Thiochromones 4-hydroxy

Thianaphtheneqiiinone - (109) and diazomethane give a different reaction from that found with isatin, A -methylisatin and coumarandione. In as far as crystalline products could be isolated, the ring expansion occurs here between the sulfur and the carbonyl group in the 2-position. Depending on the solvent, there are formed 3-hydroxy-thiochromone (110), its 0-methyl derivative (111), or (presumably by attack on the 3-keto group of the tautomeric 3,4-diketo form of 110), 3,3 -epoxy-3-methylthiochromone (108). 

Treatment of thiochroman-4-one and some 2-substituted derivatives with [hydroxy(tosyl)iodo]benzene (HTIB) admixed with anhydrous sodium sulphate and in the absence of solvent affords the sulfoxide 325 together with some thiochromone (Equation 58) <2004ARK183>. 

Eiden, F-. and Felbcrmeir, G., 2-Aminome-thyl-3-hydroxy-1 -thiochromone Darstcllung und Reaktionen, Arch. Pharm... 316, 1034,... 

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