Amino acid derivatives represented by formula ##STR1## wherein His represents an L-histidyl group, X represents a straight or branched alkoxy group having 1 to 7 carbon atoms, a straight or branched alkylamino group having 1 to 7 carbon atoms, a cycloalkyloxy group having 3 to 7 carbon atoms, a morpholino group, said alkoxy group having one or more halogen atoms as substituents; or a pharmaceutically acceptable salt, are useful in the treatment of hypertension.
Novel amino acid derivatives useful as a therapeutic agent are disclosed. These amino acid derivatives and the pharmaceutically acceptable salts thereof have a human renin inhibitory effect when administered orally and are useful for treatment of hypertension, especially renin-associated hypertension.
(2R,3S)-3-amino-4-cyclohexyl-2-hydroxybutyric acid, named cyclohexylnorstatine (2a). The optically pure cyclohexylnorstatine was efficiently prepared from Boc-L-cyclohexylalaninol (3), and the stereochemistry of 1a was established by X-ray crystal analysis. The analyses of interaction between 1a and human renin using modeling techniques indicated that (1) the cyclohexyl group of P1 and the naphthyl
Cyclohexylnorstatine [(2R, 3S)-3-amino-4-cyclohexyl-2-hydroxybutyric acid] (1) and allocyclohexylnorstatine [(2S, 3S)-3-amino-4-cyclohexyl-2-hydroxybutyric acid] (2), designed as key amino acids in renin inhibitors, were synthesized diastereoselectively and simply from Boc-L-phenylalaninol.