43049-38-3Relevant articles and documents
Multiple behaviors in the cleavage of aryl alkanoates by αand β-cyclodextrins. Processes involving two molecules of cyclodextrin
Tee, Oswald S.,Du, Xian-Xian
, p. 620 - 627 (2007/10/02)
The kinetics of ester cleavage of 4-carboxy-2- nitrophenyl alkanoates (1) (C2-C8) and of 2- carboxy-4-nitrophenyl alkanoates (2) (C2, C4,C6, C8) in an aqueous phosphate buffer (pH 11.7) containing α- orβ-cyclodextrin (α- or β-CD) show various types of behavior. Depending on the ester, its acyl chain, and the CD, the kinetics show acceleration (with or without saturation), retardation, acceleration and retardation, retardation and acceleration, or two kinds of acceleration. However, this diversity can be rationalized with simple reaction schemes. Short-chain esters mainly react conventionally through binary CD-ester complexes. For longer chains, some ester/CD combinations exhibit nonproductive 2:1 (CD:ester) binding, whereas other combinations show a cleavage process involving two CD molecules. The latter is most likely due to the attack of a CD (anion) on the 1:1 CD-ester complex or to reaction within a weak 2:1 complex. Modes of transition-state binding are probed using the pseudoequilibrium constants (KTS) introduced in earlier work (Carbohydr. Res. 1989, 192, 181).
