Production of 1,4-dihydropyridine derivatives

PURPOSE: To obtain a high yield of the title compds. of high purities, which compds. are useful for the treatment of hypertension, without forming by- products and without necessitating the recrystallization and purification in a short time by reacting a specified new compd. with methyl acetoacetate and an amino compd. in an inert solvent. CONSTITUTION: A new compd. of formula I (wherein n is 1 or 3; and R is a group of formula II or the like when n is 1, and R is H when n is 3) is reacted with methyl acetoacetate of formula III and, if necessary, an amino compd. of formula IV (wherein Z is a group of formula V when k is 1 and p is 0, or a 1-5C alkanoyloxy when both k and p are 1; and when k is 0, one of p's is 0 and the other is 1) in an inert solvent, or 2-nitrobenzaldehyde is reacted with the compd. of formula III and an aqueous ammonium hydroxide soln. in an inert solvent at a temp. of 101 to 120°C under a pressure of 2.0 to 6.0 bar in one step to obtain nifedipine of formula VI. COPYRIGHT: (C)1989,JPO