To obtain the subject new compound useful as an agent for preventing and treating diabetic complications and as an aldose reductase inhibitor.
A compound of formula I [R1 and R2 are each hydroxy, a (aryl-substituted) lower alkoxy or a halogen, wherein one of R1 and R2 is the halogen, and the other is hydroxy; one of R3 and R4 is H, and the other is hydroxymethyl, a lower alkylaminomethyl, formly or the like, or R3 and R4 together form 0 or are connected to each other to form a tetrahydrofuran ring, a pyrrolidine ring or the like], e.g. 2,8-dimethoxy-5H-dibenzo[a,b]cyclohepten-5- one of formula II. The compound for formula I is produced e.g. by a method comprising catalystically reducing a compound of formula IV (R2 is R1) obtained from a compound of formula III (R1 is a lower alkyl or a halogen) as a starting raw material, closing the ring of the compound of formula IV in the presence of polyphosphoric acid, brominating the closed compound, dehydrobrominating the brominated product to obtain a compound of formula V, and further performing other processes.
SAI OUSHIYOU
