Derivatives of aspartic acid, preparation and use thereof

N-(Amidino- or guanidino-substd. acyl)- aspartic acid derivs. of formula HN=C(CH2)-X-NH-CH(COR)CH2CHOOH(I) (I) and their salts are new: In (I), X = amino-substd. glycyl, benzoyl or phenoxyacetyl deriv. gp. of formula (i)-(iv); A = (CH2)m, O or direct bond; n = 1-4; k = 0-7; m = 0-4; R = -OR2R3 or -NH-R4; R1 = H; 1-28C alkyl, 3-28C cyclo-alkyl or phenyl (all opt. substd. by one or more of OH, COOH, 1-4C alkoxycarbonyl, arylmetho-cycarbonyl, carboxamido, 1-4C alkylaminocarbonyl, NH2, SH, 1-4C alkoxy, 3-8C cycloalkyl, imidazolyl, indolyl, pyrrolidinyl, hydroxypyrrolidinyl, halogen and phenyl or phenoxy (themselves both opt. substd. by one or more of OH, 1-4C alkyl, halogen, NO2 and CF3)); 3-81C alkyl interrupted by one or more O; or (3-81C alkoxy)-carbonyl interrupted by one or more O; R2,R3 = H, or as R1; or R2 = H and R3 = triglyceride deriv. gp. of formula (v) or (vi); or NR2R3 - 5- or 6-membered satd. heterocycle opt. also contg. O or NR5; R4 = residue of an aminoacid or dipeptide, in which the peptide bond may be reduced to NHCH2; R5 = H, 1-4C alkyl, phenyl, (1-4C alkyl)-phenyl or (1-4C alkoxy)-phenyl; R6 = H, 1-4C alkyl, phenyl or phenyl (1-4C) alkyl; P,Q = 1-20.