Coumarandiones

The same insertion of a methylene group between a benzene ring and carbonyl group is also found in the reaction of coumarandione (105 106 107). (The reaction course described by Schonbcrg et could not be confirmed. )... 

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). 

The difference in the reaction course for thianaphthenequinone can be explained in the following way in isatin and coumarandione the carbonyl group in the 3-position is considerably more reactive than... 

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