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.
A novel method for the formation of antibiotic (±)-PS-5 is described, involving intramolecular cyclization of a β-lactam with a tricarbonyl residue. This procedure represents another application of the enamine-singlet oxygen reaction in synthesis.
Olivanic acid analogues. Part 1. Total synthesis of the 7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate system and some related β-lactams
作者:John H. Bateson、Andrew J. G. Baxter、Patricia M. Roberts、Terence C. Smale、Robert South-Gate
DOI:10.1039/p19810003242
日期:——
4-Allylazetidin-2-one, prepared from penta-1,4-diene and chlorosulphonyl isocyanate, has been used to synthesise the parent 7-oxo-1-azabicyclo[3.2.0] hept-2-ene-2-carboxylate system of the naturally occurring olivanic acids, using an intramolecular Witting reaction to construct the 2,3-double bond. Cyclisation of ketones derived from the 4-allyl grouping produced 3-substituted derivatives, while use
corresponding ϵ-lactam was also formed in 38 % yield. When N-(2-fluoroallyl) derivatives were used instead of fluoroacryloyl derivatives, six-, seven-, and eight-membered N-heterocycles were obtained in low yields. This method was also used to synthesize fluorinated α,β-unsaturated analogues of pyrrolizidine and indolizidine alkaloids from prolinol, and also to synthesize N-benzyl-3-fluoroquinolone in