@article { ISI:000260843700019, title = {Total synthesis of (+)-isolaurepan}, journal = {Tetrahedron Letters}, volume = {49}, number = {49}, year = {2008}, month = {DEC}, pages = {7012-7014}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A versatile and efficient method for the enantioselective synthesis of 2,7-cis-disubstituted oxepane 1c, (+)-isolaurepan, using oxidative resolution of a secondary alcohol and highly diastereoselective Et(3)SiH/TMSOTf-promoted reductive cyclization of a hydroxy ketone is described. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Cis-selective cyclization, Cyclic ethers, Isolaurepan, Oxepanes, Oxidative resolution of secondary alcohols}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2008.09.134}, author = {Tripathi, Divya and Kumar, Pradeep} } @article { ISI:000264471400009, title = {General approach to medium-sized ring ethers via hydrolytic and oxidative kinetic resolutions: stereoselective syntheses of (-)-cis-lauthisan and (+)-isolaurepan}, journal = {Tetrahedron}, volume = {65}, number = {11}, year = {2009}, month = {MAR}, pages = {2226-2231}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A short and enantioselective approach to medium ring ethers and its application to the syntheses of (-)-cis-lauthisan and (+)-isolaurepan are described. The synthetic strategy features Jacobson{\textquoteright}s Hydrolytic Kinetic Resolution (HKR), oxidative resolution of secondary alcohol, and highly diastereoselective Et(3)SiH/TMSOTf-promoted reductive cyclization of a hydroxy ketone to give exclusively the different medium-sized cis-disubstituted cyclic ethers. (C) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {cis-Reductive cyclization, Jacobson{\textquoteright}s Hydrolytic Kinetic Resolution (HKR), Oxepanes, Oxidative resolution of secondary alcohol, Ring ether}, issn = {0040-4020}, doi = {10.1016/j.tet.2009.01.062}, author = {Tripathi, Divya and Pandey, Satyendra Kumar and Kumar, Pradeep} } @article { ISI:000298534500008, title = {Organocatalytic route to the synthesis of (6S)-5,6-dihydro-6-[(2R)-2-hydroxy-6-phenylhexyl]-2H-pyran-2-one and ravensara lactones}, journal = {Tetrahedron-Asymmetry}, volume = {22}, number = {18-19}, year = {2011}, month = {OCT}, pages = {1749-1756}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

An organocatalytic enantioselective synthesis of the title compounds has been achieved. The stereogenic centers were generated by the iterative use of proline catalyzed alpha-aminoxylations and HWE olefination of aldehydes while the lactone ring was constructed by ring closing metathesis. (C) 2011 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2011.09.017}, author = {Dwivedi, Namrata and Tripathi, Divya and Kumar, Pradeep} } @article { ISI:000307433600011, title = {Formal synthesis of tetrahydrolipstatin and tetrahydroesterastin}, journal = {Tetrahedron-Asymmetry}, volume = {23}, number = {11-12}, year = {2012}, month = {JUN}, pages = {884-890}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A versatile and efficient approach to (3.5,5R)-methyl 3-(benzyloxy)-5-(methoxymethoxy)hexadecanoate, a key chiral building block and a common polyol fragment of the anti-tumor and anti-obesity agents tetrahydrolipstatin 3 and tetrahydroesterastin 4 using both hydrolytic kinetic resolution (HKR) and proline catalyzed sequential alpha-aminoxylation, followed by HWE-olefination reaction is described. (c) 2012 Elsevier Ltd. All rights reserved.

}, issn = {0957-4166}, doi = {10.1016/j.tetasy.2012.05.025}, author = {Tripathi, Divya and Kumar, Pradeep} } @article { ISI:000325642800010, title = {Production, purification and characterization of cholesterol oxidase from a newly isolated streptomyces sp.}, journal = {World Journal of Microbiology \& Biotechnology}, volume = {29}, number = {11}, year = {2013}, month = {NOV}, pages = {2077-2085}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Cholesterol oxidase production (COD) by a new isolate characterized as Streptomyces sp. was studied in different production media and fermentation conditions. Individual supplementation of 1 \% maltose, lactose, sucrose, peptone, soybean meal and yeast extract enhanced COD production by 80-110 \% in comparison to the basal production medium (2.4 U/ml). Supplementation of 0.05 \% cholesterol (inducer) enhanced COD production by 150 \%. COD was purified 14.3-fold and its molecular weight was found to be 62 kDa. V-max (21.93 mu M/min mg) and substrate affinity K-m (101.3 mu M) suggested high affinity of the COD for cholesterol. In presence of Ba2+ and Hg2+ the enzyme activity was inhibited while Cu2+ enhanced the activity nearly threefold. Relative activity of the enzyme was found maximum in triton X-100 whereas sodium dodecyl sulfate inactivated the enzyme. The enzyme activity was also inhibited by the thiol-reducing reagents like Dithiothreitol and beta-mercaptoethanol. The COD showed moderate stability towards all organic solvents except acetone, benzene and chloroform. The activity increased in presence of isopropanol and ethanol. The enzyme was most active at pH 7 and 37 A degrees C temperature. This organism is not reported to produce COD.

}, keywords = {Affinity chromatography, Cholesterol oxidase, HPLC, SDS PAGE, Streptomyces sp.}, issn = {0959-3993}, doi = {10.1007/s11274-013-1371-8}, author = {Niwas, Ram and Singh, Vineeta and Singh, Rajbir and Tripathi, Divya and Tripathi, C. K. M.} } @article { ISI:000357723600001, title = {Isolation, characterization and antifungal docking studies of wortmannin isolated from penicillium radicum}, journal = {Scientific Reports}, volume = {5}, year = {2015}, month = {JUL}, pages = {Article Number: 11948}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {

During the search for a potent antifungal drug, a cell-permeable metabolite was isolated from a soil isolate taxonomically identified as Penicillium radicum. The strain was found to be a potent antifungal agent. Production conditions of the active compound were optimized and the active compound was isolated, purified, characterized and identified as a phosphoinositide 3-kinase (PI3K) inhibitor, commonly known as wortmannin (Wtmn). This is very first time we are reporting the production of Wtmn from P. radicum. In addition to its previously discovered anticancer properties, the broad spectrum antifungal property of Wtmn was re-confirmed using various fungal strains. Virtual screening was performed through molecular docking studies against potential antifungal targets, and it was found that Wtmn was predicted to impede the actions of these targets more efficiently than known antifungal compounds such as voriconazole and nikkomycin i.e. 1) mevalonate-5-diphosphate decarboxylase (1FI4), responsible for sterol/isoprenoid biosynthesis; 2) exocyst complex component SEC3 (3A58) where Rho-and phosphoinositide-dependent localization is present and 3) Kre2p/Mnt1p a Golgi alpha1,2-mannosyltransferase (1S4N) involved in the biosynthesis of yeast cell wall glycoproteins). We conclude that Wtmn produced from P. radicum is a promising lead compound which could be potentially used as an efficient antifungal drug in the near future after appropriate structural modifications to reduce toxicity and improve stability.

}, issn = {2045-2322}, doi = {10.1038/srep11948}, author = {Singh, Vineeta and Praveen, Vandana and Tripathi, Divya and Haque, Shafiul and Somvanshi, Pallavi and Katti, S. B. and Tripathi, C. K. M.} } @article {43485, title = {Transition metal catalysis-a unique road map in the stereoselective synthesis of 1,3-polyols}, journal = {Organic \& Biomolecular Chemistry}, volume = {15}, year = {2017}, month = {JAN}, pages = {733-761}, abstract = {The present review summarizes recent diverse reactions employed in the formation of 1,3-polyols providing an overview of the mechanistic pathway and the enantioselectivity obtained, in terms of the properties of transition metals directly involved in the catalytic transformations and their interaction with various ligands.}, doi = {10.1039/c6ob01925k}, author = {Kumar, Pradeep and Tripathi, Divya and Sharma, Brijesh M. and Dwivedi, Namrata} }