On the alcohol- and water-catalyzed tautomerization of vitamins K1- and K2-derived quinone methide intermediates.
Rates of conversion of 1,3-quinone methides into the corresponding 1,2-quinone methide tautomers, formed upon laser-flash excitation of vitamins K(1) and K(2) in CH(3)CN solutions, were determined in the presence of hydroxylic solvents (ROH; R = H, alkyl). In all cases, the tautomerization process is accelerated in the presence of ROH, and the corresponding observed rate constants show a cubed dependence on ROH concentration. This high-order dependency is attributed to a proton-relay transfer involving 3 equiv of ROH in each case.
Swartz
Angela M
AM
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 2G1.
Barra
Mónica
M
Kuntz
Donna
D
D000438:Alcohols / Q000737:chemistry*; D002384:Catalysis; D003903:Deuterium; D045563:Indolequinones / Q000737:chemistry*; D007700:Kinetics; D007834:Lasers; D015394:Molecular Structure; D011522:Protons; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D010837:Vitamin K 1 / Q000737:chemistry*; D024482:Vitamin K 2 / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D000438:Alcohols; D045563:Indolequinones; D011522:Protons; D012997:Solvents; D014867:Water; D024482:Vitamin K 2; C068040:quinone methide; D010837:Vitamin K 1; D003903:Deuterium