Synthesis of 3,4-dihydro-2H-benzopyrans from phenols and alpha,beta-unsaturated carbonyl compounds

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 alpha,beta -unsaturated aldehydes afforded benzopyrans...

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Bibliographic Details
Published inHeterocycles Vol. 55; no. 11; pp. 2051 - 2054
Main Authors Saimoto, H, Ogo, Y, Komoto, M, Morimoto, M, Shigemasa, Y
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier 01.11.2001
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
calcium chloride
1,4-addition
AQUEOUS-MEDIA
resorcinol
aqueous media
ALDOL-TYPE REACTION
WATER
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Summary: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 alpha,beta -unsaturated aldehydes afforded benzopyrans (4) or (5) in a one-pot reaction. This method was successfully applied to the synthesis of beta -tubaic acid (6), an antimicrobial 2H-1-benzopyran-6-carboxylic acid.
ISSN:0385-5414
DOI:10.3987/com-01-9333