194940-15-3Relevant articles and documents
A modification of the Hammett equation for predicting ionisation constants of p-vinyl phenols
Sipilae, Julius,Nurmi, Harri,Kaukonen, Ann Marie,Hirvonen, Jouni,Taskinen, Jyrki,Yli-Kauhaluoma, Jari
, p. 417 - 425 (2005)
Currently there are several compounds used as drugs or studied as new chemical entities, which have an electron withdrawing group connected to a vinylic double bond in a phenolic or catecholic core structure. These compounds share a common feature - current computational methods utilizing the Hammett type equation for the prediction of ionisation constants fail to give accurate prediction of pKa's for compounds containing the vinylic moiety. The hypothesis was that the effect of electron-withdrawing substituents on the pKa of p-vinyl phenols is due to the delocalized electronic structure of these compounds. Thus, this effect should be additive for multiple substituents attached to the vinylic double bond and quantifiable by LFER-based methods. The aim of this study was to produce an improved equation with a reduced tendency to underestimate the effect of the double bond on the ionisation of the phenolic hydroxyl. To this end a set of 19 para-substituted vinyl phenols was used. The ionisation constants were measured potentiometrically, and a training set of 10 compounds was selected to build a regression model (r2 = 0.987 and S.E. = 0.09). The average error with an external test set of six compounds was 0.19 for our model and 1.27 for the ACD-labs 7.0. Thus, we have been able to significantly improve the existing model for prediction of the ionisation constants of substituted p-vinyl phenols.
Isolation and Activity of N-p-Coumaroyltyramine, an α-Glucosidase Inhibitor in Welsh Onion (Allium fistulosum)
Nishioka, Tetsuo,Watanabe, Jun,Kawabata, Jun,Niki, Ryoya
, p. 1138 - 1141 (2007/10/03)
A phenolic amide, N-p-coumaroyltyramine (1), was isolated as an α-glucosidase inhibitor from methanol extracts of Welsh onion (Allium fistulosum). The inhibitory activity of 1 against a yeast enzyme was as high as Ki 8.4 × 10-7 M. From a structure-activity relationship study of 1 and its related compounds, the occurrence of α-glucosidase inhibitory activity required a p-coumaramide structure, with an amide hydrogen and alkyl or aralkyl substituent on the amide part.
COMPARATIVE REACTIVITY OF NITRILES OF PARA-SUBSTITUTED CINNAMIC ACIDS IN THE ALKYLATION OF BENZENE IN THE PRESENCE OF ALUMINUM CHLORIDE
Grebenyuk, A. D.,Grinshpun, V. D.,L'vov, V. M.
, p. 732 - 736 (2007/10/02)
The relative rate constants for the reactions of the nitriles of p-methoxy, p-methyl, and p-chlorocinnamic acids with benzene in the presence of aluminum chloride were determined by the method of competing reactions in relation to cinnamonitrile.The negative sign of ρ indicates that the electrophilic stage of complex formation between the unsaturated nitrile and aluminum chloride has a deciding role in the alkylation process.
