Publications by authors named "P Nagender"

Direct access to pharmaceutically attractive benzo-fused nine-membered heterocyclic alkenes with a trifluoromethyl carbinol moiety was achieved a palladium-catalyzed double-decarboxylative formal ring-expansion process from six-membered trifluoromethyl benzo[][1,3]oxazinones to nine-membered trifluoromethyl benzo[][1,5]oxazonines in the presence of vinylethylene carbonates . Generation of a Pd-π-allyl zwitterionic intermediate was proposed in the catalytic cycle. The trifluoromethyl group in the benzoxazinanones plays an important role throughout the transformation.

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A series of novel nicotinohydrazide derivatives 6a-g and 1,3,4-oxadiazole functionalized pyridine derivatives 7a-k and 8a-d were prepared in series of steps. All the compounds were screened for cytotoxicity against HeLa (cervical), DU145 (prostate), HepG2 (liver) and MBA-MB-231 (breast) human cancer cell lines. Compounds 6h, 6i, 7d, 7h, 7i and 8b which showed promising cytotoxicity at <15μM concentration have been identified.

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A series of novel pyrazolo[3,4-b]pyridine based target compounds were synthesized starting from the key intermediate ethyl 2-(3-amino-6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-1-yl)acetate 5 on reaction with hydrazine hydrate followed by reaction with different aldehydes, acid chlorides and isothiocyanates to form hydrazones 7, oxadiazoles 8, 1,2,4 triazoles 10 and thiadiazoles 11 respectively in high yield. All the final compounds were screened for anticancer activity against four human cancer cell lines. Among them, 1,2,4 triazole derivatives showed promising activity and compound 10d is identified as a lead molecule.

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A series of novel trifluoromethyl substituted furo[2,3-b]pyridine and pyrido[3',2':4,5]furo[3,2-d] pyrimidine derivatives 3a-b, 6a-k, 9, 10a-b, 11a-c and 12a-c were prepared from 2-carbethoxy-3-amino-6-trifluoromethyl furo[2,3-b]pyridine 1 under different set of conditions. Compounds functionalized with oxadiazole 11a-c were also prepared from 2-carbohydrazide-3-amino-6-trifluoromethyl furo[2,3-b]pyridine 4. All the final products were screened for anticancer activity against four human cancer cell lines such as Neuro-2a, Hela, A549 and COLO 205 as well as normal human lung cell line, IMR-90.

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A series of novel pyrazolo[3,4-b]pyridine and pyrimidine functionalized 1,2,3-triazole derivatives 8a-g and 9a-g were prepared starting from 6-trifluoromethylpyridine-2(1H)one 2 via selective O-alkylation, followed by cyclisation using hydrazine hydrate to obtain 6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine 4. Compound 4 was diazotized followed by reaction with sodium azide, resulted in 3-azido-6-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridine 5. Compound 5 was further cyclized with N-/O-propargylated pyrimidine derivatives under Sharpless conditions and obtained compounds 6 and 7, respectively.

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