Photoisomerization of 4-hydroxypyrylium cations in concentrated sulfuric acid

…, DR Bolin, KC Bradford, EL Clennan

Index: Pavlik, James W.; Patten, Arthur D.; Bolin, David R.; Bradford, Kenneth C.; Clennan, Edward L. Journal of Organic Chemistry, 1984 , vol. 49, # 23 p. 4523 - 4531

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Citation Number: 12

Abstract

2 3 whereas continued irradiation with light of 254 nm resulted in essentially complete conversion of 2H+ to 3H+, the former cation can be regenerated by irradiation of 3H+ with light of 300 nm. Accordingly, neutralization of the acid solution of 1H+ that had been irradiated at 254 nm led to the isolation of 4, 5-dimethyl-2-pyrone (2) and 5, 6-dimethyl-2- pyrone (3) in a ratio dependent on the irradiation time.