Shedlovsky's results,16 which differ from all others. There can be no doubt that most if not all, of these minima are spurious. One observation, which we have made may have an important bearing on this problem. In many cases, on addition of the first sample, the resistance of the solution drifted to lower values. The rate of this drift depended on the salt as well. as on the sample. In some ins...

We report herein the efficiency of quaternary ammonium salts as co-catalysts in organocatalytic Michael reactions involving iminium activation of α,β-unsaturated aldehydes. The enantioselective formal benzylation of these substrates has been optimized and used to rationalize the role of the ammonium salts in these processes.

Two series of rosin quaternary ammonium salts (QAS) were synthesized using the same path. The structure of the target products was characterized by HPLC, MS, IR, and 1 HNMR, and the bioactivity was determined by filter paper method using Trametes versicolor (white-rot fungus) and Gloeophyllum trabeum (brown-rot fungus), which are two kinds of general wood decay fungi in nature. The results show...

With the specialty of improving the water solubility of chitosan, quaternary ammonium salts have broadened the application of this polysaccharide in food, medicine and pesticides. To identify the effect of quaternary ammonium salts' quantity, single quaternized chitosan N-phenmethyl-N,N-dimethyl chitosan (PDCS), double quaternized chitosan N-(1-pyridylmethyl-2-ylmethyl)-N,N-dimethyl chitosan (M...

An in situ IR technique was applied in the selective synthesis of the key intermediate for rapamycin derivatives, which made the reaction endpoint easily defined. This technology solved a bothersome problem in the preparation of rapamycin derivatives, and based on this technique, the 31-OH and 42-OH of rapamycin were chemically modified by a series of quaternary ammonium salts to generate 11 co...

A series of porous polymers bearing functional quaternary ammonium salts were solvothermally synthesized through the free radical copolymerization of divinylbenzene (DVB) and functionalized quaternary ammonium salts. The obtained polymers feature highly cross-linked matrices, large surface areas, and abundant halogen anions. These polymers were evaluated as heterogeneous catalysts for the synth...

Derivatization of peptides as quaternary ammonium salts (QAS) is a promising method for sensitive detection by electrospray ionization tandem mass spectrometry (Cydzik et al. J. Pept. Sci. 2011, 17, 445-453). The peptides derivatized by QAS at their N-termini undergo fragmentation according to the two competing mechanisms - charge remote (ChR) and charge directed (ChD). The absence of mobile pr...