Improved procedure for the preparation of 3, 4??dihydro??2, 2??dimethyl??2H??1??benzopyran??3??ones

F Camps, O Colomina, A Conchillo…

文献索引：Camps, F.; Colomina, O.; Conchillo, A.; Messeguer, A. Journal of Heterocyclic Chemistry, 1985 , vol. 22, p. 1421 - 1423

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被引用次数: 4

摘要

Abstract Treatment of 2, 2-dimethyl-2H-1-benzopyrans 5 with a m-chloroperoxybenzoic acid- trifluoroacetic acid mixture and subsequent short path bulb to bulb vacuum distillation of the crude 3, 4-hydroxyesters 6 formed afforded title compounds in good yields. Suppression of trifluoroacetic acid was required when using 2, 2-di-methyl-2H-1-benzopyrans with electron donating substituents such as precocenes, as starting compounds.