87692-16-8Relevant academic research and scientific papers
Total Synthesis of Analogues of the &β-Lactam Antibiotics. Part 1. Isoclavam-3-carboxylates
Brennan, John,Richardson, Geoffrey,Stoodley, Richard J.
, p. 649 - 655 (2007/10/02)
4-Hydroxymethylazetidin-2-one (15a), prepared from 4-vinylazetidin-2-one (16) by reductive ozonolysis, was converted into 4-iodomethylazetidin-2-one (15c) by sequential reactions involving toluene-p-sulphonyl chloride and sodium iodide.Compound (15c) reacted with methyl glyoxylate hydrate in the presence of triethylamine to give methyl hydroxy-(2-iodomethyl-4-oxoazetidin-1-yl)acetate (13b) as a 1 : 1 mixture of diastereoisomers, which was transformed into methyl 7-oxo-3-oxa-1-azabicyclo-heptane-2-carboxylate (12a), as a single exo-diastereoisomer, by the action of sodium hydride.The t-butyl, p-nitrobenzyl, and benzyl esters of 7-oxo-3-oxa-1-azabicycloheptane-2-exo-carboxylic acid,i.e. (12d-f), were similarly prepared.Brief treatment of the t-butyl ester (12d) with trifluoroacetic acid resulted in β-lactam cleavage to give (2-t-butoxycarbonyl-3-trifluoroacetyloxazolidin-4-yl)acetic acid (19c) which reacted further with trifluoroacetic acid to give (2-carboxy-3-trifluoroacetyloxazolidin-4-yl)acetic acid (19d).Hydrogenolysis of the benzyl ester (12f), in the presence of sodium hydrogen carbonate, afforded the sodium salt (12b) which underwent rapid β-lactam cleavage in aqueous solution.
