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Communication | Regular issue | Vol 55, No. 11, 2001, pp.2051-2054
Published online, 1st January, 1970
DOI: 10.3987/COM-01-9333
■ Synthesis of 3,4-Dihydro-2H-benzopyrans from Phenols and α,β-Unsaturated Carbonyl Compounds

Hiroyuki Saimoto, Yoshie Ogo, Mie Komoto, Minoru Morimoto, and Yoshihiro Shigemasa*

*Tottori University, Faculty of Engineering, Department of Materials Science, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

The reaction between 2’,4’-dihydroxyacetophenone and methyl vinyl ketone catalyzed by CaCl2/KOH in aqueous methanol yielded a 1,4-adduct, which was cyclized to 3,4-dihydro-2H-benzopyran (4) by acidic treatment. Analogous reaction using α,β-unsaturated aldehydes afforded benzopyrans (4) or (5) in a one-pot reaction. This method was successfully applied to the synthesis of β-tubaic acid (6), an antimicrobial 2H-1-benzopyran-6-carboxylic acid.