19225-87-7Relevant academic research and scientific papers
P-Hydroxyphenacyl photoremovable protecting groups Robust photochemistry despite substituent diversity
Givens, Richard S.,Stensrud, Kenneth,Conrad, Peter G.,Yousef, Abraham L.,Perera, Chamani,Senadheera, Sanjeewa N.,Heger, Dominik,Wirz, Jakob
, p. 364 - 384 (2011/06/22)
A broadly based investigation of the effects of a diverse array of substituents on the photochemical rearrangement of p-hydroxyphenacyl esters has demonstrated that common substituents such as F, MeO, CN, CO2R, CONH2, and CH3 have little effect on the rate and quantum efficiencies for the photo-Favorskii rearrangement and the release of the acid leaving group or on the lifetimes of the reactive triplet state. A decrease in the quantum yields across all substituents was observed for the release and rearrangement when the photolyses were carried out in buffered aqueous media at pHs that exceeded the ground-state pKa of the chromophore where the conjugate base is the predominant form. Otherwise, substituents have only a very modest effect on the photoreaction of these robust chromophores.
Mechanism and Mechanism-Based Inactivation of 4-Hydroxyphenylpyruvate Dioxygenase
Forbes, Brian J.R.,Hamilton, Gordon A.
, p. 343 - 361 (2007/10/02)
Six substrate analogs of 4-hydroxyphenylpyruvate, specifically pentafluorophenylpyruvate, 4-hydroxytetrafluorophenylpyruvate, 2-thienylpyruvate, 3-thienylpyruvate, thiophenol oxalate, and p-thiocresol oxalate were synthesized and their interactions with porcine liver 4-hydroxyphenylpyruvate dioxygenase investigated.Both pentafluorophenylpyruvate and thiophenol oxalate are competitive inhibitors of the enzyme with K1 values of 14 and 150 μM, respectively, but p-thiocresol oxalate has no effect on the enzymic activity.The other three substrate analogs are both substrates and mechanism-based inactivators of the enzyme with the following kinetic characteristics (compound, Km, Vmax,kinact, K', partition ratio) at pH 6.0, 37 deg C, and an air atmosphere: 4-hydroxytetrafluorophenylpyruvate, 50 μM, 1.9 mkat/kg, 1.5/min, 70 μM, 4.2; 2-thienylpyruvate, 500μM, 7.8 mkat/kg, 0.6/min, 400 μM, 41; 3-thienylpyruvate, 250 μM, 2.9 mkat/kg, 0.6/min, 300 μM, 22.When inactivated, the dioxygenase was found to contain per mole of active enzyme, 0.78 mol of label from 3-thienyl-3pyruvate and 0.85 mol of label from 4-hydroxytetrafluorophenyl-3pyruvate.The product formed from the enzyme-catalyzed oxidation of 3-thienylpyruvate was determined to be 3-carboxymethyl-3-thiolene-2-one.The implication of these results to the mechanism of the dioxygenase is considered.
