Hoechst Aktiengesellschaft

Rolf Horlein

Rudolf Lattrell

Uwe Gerlach

Gerd Fischer

Norbert Krass

Elisabeth Defossa

Ulrich Stache

Theodor Wollmann

Astrid Markus

Dieter Isert

Michael Limbert

Karl-Heinz Budt

Reiner Kirrstetter

Theo Wollmann

Walter Durokheimer

The invention relates to a process which comprises a compound of the formula II ##STR1##

Process for the preparation of cephem prodrug esters

The invention relates to a process for the preparation of cephem prodrug esters of the formula: ##STR1## in which R.sup.1 is C.sub.1 -C.sub.5 -alkanoyloxy-C.sub.1 -C.sub.3 -alkyl or C.sub.1 -C.sub.5 -alkoxycarbonyloxy-C.sub.1 -C.sub.3 -alkyl and X is an inorganic or organic anion, and in which the hydroxyimino group is present in the syn-form.

Enterally absorbable diastereomers of 1-(isopropoxycarbonyloxy)ethyl (6R,7R)-7-[2-(2-aminothiazol-4-yl)-2-(Z)-(methoxyimino)acetamido]-3-(metho xymethyl)-3-cephem-4-carboxylate of the formula I ##STR1## and their physiologically acceptable salts and also diastereomerically pure salts of the compounds of the formula II ##STR2## where HX is a mono- or polybasic acid and where X is an inorganic or organic physiologically acceptable anion, and a process for the preparation of these compounds of the formula I or II, which comprises first precipitating the more sparingly soluble diastereomer of the formula IV in the mixing together of 1 equivalent of a solution of the diastereomer mixture of the formula III with 0.2-2 equivalents of a solution of the acid component HY and separating it off by filtration, then precipitating the more readily soluble diastereomer of the formula IV from the filtration solution, it being possible for the acid component HY to be identical or different in the consecutive partial steps and any desired sequence of addition of different acid components HY being possible, and optionally further purifying the obtained salts by crystallization, are described.

Diastereomers of 1-(isopropoxycarbonyloxy)ethyl 3-cephem-4-carboxylate

Tetracyclic antibiotics and processes for their preparation .beta.-Lactam antibiotics of the formula I, and their pharmaceutically tolerable salts ##STR1## where X is (CH.sub.2).sub.0-2, CR(a)R(b), O, SO.sub.0-2 or NR(c),

Tetracyclic antibiotics and processes for their preparation

Compound I ##STR1## is obtained by reaction of compound II with compound III

Process for the preparation of penem compounds

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Frankfurt am Main, Germany

Rolf Horlein