Synthesis of pyrrolidine-3-carboxylic acid derivatives <i>via</i> asymmetric Michael addition reactions of carboxylate-substituted enones
作者:Feng Yin、Ainash Garifullina、Fujie Tanaka
DOI:10.1039/c7ob01484h
日期:——
concisely synthesize highly enantiomerically enriched 5-alkylsubstituted pyrrolidine-3-carboxylic acids, organocatalytic enantioselective Michael addition reactions of 4-alkyl-substituted 4-oxo-2-enoates with nitroalkanes have been developed. Using the developed reaction method, 5-methylpyrrolidine-3-carboxylic acid with 97% ee was obtained in two steps.
Cephalosporin analogues and processes for the preparation thereof
申请人:——
公开号:US04264597A1
公开(公告)日:1981-04-28
Compounds of the formula ##STR1## wherein X is --O--or --S--; R.sup.1 is amino or a substituted amino group; R.sup.2 is carboxy or a protected carboxy group; and the heavy solid line means single or double bond; the compounds are useful in the treatment of infectious diseases particularly fungal infection, in human beings and animals.
Compounds are described of the formula (II): ##STR1## wherein R.sub.1 is a group such that CO.sub.2 R.sub.1 is an ester group; A.sub.1 is a hydrogen atom; and A.sub.2 is a group CR.sub.2 R.sub.3 R.sub.4 wherein R.sub.2 is a hydrogen atom or a hydroxyl group; R.sub.3 is a hydrogen atom or a lower alkyl group; and R.sub.4 is a hydrogen atom or a lower alkyl group, a benzyl group, a phenyl group or is joined to R.sub.3 to form part of a C.sub.5-7 carboxylic ring or is a group of the formula CH(OH)R.sub.5 or CHX wherein R.sub.5 is a hydrogen atom or lower alkyl group and X is an oxygen atom or a CR.sub.6 R.sub.7 group where R.sub.6 is a hydrogen atom or a lower alkyl, phenyl, CN, CO.sub.2 R.sub.8 where R.sub.8 is a lower alkyl, phenyl or benzyl group and R.sub.7 is a hydrogen atom or a lower alkyl group or is joined to R.sub.6 to form part of a C.sub.5-7 carbocyclic ring. These compounds have been found to possess antibacterial properties. The preparation of these compounds is described.
4-Allyl azetidinone intermediate for .beta.-lactam antibacterial agents
申请人:Beecham Group Limited
公开号:US04401595A1
公开(公告)日:1983-08-30
Compounds are provided of the formula (II): ##STR1## wherein R.sub.1 is a group such that CO.sub.2 R.sub.1 is an ester group and A.sub.1 is a hydrogen atom or a methyl group. These compounds possess antibacterial activity. The preparation of these compounds is described.
The stereoselective syntheses of spirobicyclic and tetracyclic pyrazolidinones are reported based on a (3+2) annu- lation between hydrazones and α-oxoketenes. Some of these conformationally constrained molecules were resolved as enantiopure materials by HPLC techniques and evaluated as amino- catalysts for iminium activation in a model Diels–Alder cyclo- addition.