The half-neutralization potentials (HNP) of a series of biologically active fluoromethanesulfonamides were determined in 67% N, N-dimethylformamide-water. A plot of aqueous pKa vs. HNP for nine methanesulfonamides and fluoromethanesulfonamides in the series was used to calculate the pKa's of the remaining water-insoluble sulfonamides. The pKa's of eight aryl-substituted 1,1,1 -trifluoro-lV-phenylmethanesulfonamides correlated better with the Hammett substituent constant than with ~or
The rates of nitrogen inversion have been measured with nuclear magnetic resonance (nmr) techniques in a series of aziridines substituted on nitrogen with a series of functional groups centered around sulfur and phosphorus. The rates of nitrogen inversion assumed the following order: 1 -diphenylphosphinoxyaziridine » 1benzenesulfonylaziridine > l-(2,4-dinitrobenzenesulfenyl)aziridine > 1 -benzenesulfenylaziridine > 1-benzenesulfinylaziridine. The rate order is discussed in terms of steric conjugative (or overlap), inductive, and electrostatic effects. No relationship is visible between the configuration-holding power of the group X in aziridine system (CH2}¡NX and in the carbanion system R2CX. Thus, amines appear to be unsatisfactory models for carbanions as far as substituent effects that control stereochemistry are concerned. It is concluded that electrostatic effects in the charged anions which are absent in the neutral aziridines dominate the stereochemistry of carbanions substituted with these functional groups. The nmr spectra of the aziridines were interpreted.
or toxicological symptoms and all the birds remained healthy throughout the study. Feed consumption was significantly reduced at the 300 g/ton level and the birds in this group ended th$ medication period gaining 60% as much weight as the control group. There were no discernible differences in the quality of the eggs or the egg shell.
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