ANTIBIOTIKA UND VERFAHREN ZU IHRER HERSTELLUNG

Novel 6 beta -isocyano penicillin and 7 beta -isocyano cephalosporin esters of value as intermediates in the synthesis of penicillin and cephalosporin antibiotics are provided. The novel compounds may be prepared by reaction of the corresponding 6 beta -formamido penicillin ester or 7 beta -formamido cephalosporin ester with an acid halide derived from phosphorus, sulphur or carbon or from an oxygen acid of one of said elements, suitable halides including thionyl chloride or phosgene, or with a trivalent phosphorus compound such as triphenylphosphine and a halogenated hydrocarbon such as carbon tetrachloride. The conversion of the novel products to 6 beta - and 7 beta - ( alpha -hydroxy) arylacetamido penicillins and cephalosporins respectively by reaction under acidic conditions with an aromatic aldehyde followed by treatment with an aqueous medium is also described.