Tryptophan to Hexahydropyrroloindole

The isolation of the hexahydropyrroloindole derivative (46) on photooxidation of tryptophan irradiated in water in the presence of methylene 

Nakagawa et al. (275) believe that when photosensitized oxidations of tryptophan are carried out in solvents such as formic acid, acetic acid and water, participation of the ethylamino side chain is unfavorable and that the reaction consequently proceeds via the alternative path A of pyrrole ring cleavage. However, Savige (339) recently found that photooxidation of tryptophan in water, in the presence of methylene blue 

Photooxidation of the tryptamine derivative (73) in the presence of pyridine N-oxide in methylene chloride solution using 2537A light affords the analogous hexahydropyrroloindole (75), the epoxide (74) being the proposed intermediate 274, 275), 

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