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Communication | Regular issue | Vol 3, No. 7, 1975, pp.521-527
Published online, 1st January, 1970
DOI: 10.3987/R-1975-07-0521
A Simple Synthesis of Benzopyrans

Tetsuji Kametani,* Kazuo Kigasawa, Mineharu Hiiragi, Haruhide Ishimaru, and Nagatoshi Wagatsuma

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan


trans-2-(3-Hydroxyphenyl)cyclohexanol (4) was converted into 1,2,3,4,4a,10b-hexahydro-6-spirocyclohexano-6H-dibenzo[b,d]pyran-9-ol (8) either by phenolic cyclisation or by acid catalysis. The corresponding 6-methyl-6-phenylbenzopyran derivative (9) was also obtained from 4 by the same methods. This type of reaction was applied to the fecile synthesis of 3,4-dihydro-6-methoxy-1-methoxycarbonyl-1-methyl-1H-2-benzopyran (11) and the hexahydro-6H-dibenzo[b,d]pyrans (18, 19, 22, and 23).