Imperial Chemical Industries Limited

Ici Pharma

Frank Loftus

Frederic H Jung

Annie A Olivier

The invention relates to a process for the manufacture of a cephalosporin derivative of the formula I: ##STR1## in which X is a sulphur or oxygen atom or a sulphinyl radical, R.sup.1 is any one of the C-3 substituents from antibacterially-active cephalosporins known in the art, R.sup.2 is a hydrogen atom or a 1-6C alkyl or 2-6C alkenyl radical, R.sup.3 is a hydrogen atom or one of a variety of radicals defined in the specification, and the pharmaceutically-acceptable acid- and base-addition salts thereof, characterized by reaction of a compound of the formula IX: ##STR2## in which R.sup.16 and R.sup.17 individually have one of the values given above for R.sup.2 and R.sup.3, or a derivative thereof in which the carbonyl group is masked, with a compound of the formula X: ##STR3## in which R.sup.18 is a hydrogen atom or any one of the cephalosporin 3-carboxylic acid protecting groups known in the art; whereafter, when R.sup.18 is other than a hydrogen atom, the protecting group R.sup.18 is replaced by hydrogen by conventional means.

Substituted cyanamide compounds useful for the manufacture of

A process for the manufacture of a cephalosporin derivative of the formula I ##STR1## in which X is sulphur, oxygen or sulphinyl; R.sup.1 is any one of the C-3 substituents from antibacterially-active cephalosporins known in the art; R.sup.2 is hydrogen or 1-6C alkyl; R.sup.3 is hydrogen or 1-6C alkyl; and the pharmaceutically-acceptable acid-addition and base-addition salts thereof, characterized by cyclization of a compound of the formula II: ##STR2## or a derivative thereof in which the carbonyl group is masked, or an acid-addition salt thereof, in which R.sup.4 and R.sup.5 individually have one of the values for R.sup.2 and R.sup.3, R.sup.6 is a nitrogen-protecting group and R.sup.7 is hydrogen or any one of the cephalosporin 3-carboxylic acid protecting groups known in the art; whereafter when the product from the cyclization retains the protecting group R.sup.7 (when R.sup.7 is other than hydrogen) the protecting group R.sup.7 is replaced by hydrogen by conventional means; and whereafter when the compound of the formula I is obtained in the form of the free base or salt, and a pharmaceutically-acceptable salt or free base respectively is required, any necessary conversion between free base and salt is carried out by conventional means.

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Macclesfield, United Kingdom

Frank Loftus