| 摘要 |
Title compds. (I; X = O, S; n = 1,2; R = H, C1-4 alkyl, substituted benzyl; R1,R2,R3 = H, Cl, Br, F, C1-3 alkyl, substituted phenyl) for treatment of chronic complication from diabetes mellitus, were prepd. by condensation of II(R4=C1-4 alkyl, substituted benzyl) and III(W1,W2 = C1, C1-4 alkoxy, imidazolyl). Thus, 6-chloro-4H-2,3-dihydrobenzopyran-4-on reacted with trimethylsilylcyanide and ZnI in ether to give 6-chloro-4-cyano-4-trimethylsilyloxy-4H-2,3-dihydrobenzopyrane.
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