NISCAIR Online Periodicals Repository Collection: IJC-B Vol.48B(12) December 2009]

Weinreb amide based building blocks for convenient access to various synthetic targets

Sat, 28 Nov 2009 22:58:59 GMT

Title: Weinreb amide based building blocks for convenient access to various synthetic targets

Authors: Sivaraman, B; Manjunath, B N; Senthilmurugan, A; Harikrishna, K; Singh, Aidhen Indrapal

Abstract: N-Methoxy-N-methylamide, popularly known as the Weinreb amide (WA), has served as an excellent acylating agent for organolithium and/or organomagnesium reagents and a robust equivalent for an aldehyde group. The stability of the WA functionality, its ease of preparation, the scalability of its reactions and its predictable reactivity are the key features responsible for its prominent use in several synthetic endeavors by the chemists world-wide. The development of WA-based building blocks and synthetic equivalents for interesting synthons has been a long drawn pursuit initiated in nineties and through this mini-review accomplishments in this direction, with particular emphasis on the building blocks, developed recently in the last three years are summarized.

Page(s): 1749-1756

Synthesis and lipase-catalysed enantioselective acylation studies on ethyl 4-aryl-3,4-dihydropyrimidin-2(1H)-ones

Sat, 28 Nov 2009 22:58:59 GMT

Title: Synthesis and lipase-catalysed enantioselective acylation studies on ethyl 4-aryl-3,4-dihydropyrimidin-2(1H)-ones

Authors: Prasad, Ashok K; Arya, Pragya; Bhatia, Sumati; Sharma, Raman K; Singh, Rishipal; Singh, Brajendra K; Eycken, Erik Van der; Singh, Rajpal; Olsen, Carl E; Parmar, Virinder S

Abstract: A series of different analogs of 4-aryl-3,4-dihydropyrimidin-2(1H)-one have been synthesized and their biocatalytic resolution has been carried out using immobilized lipase CAL-L(A) (immobilized on accurel). The systematic one-step procedure is developed for the synthesis of optically enriched ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylates 8a-d and acylated ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylates 9a-e, 10a-e, 11b-d and 12a-e, by the enantioselective acylation of racemic ethyl 4-aryl-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylates using CAL-L(A).

Page(s): 1738-1748

Synthesis and studies on antimicrobial, antiinflammatory and antiproliferative activities of heterocycles derived from 4-/5-/6-/7-nitro/5-fluoro/chloro/bromoindole-2-carbohydrazides

Sat, 28 Nov 2009 22:58:59 GMT

Title: Synthesis and studies on antimicrobial, antiinflammatory and antiproliferative activities of heterocycles derived from 4-/5-/6-/7-nitro/5-fluoro/chloro/bromoindole-2-carbohydrazides

Authors: Narayana, B; Ashalatha, B V; Raj, K K Vijaya; Sarojini, B K

Abstract: Synthesis and studies on antimicrobial, antiinflammatory and antiproliferative activities of heterocycles derived from 4-/5-/6-/7-nitro/5-fluoro/chloro/bromoindole-2-carbohydrazides are discussed. 4-/5-/6-/7-nitroindole-2-carbohydrazides and 5-fluoro/chloro/bromoindole-2-carbohydrazides on treatment with acetyl acetone in methanol have resulted in 2-[(3,5-dimethyl-1H-pyrazol-1-yl)carbonyl]-4-/5-/6-/7-nitro-1H-indoles and 2-[(3,5-dimethyl-1H-pyrazol-1-yl) carbonyl]-5-fluoro/chloro/bromo-1H-indoles respectively. 4-/6-/7-nitroindole-2-carbohydrazides on treatment with CS₂/KOH in methanol have yielded 5-(4-/6-/7-nitro-1H-indol-2-yl)-1,3,4-oxadiazole-2-thiol and with cyanogen bromide yielded 5-(4-/6-/7-nitro-1H-indol-2-yl)-1,3,4-oxadiazol-2-amine. Nitroindole-2-carbohydrazides are also treated with various aromatic carboxylic acids and triethyl orthoformate yielded 2-[5-(aryl)-1,3,4-oxadiazol-2-yl]-4-/5-/6-/7-nitro-1H-indoles and 4-/6-/7-nitro-2-(1,3,4-oxadiazol-2-yl)-1H-indoles, respectively. Structures of the newly synthesized compounds are characterized by analytical and spectral data.

Page(s): 1794-1805

Synthesis and antimicrobial activity of 5-(2-aminothiazol-4-yl)-3, 4-dihydro-4-phenyl pyrimidin-2(1H)-one

Sat, 28 Nov 2009 22:58:59 GMT

Title: Synthesis and antimicrobial activity of 5-(2-aminothiazol-4-yl)-3, 4-dihydro-4-phenyl pyrimidin-2(1H)-one

Authors: Lanjewar, Kushal R; Rahatgaonkar, Anjali M; Chorghade, Mukund S; Saraf, Binda D

Abstract: A series of hybrid 5-(2-aminothiazol-4-yl)-3,4-dihydro-4-phenyl pyrimidin-2(1H)-ones (ATDPP) are reported. Efficient cyclocondensation of appropriately substituted 5-(2-bromoacetyl)-3,4-dihydro-4-phenylpyrimidine-2(1H)-ones (BADPP) with thiourea in ethanol proceeds in high yield to furnish the corresponding ATDPPs. Dihydropyrimidine carboxylates (DHPMS) and their bromo derivatives are the key substrates for cyclocondensation. The ATDPPS revealed biological activity as antimicrobial and antifungal agents against S. aureus, P. aurogenosa, K. pneumonae and C. albicans.

Page(s): 1732-1737