N-Demethylation of nocathiacin I via photo-oxidation

In order to improve aqueous solubility of nocathiacin I (1), a potent antibacterial agent, N-demethylation of the amino-sugar moiety was sought. Irradiation of 1 in DMF/CH2Cl2 with UV light of 380 nm led to a cyclic product 2, which was hydrolyzed to yield the desired nocathiacin VI (3). Treatment of 1 with shorter UV light caused trans–cis isomerization of a c–c double bond.