Bruno Hellrung, Yavor Kamdzhilov, Markus Schwörer, and Jakob Wirz, "Photorelease of Alcohols from 2-Nitrobenzyl Ethers Proceeds via Hemiacetals and May Be Further Retarded by Buffers Intercepting the Primary aci-Nitro Intermediates", J. Am. Chem. Soc. 2005, 127, 8934-8935.


Abstract: The mechanism for the photoinduced release of glycolic acid from its 2-nitrobenzyl ether was reinvestigated. The pH-dependent rate constants of the thermal reactions initiated by irradiation are similar to those reported previously for 2-nitrobenzyl methyl ether. A hemiacetal intermediate that limits the release rate of glycolic acid at pH-values < 7 was identified by time-resolved IR and UV measurements. Furthermore, 2-(2'-nitrosophenyl)-1,3-dioxolan-4-one, a long-lived inter-mediate formed by intramolecular trapping of the aci-tautomer, was observed and characterized.