New photolabile protecting groups have been found in the 2-(2-nitrophenyl)ethoxycarbonyl and the 2-(2-nitrophenyl)ethylsulfonyl group, respectively. The influence of substituents at the phenyl ring as well as the side-chain has been investigated regarding the photolysis rates on irradiation at 365 mn. beta-Branching in the side-chain leads to highly increased rates of photodeprotection. A new type of photocleavage mechanism consisting of a photoinduced beta-elimination process is proposed.
SCHIRMEISTER, H.;PFLEIDERER, W., NUCLEOSIDES AND NUCLEOTIDES, 6,(1987) N 1-2, 501-503