ES413094A1 - Procedure for the obtaining of new derivatives of the penam-3-carboxylic acid and cefem-4-carboxylic acid. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Procedure for obtaining new derivatives of penam-3-carboxylic and cephem-4-carboxylic acid, of formula I: **(See formula)** where the grouping -S-A- means a residue of formula Ia or Ib **(See formula)** where R3 signifies a carboxylic group, optionally protected, and R4 signifies hydrogen or a methyl group, optionally substituted, and where, when residues R1 and R2 are separated, R1 signifies hydrogen and R2 signifies phenyl, thienyl or furyl, optionally substituted, and when the residues R1 and R2 are united these together with the carbon atom form a cycloalkyl ring, optionally substituted, with 4 to 7 carbon atoms, and where B represents a residue of general formula Io **(See formula)** where n = 0 or 1 and X means sulfur, when n = 0, o means carbonyloxy or sulfonyl, when n = 1, and where R6 means an organic residue and R5 represents hydrogen or an organic residue, or esters and salts of these compounds, characterized in that a compound of formula II **(See formula)** where Z means the rest **(See formula)** where R1 R2 and A have the meaning indicated under formula I, it is reacted with an acyl isocyanate of formula III 0 = C = N = -CO - B III in which B has the meaning indicated under formula I. (Machine-translation by Google Translate, not legally binding)