@article { ISI:000229484400013, title = {Synthesis of naturally occurring bioactive butyrolactones: maculalactones A-C and nostoclide I}, journal = {Tetrahedron}, volume = {61}, number = {22}, year = {2005}, month = {MAY}, pages = {5297-5302}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Starting from citraconic anhydride (13), a simple multistep (9-10 steps) synthesis of naturally occurring butyrolactones maculalactone A (3), maculalactone B (1), maculalactone C (2) and nostoclide 1 (4) have been described with good overall yields via dibenzylmaleic anhydride (20) and benzylisopropylmaleic anhydride (27). The two anhydrides 20 and 27 were prepared by S(N)2{\textquoteright} coupling reactions of appropriate Grignard reagents with dimethyl bromomethylfumarate (14), LiOH-induced hydrolysis of esters to acids, bromination of carbon-carbon double bond, in situ dehydration followed by dehydrobromination and chemoselective allylic substitution of bromoatom in disubstituted anhydrides 19 and 26 with appropriate Grignard reagents. The NaBH4 reduction of these anhydrides 20 and 27 furnished the desired lactones 21 and 29, respectively. The lactone 21 on Knoevenagel condensation with benzaldehyde, furnished maculalactone B (1), which on isomerization gave maculalactone C (2). Selective catalytic hydrogenation of 1 gave maculalactone A (3). The conversion of lactone 29 to nostoclide 1 (4) is known. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {dimethyl bromomethylfumarate, disubstituted maleic anhydrides, maculalactone A-C, NaBH4 reductions, nostoclide 1, S(N)2 {\textquoteleft} Grignard couplings, synthesis}, issn = {0040-4020}, doi = {10.1016/j.tet.2005.03.065}, author = {Kar, Anirban and Gogoi, Sanjib and N. P. Argade} } @article { ISI:000241064000001, title = {Chemistry of recently isolated naturally occurring quinazolinone alkaloids}, journal = {Tetrahedron}, volume = {62}, number = {42}, year = {2006}, month = {OCT}, pages = {9787-9826}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The present review portrays a concise account of the isolation, bioactivity, and synthesis of bioactive quinazolinone-based natural products for the period 1983-2005 and the recent developments in the area of complex quinazolinone natural products with a special emphasis on new synthetic routes and strategies. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {1983-2005, bioactivity, concise account, isolation, natural quinazolinones, synthesis}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.07.098}, author = {Mhaske, Santosh B. and N. P. Argade} } @article { ISI:000236256600002, title = {Facile two-step chemoenzymatic access to natural germination inhibitor (+)-erigeronic acid A}, journal = {Tetrahedron}, volume = {62}, number = {13}, year = {2006}, month = {MAR}, pages = {2999-3003}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A facile two-step synthesis of natural germination inhibitor 5-butyl-3-oxo-2,3-dihydrofuran-2-yl-acetic acid [(+)-erigeronic acid A, 1] has been described via highly regioselective ring opening of (R)-acetoxysuccinic anhydride with the primary enolate of butyl methyl ketone, followed by an enzymatic hydrolysis and ail in situ dehydrative cyclization pathway with 77\% overall yield. Oil the basis of the present chemoenzymatic approach, (R)-configuration has been assigned to the C-2 chiral centre of the natural erigeronic acid. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {(+)-erigeronic acid, (R)acetoxysuccinic anhydride, natural germination inhibitor, primary enolate of butyl methyl ketone, synthesis}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.01.044}, author = {Gogoi, Sanjib and N. P. Argade} } @article { ISI:000246320900026, title = {Hexamethyldisilazane-iodine induced intramolecular dehydrative cyclization of diamides: a general access to natural and unnatural quinazolinones}, journal = {Tetrahedron Letters}, volume = {48}, number = {18}, year = {2007}, month = {APR}, pages = {3243-3246}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple and efficient general approach to various quinazolinone scaffolds, including peptidomimetic examples, has been demonstrated by employing HMDS/I-2 for the intramolecular dehydrative cyclization of diamides. The protecting groups -Boc, -Fmoc and -Cbz tolerated the present reaction conditions and we did not observe any racemization. The present protocol has also been used as a key step for the efficient four-step syntheses of the naturally occurring quinazolinones, sclerotigenin, (-)-circumdatin-F and (-)-fumiquinazoline-F. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {diamides, HMDS/I-2, intramolecular dehydrative cyclizations, natural and unnatural quinazolinones, synthesis}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2007.03.032}, author = {Kshirsagar, Umesh A. and Mhaske, Santosh B. and N. P. Argade} } @article { ISI:000281130600002, title = {General approach to 2,4-dialkyl-3-carboxybutyrolactones: an efficient synthesis of (+/-)-striatisporolide A and (+/-)-lichesterinic acid}, journal = {Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry}, volume = {49}, number = {8, SI}, year = {2010}, month = {AUG}, pages = {1071-1075}, publisher = {COUNCIL SCIENTIFIC \& INDUSTRIAL RES}, address = {ANUSANDHAN BHAWAN, 2 RAFI MARG, NEW DELHI, 110001, INDIA}, abstract = {

Starting from 2-alkylidene-3-methylsuccinimides, simple and efficient synthesis of the natural products striatisporolide A. lichesterinic acid and lichesterylic acid have been demonstrated via an acid catalyzed hydrolysis, esterification, OsO(4)-dihydroxylation and dehydrative cyclization pathway.

}, keywords = {2-Alkylidene-3-methylsuccinimides, dehydrative cyclizations, lichesterinic acid, OsO(4)-dihydroxylation, striatisporolide A, synthesis}, issn = {0376-4699}, author = {Patel, Ramesh M. and N. P. Argade} } @article { ISI:000291960800006, title = {Regioselective NaBH4 and DIBAL-H reductions of 3,4-dimethoxyhomopiperonylphthalimide: concise and efficient synthesis of nuevamine and isonuevamine}, journal = {Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry}, volume = {50}, number = {6}, year = {2011}, month = {JUN}, pages = {868-871}, publisher = {COUNCIL SCIENTIFIC \& INDUSTRIAL RES}, address = {ANUSANDHAN BHAWAN, 2 RAFI MARG, NEW DELHI, 110001, INDIA}, abstract = {

Facile synthesis of nuevamine and isonuevamine has been reported via the regioselectivc reduction of hindered and unhindered carbonyl groups of 3,4-dimethoxyhomopiperonylphthalimide, respectively using sodium borohydridc and diisobutylaluminum hydride, Mowed by an acid catalyzed intramolecular dehydrative cyclization pathways. The chemistry involved in obtaining the regioselectivity has been discussed in brief.

}, keywords = {6-dimethoxyhomophthalimide, intramolecular dehydrative cyclizations, isonuevamine, N-Homopiperonyl-5, nuevamine, regioselective reductions, synthesis}, issn = {0376-4699}, author = {Wakchaure, Prasad B. and Kunte, Sunita S. and N. P. Argade} } @article { ISI:000325264400010, title = {Biology-orientated synthesis of putrescine bisamides gigantamide A, dasyclamide, and cucullamide}, journal = {Synthesis-Stuttgart}, volume = {45}, number = {20}, year = {2013}, month = {OCT}, pages = {2888-2892}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Starting from putrescine and the requisite carboxylic acids, first syntheses of bioactive natural products gigantamide A, dasyclamide, and cucullamide were accomplished in very good overall yields using an appropriate sequence of dehydrative coupling reactions. The syntheses of the corresponding dehomo analogues of these natural products are also described. Regioselective diisobutylaluminum hydride reduction of an unhindered carbonyl group in citraconimide is the key step.

}, keywords = {dehydrative coupling reactions, diamines, natural and unnatural bisamides, regioselective reduction, synthesis}, issn = {0039-7881}, doi = {10.1055/s-0033-1339658}, author = {Batwal, Ramesh U. and N. P. Argade} } @article { ISI:000336838100008, title = {Metal-catalyzed cross-coupling reactions of halomaleic anhydrides and halomaleimides: synthesis of structurally interesting and biologically important natural and unnatural products}, journal = {Synthesis-Stuttgart}, volume = {46}, number = {3}, year = {2014}, month = {FEB}, pages = {281-289}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

This brief review presents a concise literature account of the metal-catalyzed cross-coupling reactions of halomaleic anhydrides and halomaleimides leading to significant synthetic and natural products. Metal-catalyzed Heck, Suzuki-Miyaura, Stille-Migita, Negishi, Hiyama, and Sonogashira cross-coupling reactions with palladium as the key element are discussed. The metal-catalyzed exchange of a vinylic leaving group by a carbon nucleophile, the SNV reaction, gives a diverse range of bioactive natural and unnatural products.

}, keywords = {bioactive natural and unnatural products, halomaleic anhydride, halomaleimide, metal-catalyzed cross-coupling, synthesis}, issn = {0039-7881}, doi = {10.1055/s-0033-1338579}, author = {Deore, Prashant S. and N. P. Argade} } @article { ISI:000341070100010, title = {Synthesis of chenopanone}, journal = {Indian Journal of Chemistry Section B-Organic Chemistry Including Medicinal Chemistry}, volume = {53}, number = {8}, year = {2014}, month = {AUG}, pages = {1140-1142}, publisher = {COUNCIL SCIENTIFIC \& INDUSTRIAL RES}, address = {ANUSANDHAN BHAWAN, 2 RAFI MARG, NEW DELHI, 110001, INDIA}, abstract = {

Starting from glyoxalic acid, a facile three step approach to chenopanone has been described utilizing the Barbier reaction as a key step.

}, keywords = {acid hydrolysis, Barbier reaction, chenopanone, condensation, Glyoxalic acid, isovaleraldehyde, synthesis}, issn = {0376-4699}, author = {Deore, Prashant S. and N. P. Argade} }