A Simple and Efficient Synthesis of 2-Methyl-2-trifluoromethylchroman-4-ones from 2-Trifluoromethyl-4H-chromen-4-imines and Malonic Acid

Abstract

N-Benzyl-2-trifluoromethyl-4H-chromen-4-imines and malonic acid on heating in anhydrous dioxane afford 2-trifluoromethyl-2-methylchroman-4-ones in ∼60% yield. 2-Methyl-2-tri­fluoromethyl-4-oxochromane-6-carbaldehyde and 2-methyl-2-trifluoromethyl-4-oxochromane-6-carboxylic acid, the fluorinated analogues of natural lactarochromal and the corresponding acid, were obtained by the oxidation of 2,6-dimethyl-2-trifluoromethylchroman-4-one with K₂S₂O₈.

Key words

N-benzyl-2-trifluoromethyl-4H-chromen-4-imines - malonic acid - 2-methyl-2-trifluoromethylchroman-4-ones - oxidation - fluorinated analogues of natural compounds

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Sosnovskikh, V. Ya.; Usachev, B. I. Tetrahedron 2002, in press.