Photorelease of alcohols from 2-nitrobenzyl ethers proceeds via hemiacetals and may be further retarded by buffers intercepting the primary aci-nitro intermediates.
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 intermediate formed by intramolecular trapping of the aci-tautomer, was observed and characterized.
Hellrung
Bruno
B
Departement Chemie der Universität Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
Kamdzhilov
Yavor
Y
Schwörer
Markus
M
Wirz
Jakob
J
D000080:Acetals / Q000737:chemistry; D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects*; D002021:Buffers; D004987:Ethers / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009574:Nitro Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects*; D009578:Nitrobenzenes / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects*; D010782:Photolysis
D000080:Acetals; D000438:Alcohols; D002021:Buffers; D004987:Ethers; D009574:Nitro Compounds; D009578:Nitrobenzenes