ESTERS OF PHENYLALKANOIC ACID

The esters of phenylalkanoic acid of the formula: (see fig. I) ( I ) wherein R1 is 4-10 membered, saturated or unsaturated, mono- or bi-cyclic hetero ring containing as hetero atoms: (i) one or two nitrogen, (ii) two or three of nitrogen and sulfur in total, or (iii) one or two sulfur; R2 is hydrogen; or R1 and R2, taken together with a nitrogen to which they are attached, form 4-7 membered, saturated or unsaturated, mono-cyclic hetero ring containing as hetero atoms: (i) one or two nitrogen, or (ii) two or three of nitrogen and oxygen in total, the aforementioned hetero rings, represented by R1 or formed by R1 and R2, taken together with a nitrogen to which they are attached, may be substituted by one substituent selected from C1-4 alkyl and C2-5 acyl; R3 each, independently, is hydrogen or C1-4 alkyl; R4 is hydrogen, halogen, trihalomethyl, C1-4 alkyl, C1-4 alkoxy, C2-5 acyl, cyano, nitro or nitroxy; R5 each, independently, is hydrogen, C1-4 alkyl or phenyl; or the two R5's, taken together with a carbon to which they are attached, form cyclopentane or cyclohexane; and the pharmaceutically acceptable acid addition salts thereof, have .beta.1-adrenergic receptor blocking activity, and therefore, are useful for the prevention of and/or in the treatment of cardiovascular diseases such as angina pectoris, myocardial infarction, congestive heart failure, hypertension, arrhythmia, etc.