反应详情

The green filtrate was evaporated and purified by flash chromatography on Grade v neutral Alumina, eluting first with n-hexane to remove a fast running yellow band and then with dichloromethane to obtain the major blue/gray peak containing pheophytin-a. Treatment of pheophytin-a with 500 ml sulfuric acid in methanol for 12 hours at room temperature in the dark under nitrogen, was followed by dilution with dichloromethane. The reaction mixture was rinsed with water and then 10% aqueous sodium bicarbonate and the organic layer was dried, evaporated, and the residue recrystallized from dichloromethane/methanol to obtain 1.8 gm methyl pheophorbide-a. Methyl pheophorbide-a appears to be inactive in the in vivo tumorcidal activity assay when injected at a dose of 5 mg/kg; however, it is derivatized to the active compounds of the formula (4) above (pheophorbide derivatives) wherein R3 is a hydrophobic straight or branched chain saturated or unsaturated hydrocarbyl group containing 4-25 carbons and its hydrolyzed forms of formula (5) (the chlorin derivative), wherein R3 is as thus defined.

1. customThe green filtrate was evaporated
2. custompurified by flash chromatography on Grade v neutral Alumina
3. washeluting first with n-hexane
4. customto remove
5. customwith dichloromethane to obtain the major blue/gray peak
6. washThe reaction mixture was rinsed with water
7. dry with material10% aqueous sodium bicarbonate and the organic layer was dried
8. customevaporated
9. customthe residue recrystallized from dichloromethane/methanol