Compounds are described of the formula <CHEM> wherein R1 and R4 independently represent a C1-4 alkyl group; R2 and R3 independently represent a C1-6 straight or branched alkyl chain or alkoxy group; R5 represents a straight or branched chain C1-13 alkyl group or a C5-8 cycloalkyl group which may be substituted by a C1-3 alkyl substituent; R6 represents a halogen atom or a straight or branched C1-3 alkyl group. R7 represents a C1-4 alkyl group [optionally substituted by hydroxy, C1-3 alkoxy or trifluoromethyl or by a group NR8R9 where NR8R9 forms a saturated 5 to 7 membered ring optionally containing an additional heleroatom which is oxygen]; or R7 represents a phenyl C1-2 alkyl group in which the phenyl portion is optionally substituted by 1 to 3 C1-3 alkyl or C1-3 alkoxy groups or halogen atoms. The compounds represented by formula (I) reduce intracellular calcium ion concentration by limiting transmembranal calcium ion influx and thus may be useful for the treatment of cardiovascular disorders such as hypertension.
