http://nopr.niscpr.res.in/handle/123456789/310 Fri, 09 Oct 2026 14:07:18 GMT 2026-10-09T14:07:18Z http://nopr.niscpr.res.in/handle/123456789/474 Title: Synthesis of novel 1,2,4-oxadiazole heterocyclic compounds containing 2-H pyranopyridine-2-one moiety and related compounds Authors: Kumar, N Vasanth; Mashelker, Uday C Abstract: 7-Hydroxy/Amino-5-methyl-6-(5-substituted-[1,2,4]oxadiazol-3-yl)-2-oxo-2H-pyrano[2,3-b]pyridine-3-carboxylic acid amides 5a-c and 6a-c have been prepared starting from ethyl 2H-pyrano [2,3-b] pyridine-3-carboxylate 1 and 2, compounds 1 and 2 are treated with aqueous ammonia solution to afford 2H-pyrano[2,3-b] pyridine-3-carboxamide 3a-b, which are converted to 6-carboxamidoxime 2H-pyrano [2,3-b] pyridine-3-carboxamide 4a-b by treating with hydroxyl amine in refluxing ethanol. Carboxamidoximes 4a-b are treated with various acid chlorides to obtain 1,2,4-oxadiazole derivatives 5a-c and 6a-c. Carboxamide 3a is reacted with triethyl orthoformate to give 4-amino-5-methyl pyrano [3",2':5,6] pyrido [2,3-d] pyrimidine-7-carboximde 7. Carboxamidoxime 4a is allowed to react with N,N-dimethyl formamide dimethyl acetal under reflux to obtain N-(6-carbonyl-4-methyl-7-oxo-1,7-dihydropyrano[2,3-b]pyrazolo[4,3-e]pyri¬dine-3-yl)methanamide 8. These compounds are expected to have better hypertensive activity. Page(s): 216-220 Mon, 01 Jan 2007 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/474 2007-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/472 Title: A novel synthesis of spiroisoxazoles via 1,3-dipolar cycloaddition of nitrile oxide to 6-arylidene 6,7,8,9- tetrahydrobenzo¬cyclohepten-5-one Authors: Venkateswarlu, Peesapati; Vasireddy, Nageswara Rao Abstract: Synthesis of a series of spiroisoxazole derivatives have been accomplished in good yield by regioselective 1,3-dipolar cycloaddition of nitrile oxide to 6-arylidene-3-methyl-6,7,8,9-tetrahydro-5H-benzo[a]cyclohepten-5-one. The antimicrobial activity of these compounds have been carried out. Page(s): 213-215 Mon, 01 Jan 2007 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/472 2007-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/471 Title: Microwave-assisted facile synthesis of a new class of asymmetrical diheteroarylmethanes bearing imidazopyridine moieties under solvent-free condition Authors: Duan, Guiyun; Sun, Yawei; Liu, Junzhi; Zhao, Guilong; Zhang, Datong; Wang, Jianwu Abstract: Microwave-assisted facile condensation of ethyl 2-benzimidazoleacetates or ethyl 2-benzothiazoleacetates with o-diaminopyridines under solvent-free condition has afforded asymmetric diheteroarylmethanes in excellent yields. The synthetic route is optimized and all the reported compounds are fully characterized. Page(s): 210-212 Mon, 01 Jan 2007 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/471 2007-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/469 Title: Microwave assisted synthesis of N-(3-aryl-1,8-naphthyridin-2-yl) phthalimides under solvent-free conditions Authors: Mogilaiah, K; Sakram, B Abstract: A simple, rapid and efficient protocol for the synthesis of N-(3-aryl-1,8-naphthyridin-2-yl)phthalimides 3 has been achieved by the reaction of 2-amino-3-aryl-1,8-naphthyridines 1 with phthalic anhydride 2 in the presence of catalytic amount of DMF under microwave irradiation. Page(s): 207-209 Mon, 01 Jan 2007 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/469 2007-01-01T00:00:00Z