A series containing twelve substituted styryl 2-phenothiazenyl ketones have been synthesized. The electrochemical potentials of carbonyl and vinyl groups were measured. These potentials are correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses, the effects of substituent on the group reduction potentials have been discussed. The insect antif...

Hydrogen bond strength in host-guest systems is modulated by many factors including preorganization, steric effects, and electronic effects. To investigate how electronic effects impact barbiturate binding in bifurcated Hamilton receptors, a library of receptors with differing electronic substituents was synthesized and (1)H NMR titrations were performed with diethyl barbital. The Hammett plot ...

12 CLR 2015-2016 | MLO | www.clr-online.com Th e concept of critical values for drug levels was originally developed by the late Daniel M. Baer, MD, and fi rst published in the April 1982 issue of MLO. Th is table is an expanded version of that publication and newly revised for 2015-2016 by Catherine A. Hammett-Stabler, PhD, DABCC, FACB, Professor of Pathology, Director of Core Laboratories at ...

A catalytic, enantioselective formal synthesis of (+)-dichroanone and (+)-taiwaniaquinone H is reported. The all-carbon quaternary stereocenter was constructed by asymmetric conjugate addition catalyzed by a palladium(II) (S)-tert-butylpyridinooxazoline complex. The unexpected formation of a [3.2.1] bicyclic intermediate required the identification of a new route. Analysis of the Hammett consta...

Three new protic ionic liquids based on 2-methylpyridinium were prepared and characterized. Their catalytic activities for the tert-butylation of phenol and the esterification of cyclic olefins with acetic acid were examined and satisfactory results were obtained over 2-methylpyridinium trifluoromethanesulfonate ([2-MPyH]OTf). Hammett method was used to determine the acidity order of these ioni...

[structure: see text] The trans/cis ratio of the amide bond in N-formylproline phenylesters correlates with electron withdrawal by a para substituent. The slope of the Hammett plot (rho = 0.26) is indicative of a substantial effect. This effect arises from a favorable n --> pi interaction between the amide oxygen and ester carbonyl. In a polypeptide chain, an analogous interaction can stabilize...

The pKAH-values of some substituted phenylacetic acid derivatives have been determined in the system water /dimethyl sulphoxide / 0. 11 M tetramethylammonium hydroxide. The acidity depends strongly on the polarity of the substituent in the phenyl group, Hammett p-valucs from 4.8 to 5 .8, and in the case of the same s<1bstituent decreasf's in the order nit! ik, terr-butyl ester, dimethylami<'e e...