Autocatalytic condensation of 1,2-orthoesters of sugars with 2,3-dihydroxy-1,4-naphthoquinone (isonaphthazarin)

The autocatalytic glycosylation of isonaphthazarine and its derivatives with 1,2-orthoesters of D-glucose and maltose in chlorobenzene has been studied. It has been established that the ratio of mono- and bisglycoside forms depends on the acidity of the glycosylated hydroxy group and its steric accessibility. Free monoglycosides of 2,3-dihydroxy-1,4-naphthoquinone have been synthesized by deacetylation with sodium methoxide in methanol.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 477–482, July–August, 1989.