STUDIES RELATED TO THE STRUCTURES OF THE OLIVANIC ACIDS MM 13902, MM 4550 AND MM 17880. THREE β-LACTAM ANTIBIOTICS FROM STREPTOMYCES OLIVACEUS

Article abstract of DOI:10.1016/S0040-4020(01)92148-9

MM 13902, a β-lactam antibiotic isolated from Streptomyces olivaceus, has been identified as (5R,6R)-3-<(E)-2-acetamidoethenylthio>-6-<(S)-1-hydroxysulphonyloxyethyl>-7-oxo-1-azabicyclo<3.2.0>hept-2-ene-2-carboxylic acid (2) by chemical and spectroscopic studies.The related olivanic acids MM 4550 and MM 17880 have been shown to be the corresponding 3-<(E)-2-acetamidoethenylsulphinyl>- and 3-(2-acetamidoethylthio)-derivatives (1 and 5), respectively.A number of carboxylate and sulphate esters of 1,2 and 5 have been prepared.A key reaction in the characterisation of 2 was the oxidative degradation of its C-2 monomethyl ester (12) in dimethylsulphoxide to methyl 3-<(E)-2-acetamidoethenylthio>-5-<(1R,2S)-1-carboxy-2-hydroxysulphonyloxyprop-1-yl>pyrrole-2-carboxylate (22).The configuration of the C-6 substituent of 2 was determined by a stereospecific elimination reaction of its ethyl sulphate, p-nitrobenzyl carboxylate (19) to yield the 6-(E)-ethylidene derivative (32).MM 13902 was oxidised to MM 4550 with m-chloroperbenzoic acid.