Imperial Chemical Industries Limited

Ici Pharma

Georges Pasquet

Jean J Lohmann

Robert Hugh Bradbury

Frederic H Jung

Peter R Marsham

Jean C Arnould

John Peter Bailey

A cephalosporin derivative of the formula I: ##STR1## in which X is S, O, CH.sub.2 or SO, ##STR2## represents one of C-7 acyl groups known in the cephalosporin art, R3 is hydrogen or methoxy, R4 is hydrogen, optionally substituted alkyl or allyl, and R5 is an aromatic heterocyclic ring system which is linked via carbon, and which contains a quaternized nitrogen atom.

Cephalosporin intermediates

Cephalosporin derivatives of the formulae ##STR1## wherein X is sulphur, oxygen, methylene or sulphinyl, R3 is hydrogen or methoxy, R54 is hydrogen or a carboxyl protecting group, R.sup.51 is a (1-4C)alkyl group, R.sup.4 is hydrogen, (1-4C)alkyl, halo(1-4C)alkyl, hydroxy(1-4C)alkyl, (1-4C)alkoxy(1-4C)alkyl, carboxy (1-4C)alkyl, amino (1-4C)alkyl, cyano(1-4C)alkyl, (1-4C)alkanoylamino(1-4C)alkyl, allyl, furfuryl, benzyl or pyridyl(1-4C)alkyl and R.sup.52 is an amino protecting group and salts thereof are useful as intermediates in the preparation of cephalosporin antibiotics.

Intermediates for the preparation of beta-lactam antibiotics

A cephalosporin derivative of the formula I: ##STR1## in which X is ##STR2## represents one of C-7 acyl groups known in the cephalosporin art, R3 is hydrogen or methoxy, R4 is hydrogen, optionally substituted alkyl or allyl, and R5 is an aromatic heterocyclic ring system which is linked via carbon, and which contains a quaternized nitrogen atom.

Cephalosporin derivatives

A cephalosporin derivative of the formula I: ##STR1## in which X is S, O, CH.sub.2 or SO, ##STR2## represents one of the C-7 acyl groups known in the cephalosporin art, R3 is hydrogen or methoxy, R4 is hydrogen, optionally substituted alkyl, allyl, furfuryl or benzyl, and R5 is an aromatic heterocyclic ring system which is linked via carbon, and which contains a quaternized nitrogen atom.

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Bazancourt, France

Georges Pasquet