Glaxo Laboratories Limited

Peter George Sammes

Derek H Barton

Brian Edgar Looker

William George Underwood

Graham Hewitt

Ian Harold Coates

Novel semisynthetic 4-thio-azetidin-2-one derivatives of use in the production of cephalosporins, penicillins and related .beta.-lactam antibiotic compounds are provided by cleavage reactions involving the corresponding 4-dithio-azetidin-2-one derivative or a suitable thiazoline derivative, which starting materials may be obtained from penicillins without changing the configuration of the .beta.-lactam structure desired in the final product.

Alkylative cleavage of azetidinone disulfides

Novel azetidin-2-ones having in the 4-position an S-attached saturated or unsaturated, substituted or unsubstituted aliphatic group having at least 2 carbon atoms and in the 3-position an amino or blocked amino group are provided. The novel compounds are useful as intermediates in the production of cephalosporins, penicillins and related .beta.-lactam antibiotic compounds. The novel compounds are prepared by cleaving a penicillin-1-oxide in the presence of a compound containing a nucleophilic carbon-carbon multiple bond not forming part of a ring.

Azetitin-2-ores and process for preparing same

The invention relates to a novel process for the preparation of 3-hydroxy penam-1-oxides and esterified and etherified derivatives thereof. The process involves reaction of a penam-1-oxide mixed anhydride with a peracid followed by rearrangement and decarboxylation of the product initially formed to yield a 3-aroyloxy-penam-1-oxide. The latter compound may if desired subsequently be subjected to reductive cleavage to yield a 3-hydroxy compound, such reductive cleavage conveniently being effected by means of zinc and an ammonium salt under neutral or acidic conditions. The compounds prepared by the process of this invention are useful as intermediates in the preparation of antibiotics.

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Peter George Sammes