equivalent}, journal = {Tetrahedron}, volume = {80}, year = {2021}, month = {JAN}, pages = {131773}, type = {Article}, abstract = {

Enantioselective synthesis of the hexahydroazepine core of (-)-balanol and formal synthesis of cis-3hydroxypipecolic acid from a common intermediate have been accomplished by a divergent path. The common intermediate was accessed from a favorably protected enantiomerically pure 2-amino-1,3,4-butanetriol (ABT) equivalent via oxidation and Wittig olefination. The synthesis of (-)-balanol heterocycle featured tandem reduction/acetal-deprotection/gamma-lactonization reaction and a one-pot azide reduction followed by seven membered aza-heterocycle formation while the route to cis-3-hydroxypipecolic acid highlighted the base induced piperidine ring formation and regioselective benzylidine-acetal cleavage. (C) 2020 Elsevier Ltd. All rights reserved.

}, keywords = {Amino-alcohol, desymmetrization, Hexahydroazepine, Piperidine alkaloids, Protein kinase}, issn = {0040-4020}, doi = {10.1016/j.tet.2020.131773}, author = {Chavan, Subhash P. and Kalbhor, Dinesh B. and Gonnade, Rajesh G.} } @article {47664, title = {Formal synthesis of (-)-quinagolide: diastereoselective ring expansion via a bicyclic aziridinium ion strategy to access the octahydrobenzo[g]quinoline architecture}, journal = {Journal of Organic Chemistry}, volume = {86}, year = {2021}, month = {JUL }, pages = {9344-9352}, type = {Article}, abstract = {The diastereoselective formal synthesis of (-)-quinagolide, a D-2 receptor agonist, has been achieved. The synthesis started from L-pyroglutamic acid and relied on utilization of (a) a stereospecific catalytic hydrogenation and diastereoselective Horner-Emmons-Michael cascade to obtain functionalized prolinate, (b) a Lewis acid mediated Pummerer cyclization to construct a tricyclic fused ring system, and (c) a diastereoselective ring expansion via a bicyclic aziridinium intermediate to access the required 3-substituted piperidine scaffold.}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c00603}, author = {Chavan, Subhash P. and Kawale, Sanket A. and Pisal, Mahesh M. and Kadam, Appasaheb L. and Gonnade, Rajesh G.} } @article {47615, title = {Multi-step synthesis of miltefosine: integration of flow chemistry with continuous mechanochemistry}, journal = {Chemistry-A European Journal}, volume = {27}, year = {2021}, month = {DEC }, pages = {17695-17699}, type = {Article}, abstract = {Herein we report for the first time, an advanced continuous flow synthesis of the blockbuster Leishmaniasis drug miltefosine from simple starting materials by a sequence involving four steps of chemical transformation including a continuous mechanochemical step. First three reaction steps were performed in simple tubular reactors in a telescopic mode, while in the last step the product precipitated from the 3(rd) step was used for a continuous mechanochemical synthesis of miltefosine. When compared to a typical batch protocol that takes 15 h, miltefosine was obtained in 58 \% overall yield in flow synthesis mode at the laboratory scale in a total residence time 34 min at synthesis rate of 10 g/hr, which is sufficient to treat 4800 patients per day.}, keywords = {continuous flow, continuous mechanochemistry, miltefosine, multistep synthesis, reactive intermediates}, issn = {0947-6539}, doi = {10.1002/chem.202103499}, author = {Patil, Niteen B. and Atapalkar, Ranjit S. and Chavan, Subhash P. and Kulkarni, Amol A.} } @article {47108, title = {Synthesis and cell imaging applications of fluorescent mono/di/tri-heterocyclyl-2,6-dicyanoanilines (vol 27, pg 979, 2017)}, journal = {Bioorganic \& Medicinal Chemistry Letters}, volume = {32}, year = {2021}, month = {JAN }, pages = {127737}, type = {Correction}, issn = {0960-894X}, doi = {10.1016/j.bmcl.2020.127737}, author = {Pisal, Mahesh M. and Annadate, Ritesh A. and Athalye, Meghana C. and Kumar, Deepak and Chavan, Subhash P. and Sarkar, Dhiman and Borate, Hanumant B.} } @article {48009, title = {cis-aziridine synthon based synthetic investigation for tamiflu employing horner-wadsworth-emmons reaction}, journal = {European Journal of Organic Chemistry}, volume = {2022}, year = {2022}, month = {JUL }, pages = {e202200384}, type = {Article}, abstract = {

Synthetic investigations to achieve a novel intermediate of Tamiflu by using cis-aziridine as a chiral building block, which is readily synthesized from (D)-mannitol as a renewable starting material, has been presented. The present approach utilizes the intramolecular Horner-Wadsworth-Emmons reaction as the key step for the synthesis of Tamiflu. On the other hand, diene containing allylic aziridine framework is found to be inefficient to furnish the six-membered core skeleton of Tamiflu through ring-closing metathesis reaction.

}, keywords = {Aziridine, cyclization, HWE reaction, Metathesis, Tamiflu}, issn = {1434-193X}, doi = {10.1002/ejoc.202200384}, author = {Chavan, Subhash P. and Kawale, Sanket A. and Gonnade, Rajesh G.} } @article {48006, title = {Rapid synthesis of the epi-biotin sulfone via tandem S,N-carbonyl migration/aza-michael/spirocyclization and haller-bauer reaction}, journal = {ACS Omega}, volume = {7}, year = {2022}, month = {MAY }, pages = {17215-17222}, type = {Article}, abstract = {

A synthesis of 2-epi-biotin sulfone was accomplished from commercially available L-cysteine. The synthesis features an unprecedented tandem S,N-carbonyl migration/aza-Michael/spirocyclization reaction from an L-cysteine-derived enone with aq. ammonia, in which three new sigma bonds and two rings are formed. In addition, the synthesis includes a highly diastereoselective late-stage Haller-Bauer reaction of sulfone for direct introduction of the carbon side chain.

}, issn = {2470-1343}, doi = {10.1021/acsomega.2c01030}, author = {Chavan, Subhash P. and Kalbhor, Dinesh B. and Gonnade, Rajesh G.} } @article {48075, title = {Revisiting classical pummerer cyclization reaction: a key strategy for the synthesis of (+/-)-quinagolide}, journal = {ChemistrySelect}, volume = {7}, year = {2022}, month = {JUL}, pages = {e202201600}, type = {Article}, abstract = {

A formal synthesis of (+/-)-quinagolide using beta-alanine as a starting material has been achieved. Late stage intramolecular classical Pummerer reaction has been used as a key synthetic tool to construct octahydrobenzo[g]quinoline skeleton of quinagolide. Conjugative reduction of olefin, regioselective C-alkylation over O-alkylation of beta-ketoester followed by retro-Dieckmann/ Dieckmann reaction sequence has been used as a key reaction sequence to achieve prerequisite sulfoxide for the Pummerer reaction. While revisiting the classical Pummerer reaction, the one-pot sequential thionium ion induced cyclocarbamation followed by N-carbamate deprotection and Friedel-Crafts type Pummerer cyclization was observed as an important finding of the present work.

}, keywords = {Alkylation, Cyclocarbamation, Hyperprolactinemia, rearrangement, Thionium ion}, issn = {2365-6549}, doi = {10.1002/slct.202201600}, author = {Chavan, Subhash P. and Kawale, Sanket A. and Tripathi, Anupam and Kadam, Appasaheb L. and Gonnade, Rajesh G.} } @article {48718, title = {Rapid bioinspired N-acyliminium ion strategy for the ABC core of the stemona alkaloids}, journal = {Asian Journal of Organic Chemistry}, volume = {12}, year = {2023}, month = {SEP}, type = {Article}, abstract = {

A concise and highly diastereoselective bioinspired key cationic cyclization strategy for the asymmetric synthesis of the tricyclic core of the (-)-stemoamide, together with 8,9-bis-epi-stemoamide has been described. The key N-acyliminium ion precursors were accessed from L-tartaric acid and L-malic acid respectively. The use of ethyl acetoacetate derived bifunctional allylidenetriphenylphosphorane reagent in the early stage of the synthetic strategy is advantageous for the rapid construction of highly functionalized key pyrrolo[1,2-\& alpha;]azepine frameworks.

}, keywords = {alkaloids, Biomimetic synthesis, Claisen rearrangement, cyclization, Regioselectivity}, issn = {2193-5807}, doi = {10.1002/ajoc.202300331}, author = {Chavan, Subhash P. and Kalbhor, Dinesh B. and Gonnade, Rajesh G.} }