Regioselective Carboxylation of 9-Xanthenones with Manganese(III) Acetate
作者:Hiroshi Nishino、Kazu Kurosawa
DOI:10.1246/bcsj.56.474
日期:1983.2
Seven 9-xanthenones were oxidized with manganese(III) acetate to give carboxy-, dicarboxy-, (acetoxymethyl)(carboxy)-, (carboxy)(hydroxymethyl)-, and acetoxymethyl-9-xanthenones, and to yield small amounts of (carboxymethyl)(carboxy)-, carboxymethyl-, (acetoxymethyl)(carboxymethyl)-, bis(acetoxymethyl)-, and diacetoxymethyl-9-xanthenones. The carboxyl group was preferentially introduced into the peri positions and the acetoxymethyl groups were located at positions ortho to the methoxyl or methyl group. The regioselectivity and mechanism of the carboxylation reaction is discussed briefly.
Oxidation of 9-Xanthenones with Lead(IV) Acetate. Formation of Di-γ-lactones
作者:Hiroshi Nishino、Kazu Kurosawa
DOI:10.1246/bcsj.56.2847
日期:1983.9
The oxidation of 9-xanthenones with lead(IV) acetate afforded 3a,3b,6a,12b-tetrahydro-2H-difuro[3,2-a:3′,2′-c]xanthene-2,5,7(3H,6H)-triones in addition to other products. Characterization of the di-γ-lactones and the difference between the oxidation reaction of lead(IV) and manganese(III) acetates in the 9-xanthenone system are discussed.