摘要:
A compound of the formula: ##STR1## wherein R.sup.1 is lower alkyl, andR.sup.2 is hydrogen lower alkyl, carboxy(lower)alkyl, lower alkoxy(lower)alkyl, aliphatic acyl (lower)alkyl, aromatic acyl(lower)alkyl or heterocyclic acyl(lower)alkyl,and pharmaceutically acceptable salts thereof are useful for treatment of hypertension, heart disease and thrombosis.