Abstract: The invention relates to aminothiazolacetamido-3-cephem-4-carboxylic acid compounds of the formula ##STR1## in which the index n represents an integer of 1 to 4,X represents oxygen, sulphur, an --NH-- group or the direct bond,Y represents oxygen or sulphur,A represents methylene or methylene substituted by amino, hydroxy, carboxyl, sulpho, oxo, or the group .dbd.N--O--R.sup.o in which R.sup.o represents hydrogen or optionally substituted lower alkyl,R.sub.1 represents hydrogen, lower alkyl, an esterified or etherified hydroxy or mercapto group, halogen, formyl or a group of the formula --CH.sub.2 --R.sub.2 in which R.sub.2 represents an esterified or etherified hydroxy or mercapto group or a quaternary ammonium group, andR.sub.3 represents hydrogen or methoxy,in which functional groups are optionally present in protected form,salts of such compounds with acidic and/or basic groups, processes for the manufacture of these compounds, pharmaceutical agents containing such substances and their therapeutic use.

Abstract: The invention relates to 7.beta.-[D-2-amino-2-(lower alkylsulphonylamino-phenyl)-acetylamino]-3-R-cephem-4-carboxylic acid, in which R denotes lower alkoxy or halogen with an atomic number of up to 35, and their salts, which compounds possess antibiotic properties.