Beecham Group Plc

Edward G Brain

Neal Frederick Osborne

Eric Hunt

Andrew K Forrest

Antibacterially active 11,12-carbonate derivatives of erythromycin 9-(optionally substituted)oxime and 9-imino compounds and their pharmaceutically acceptable ester or acid addition salt thereof: ##STR1## wherein R.sup.1 denotes an oxime group, a substituted oxime group, or an imino group;

Erythromycin a 11,12-carbonate 9-oxime derivatives

Antibacterially active 6-carbamate erythromycin derivatives of formula I and their pharmaceutically acceptable esters and acid addition salts; ##STR1## wherein: R.sup.1 or R.sup.2 is optionally substituted amino, or R.sup.1 or R.sup.2 +R.sup.5 is --O--C(R.sup.A)(R.sup.B)--O--, and R.sup.2 or R.sup.1 is H, or R.sup.1 +R.sup.2 is oxo, oxime, substituted oxime, or imino;

6-carbamade erythromycin derivatives

A process for the preparation of the compounds of the formula (II): ##STR1## and salts and cleavable esters thereof wherein R.sub.1 is a hydrocarbon group of up to 12 carbon atoms and which optionally also contain up to 4 heteratoms selected from oxygen, nitrogen, sulphur or chlorine and bromine which process comprises the reaction of a cleavable ester of a compound of the formula (III): ##STR2## with one equivalent of a strong base of low nucleophilicity and thereafter with a compound of the formula (IV) or (V):

Process for their preparation of .beta.-lactam antibacterial agents

Antimicrobially active substituted ceph-3-ems, procedure for their preparation and intermediates for use in the procedure are described. These cephalosporins are characterized by having a 2- or 3- pyridyl group attached to the carbon atom of the methylene group in the 3-position by a carbon-carbon bond and not a carbon-nitrogen bond.

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Betchworth, United Kingdom

Edward G Brain