PROCESS FOR PREPARING (±)-6-CYANO-3,4-DIHYDRO-2,2- DIMETHYL-TRANS-4-(2-OXO-1-PYRROLIDINYL)-2H-1-BENZOPYRAN- 3-OL Russian patent published in 1995 - IPC

FIELD: medicine. SUBSTANCE: the product is (+)- 6-cyano-3,4-dihydro-2,2-dimethyl-trans-4-(2-oxo-1- (pyrrolidinyl)-2H-1-benzopyran-3-ol of the empirical formula: C₁₆H₁₈N₂O₂, mp 229-230 C. The yield is 90 Reagent: 4-cyanophenol. Reagent 2: in the presence of an alkali metal and/or a catalyst. Reagent 3: 6-cyano-3,4-dihydro- 2,2-dimethyl-2H-1-benzopyrane which is converted to 6- cyano-2,2-dimethyl-2H-1-benzopyrane at 40-150 C in a solvent in the presence of a catalyst and/or an oxidizer or by bromination of a molecule into the benzyl moiety and dehydrobromination of the resulting 6-cyano--3,4- dihydro-2,2-dimethyl-4-bromo-2H-1-benzopyrane, 6-cyano- 3,4-dihydro-2,2-dimethyl-3,4-epoxy-2H-1-benzopyrane is obtained from 6-cyano-2,2-dimethyl-2H-1-benzopyrane in one stage by treatment with a per acid in a solvent followed by reaction of this compound with 2-pyrrolidone in the presence of an alkali metal at 20-100 C and recovery of the desired product. The process makes it possible to increase the yield of cromacalime. EFFECT: more efficient preparation process. 12 cl