Theoretical study of the o-OH participation in catechol ester ammonolysis.
The possible catalytic effect of the vicinal hydroxyl group during the ammonolysis of acetylcatechol has been studied by first principle calculations. A very efficient intramolecular catalysis was found to occur when the catechol ester o-OH group is deprotonated: the activation energy of the ammonolysis decreases by 24 kcal mol(-1) as compared to that of acetylphenol ammonolysis. Using this value, the o-oxyanion-catalysed intramolecular ammonolysis was estimated to be orders of magnitude faster than the ammonolysis of acetylphenol or nonionised acetylcatechol. The analogy with the aminolysis of peptidyl-tRNA that occurs during protein biosynthesis implies several orders of magnitude acceleration due to complete or partial deprotonation of its 3'-terminal adenosine 2'-OH providing a mechanistic possibility for general acid-base catalysis by the ribosome.
Rangelov
Miroslav A
MA
Laboratory of BioCatalysis, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria.
Vayssilov
Georgi N
GN
Yomtova
Vihra M
VM
Petkov
Dimiter D
DD
D019342:Acetic Acid / Q000737:chemistry; D000641:Ammonia / Q000737:chemistry*; D000838:Anions / Q000737:chemistry; D002396:Catechols / Q000737:chemistry*; D004952:Esters; D010636:Phenols / Q000737:chemistry; D011522:Protons; D012997:Solvents / Q000737:chemistry; D013816:Thermodynamics
D000838:Anions; D002396:Catechols; D004952:Esters; D010636:Phenols; D011522:Protons; D012997:Solvents; D000641:Ammonia; D019342:Acetic Acid