Flash photolytic release of alcohols from photolabile carbamates or carbonates is rate-limited by decarboxylation of the photoproduct.
Flash photolysis of a 7-nitroindolinyl carbamate derivative in neutral aqueous solution rapidly generated a monoalkyl carbonate salt. The rate constant for subsequent decarboxylation of this salt [mono(2-phosphoryloxyethyl) carbonate], determined by rapid scan IR difference spectroscopy, was 0.4 s(-1) at pH 7.0, 20 degrees C. This rate reflects release of the product alcohol upon photolysis of the parent compound. In general, alcohols protected as photolabile carbamate (or carbonate) derivatives will therefore be released too slowly for studies of the kinetics of millisecond time scale biological processes.
Papageorgiou
George
G
National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK NW7 1AA.
Barth
Andreas
A
Corrie
John E T
JE
D000438:Alcohols / Q000737:chemistry*; D002219:Carbamates / Q000737:chemistry* / Q000528:radiation effects; D002245:Carbon Dioxide / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry* / Q000528:radiation effects; D003653:Decarboxylation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010782:Photolysis; D017550:Spectroscopy, Fourier Transform Infrared
D000438:Alcohols; D002219:Carbamates; D002254:Carbonates; D002245:Carbon Dioxide