Pteridines, LXXXVIII. Oxidations and Reactions of 2- and 4-Thiolumazine Derivatives. Synthesis and Properties of Pteridine-Sulfinates and -sulfonates

Abstract

Selective oxidations of 2-thiolumazines (10-12) by H20 2 and KMn04 respectively in basic medium led to the corresponding stable pteridin-4-one-2-sulfinates (13-15) and -sulfonates (16-18), which can be isolated in the form of their potassium salts. On oxidation of 6,7-diphenyl-2-thiolumazine (12) with 1 equivalent of H20 2 resulted the 6,7-diphenyl-pteridin-4-one-2-sulfenate (22), which is regarded as an intermediate in the formation of the sulfinates. Characterization was done by elemental analysis, pKa determination, and UV-, IR- and IH-NMR-spectra.