| abstract |
PURPOSE: To easily obtain the above-mentioned compound, effective as an anti- hypertensive agent as crystals with a high purity in a moderate condition without the need of special equipment by using a novel method with cyanophenol as the starting material. n CONSTITUTION: A compound represented by formula II is obtained by reacting 4-cyanophenol represented by formula I and isoprene in a solvent in the presence of an alkaline metal and/or a catalyst at 30 to 120°C. Then, it is converted to a compound represented by formula III in a solvent in the presence of a catalyst and/or an oxidizing agent. It is converted to 6-cyano-3,4-dihydro-2,2- dimethyl-3,4-epoxy-2H-1-benzopyran by peracid in a solvent at 0 to 20°C in the first stage. Then, the compound is reacted with 2-pyrrolidone in the presence of an alkaine metal at 20 to 100°C so as to obtain targeted (±)-6-cyano-3,4- dihydro-2,2-dimethyl-trans-4-(2-oxo-1-pyrrolidinyl)-2H-1-benzopyran-3-one. n COPYRIGHT: (C)1991,JPO |