2-Penem-3-carboxylic acid compounds of the formula ##STR1## in which R.sub.1 represents hydrogen, an organic radical bonded by a carbon atom to the ring carbon atom or an etherified mercapto group and R.sub.2 represents hydroxy or a radical R.sub.2.sup.A forming together with the carbonyl grouping --C(.dbd.O)-- a protected carboxyl group, 1-oxides thereof, as well as salts of such compounds having salt-forming groups, in racemic and optically active form, processes for their preparation, pharmaceutical compositions containing such compounds, and their use as antibiotics, and intermediates and their processes which are useful in the production of the compounds of the formula I.
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