Abstract: 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;R.sup.3 denotes a hydrogen atom or an unsubstituted or substituted alkyl group;R.sup.7 denotes hydrogen or methyl;one of R.sup.8 and R.sup.9 denotes hydrogen, hydroxy, alkoxy, alkanoyloxy, amino, substituted amino, or a group of the formula R.sup.A --SO.sub.2 --O--, in which R.sup.A denotes an organic group, and the other of R.sup.8 and R.sup.9 denotes hydrogen, orR.sup.8 and R.sup.9 together denote an oxo group, an oxime group, or a substituted oxime group.

Abstract: 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;R.sup.3 is carbamoyl or N-substituted carbamoyl;R.sup.4 is H or OH, and R.sup.5 is OH, or etherified hydroxy, or R.sup.4 +R.sup.5 is --O--CO--O-- or --O--C(R.sup.A) (R.sup.B)--O--;R.sup.6 is H, F or OH;R.sup.7 is H or CH.sub.3 ;R.sup.8 or R.sup.9 is H, OH, alkoxy, optionally substituted NH.sub.2, alkanoyloxy, or R.sup.C --SO.sub.2 O--, and R.sup.9 or R.sup.8 is H, or R.sup.8 +R.sup.9 is oxo or optionally substituted oxime;R.sup.A, R.sup.B are H or hydrocarbon; andR.sup.C is organic.

Abstract: 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):R.sup.2 SO.sub.2 SR.sub.1.sup.1 (IV)Cl--S--R.sub.1.sup.1 (V)wherein R.sub.1.sup.1 is a group R.sub.1 in which any amino substituent is protected and R.sup.2 is an alkyl group of 1-4 carbon atoms optionally substituted by a phenyl group or is a phenyl group optionally substituted by an alkyl group of 1-4 carbon atoms and thereafter if desired cleaving the ester moiety to yield the acid of the formula (II) or a salt thereof and removing the protecting group from any protected amino group present in R.