Photochemical properties of hypocrellin A,B and their oxides

Hypocrellin A and B in methanol were autosensitized and photooxygenated to 1, 4, 6, 7 and 2, 5, 8, 9 respectively. 1 in methanol was photooxygenated to 6 and 7 under the sensitization by HB. 1 in methanol was photooxygenated to 7 under the sensitization by Rose bengal. 1 in benzene irradiated with medium-pressure-mercury lamp was photolyzed to 3 in the presence of iodine.