NISCAIR Online Periodicals Repository Collection: IJC-B Vol.44B(06) [June 2005]

Amidation of amines with esters catalyzed by Candida antarctica lipase (CAL)

Sun, 29 May 2005 22:58:59 GMT

Title: Amidation of amines with esters catalyzed by Candida antarctica lipase (CAL)

Authors: Yang, Bo; Zhang, Yanjun; Zhang, Shusheng; Izumi, T

Abstract: Candida antarctica lipase (CAL) is used to convert amines and esters into amides, especially as a chiral resoluting catalyst for the enantioselective amidation of racemic esters or racemic amines in an effort to demonstrate the ability of lipase to differentiate between enantiomeric substrates. It is a very useful synthetic method for amides. The effects of substrate modification on the yield and enantiomeric excess (ee) are studied. The R-enantiomer will react faster for racemic mixture of amine in which the amino group attaches directly to the chiral carbon, and the same for racemic mixture of ester in which the carbonyl group attaches directly to the chiral carbon. The enantioselectivity of CAL is complicated for the amidation of racemic mixture of amine with racemic mixture of ester.

Page(s): 1312-1316

Synthesis and reactions of 4-(aminoaryl)-methylene-2-aryl-2-imidazolin-5-ones

Sun, 29 May 2005 22:58:59 GMT

Title: Synthesis and reactions of 4-(aminoaryl)-methylene-2-aryl-2-imidazolin-5-ones

Authors: Shafi, P M; Sobha, T D; Basheer, P A M; Waibel, R

Abstract: Benzimidic acid methyl esters on heating with glycine ester in toluene in presence of sodium acetate yield 4-(aminoaryl)methylene-2-aryl-2-imidazolin-5-ones. They undergo acetylation and benzoylation on reaction with acetic anhydride and benzoyl chloride, respectively. The ¹³C assignment of some of the carbon atoms of one of the acetyl derivatives has been done by HMQC and HMBC experiments.

Page(s): 1298-1300

Synthesis, antimicrobial and antiinflammatory activities of 4-oxothiazolidines and their 5-arylidenes

Sun, 29 May 2005 22:58:59 GMT

Title: Synthesis, antimicrobial and antiinflammatory activities of 4-oxothiazolidines and their 5-arylidenes

Authors: Yadav, R; Srivastava, S D; Srivastava, S K

Abstract: As a part of systematic investigation of synthesis and biologically active compounds of 2-mercaptobenzothiazoles, several new 2-[(aryl)-3-(acetylamino)-1,3-thiazolidin-4-ones]-2-mercaptobenzothiazole 4 and 2-{5-arylidene-2-phenyl-3-(acetylamino)-1,3-thiazolidine 4-ones}-2-mercaptobenzothiazole 5 from 2-mercaptobenzothiazole have been synthesised and tested for their antimicrobial and antiinflammatory activities. The structures of all the synthesized compounds have been determined by spectral and chemical methods.

Page(s): 1262-1266

Bismuth oxide perchlorate catalysed efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones: An improved high yielding protocol for the Biginelli reaction

Sun, 29 May 2005 22:58:59 GMT

Title: Bismuth oxide perchlorate catalysed efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones: An improved high yielding protocol for the Biginelli reaction

Authors: Reddy, Y Thirupathi; Reddy, P Narsimha; Kumar, B Sunil; Rao, G V P; Rajitha, B

Abstract: Dihydropyrimidines are prepared by a one-pot cyclocondensation of aldehydes, β-ketoesters and urea in acetonitrile by using bismuth oxide perchlorate as the catalyst for the first time is described. Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of excellent yields (85-95%) and short reaction time (2-4 hr) at lower temperature (40-50^oC).

Page(s): 1304-1306