FIELD: antibiotics. SUBSTANCE: products: ureido-derivatives of penicillin and cephalosporin of the general formula 
where R1 - H or OH; R2 - H or lower alkyl; n = 1 or 2; X - -C(CH3)2- or 
. 6-Aminopenicillin or 7-aminocephalosporin were acylated with derivative of α--aminophenylacetic acid or α--amino-p-hydroxyphenylacetic acid in the medium of solvent by acylation at pH = 1.5-3.2 with compound of the general formula 
. The yield of the end product is increased from 70% to 90%. EFFECT: increased yield of product.
