1. Field of the Invention
The compounds provided by the present invention are classified into a group of calcium channel blockers (hereinafter referred to as Ca-blockers), and have potent antihypertensive and coronary vasodilating actions which last for hours. These compounds are useful in the treatment of cardiovascular diseases such as angina pectoris, hypertention, cerebrovascular dysfunction, arrhythmia or the like, and have the advantage that they have no systole inhibitory action as an advese reaction usually seen in the use of the analogous known-compounds.
2. Prior Art
Compounds having Ca-blocking, effect have commonly been used in the treatment of cardiovascular diseases such as angina pectoris, hypertention, cerebrovascular dysfunction, arrhythmia or the like, and have become well-known because of their high efficacy. In particular, a series of 1,4-dihydropyridine derivatives have been extensively researched and developed as Ca-blockers. Examples of useful Ca-blockers are Nifedipine (U.S. Pat. Nos. 3,485,847 and 3,644,627), Nisoldipine (Japanese Patent Publication No. 56-47185), 2-amino-1,4-dihydropyridine derivatives (JPN Pat. Pub. No. 57-20306), Nicardipine (JPN Unexam. Pat. Pub. No. 49-109384), and the like. Some examples of pyrazolodihydropyrindine derivatives, the production thereof and their Ca-blocking action are disclosed in JPN Unexam. Pat. Pub. No. 59-118786 and in JPN Unexam. Pat. Pub. No. 59-65089 and JPN Pat. Appln. Nos. 58-166258 and 59-53118 by the present inventors.