Abstract: Amino acid derivatives having both enkephalinase and ACE inhibiting properties corresponding to the formula: ##STR1##

Abstract: Amino acid derivatives of formula (Ia) and (Ib) and prodrugs thereof containing a group responsible for chelating the zinc atom of enkephalinase and angiotensin convertase enzymes are disclosed as inhibitors of these enzymes.

Abstract: Compounds corresponding to the formula (I) ##STR1## in which X represents dibromomethyl, formyl, (C.sub.1-4)alkyl, or a group CH(OR.sub.5).sub.2 or CH(OH)OR.sub.5, wherein the or each R.sub.5 is hydrogen (C.sub.1-3)alkyl or the two R.sub.5 's in the case of CH(OR.sub.5).sub.2 are linked to provide a 1,3-dioxolane or 1,3-dioxane ring, and Y represents hydrogen, 1,1-dimethylethyl, triphenylmethyl, trimethylstannyl, tributylstannyl, (1,1-dimethylethyl)dimethylsilyl, (1,1-dimethylethyl)diphenylsilyl, 2-cyanoethyl, or a group CH.sub.2 OR.sub.6 wherein R.sub.6 is methyl, phenylmethyl, 1,1-dimethylethyl, 2,2,2-trichloroethyl, benzyloxycarbonyl or 2,2,2-trichloroethyloxycarbonyl, Y being in position 1 or 2 on the tetrazole ring. The compounds of formula (I) are useful as intermediates in the synthesis of compounds possessing therapeutic activity.