The reaction of 4H-1-benzopyran-4-one (chromone, bar1,) and its substituted derivatives with hydroxylamine in aqueous alcohols gives isoxazoles 5 and 10, as the major products, whereas 1a is transformed mainly into 8a with hydroxylamine hydrochloride in anhydrous methanol, compounds 5a, 9a and 10a can be also isolated, and the formation of 6a and 7a has been detected, as well. Depending on the character of the substituent, substituted ...
