نتایج جستجو برای: quaternary ammonium compounds
تعداد نتایج: 259839 فیلتر نتایج به سال:
Markedly enhanced recyclability of osmium catalyst in asymmetric dihydroxylation has been achieved by using osmylated macroporous resins bearing both residual vinyl groups and quaternary ammonium moiety.
Lascaux Cave (Montignac, France) contains paintings from the Upper Paleolithic period. Shortly after its discovery in 1940, the cave was seriously disturbed by major destructive interventions. In 1963, the cave was closed due to algal growth on the walls. In 2001, the ceiling, walls and sediments were colonized by the fungus Fusarium solani. Later, black stains, probably of fungal origin, appea...
In many voltage-gated K(+) channels, N-type inactivation significantly accelerates the onset of C-type inactivation, but effects on recovery from inactivation are small or absent. We have exploited the Na(+) permeability of C-type-inactivated K(+) channels to characterize a strong interaction between the inactivation peptide of Kv1.4 and the C-type-inactivated state of Kv1.4 and Kv1.5. The pres...
ADAMS, M. 1952 Classification of bacterial viruses: Characteristics of the T5 species and of the T2, C16 species. J. Bacteriol., 64, 387-396. BURNET, F. M. 1929 A method of study of bacteriophage multiplication in broth. Brit. J. Exp. Pathol., 10, 109-114. CHERRY, W. B., AND WATSON, D. W. 1949 The Streptococcu8 lactis host-virus system. II. Characteristics of virus growth and the effect of elec...
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...
Decisive evidence for acetyl-choline as a chemical transmitter has accumulated during the last 20 years. Chemically acetyl.choline is a quaternary ammonium compound and it is but natural to expect that substances analogous to this chemical grouping would have actions of preserving, mimicking or antagonising the natural chemical transmitter at the receptors sensitive to it. This is found to be c...
The title compound, C(18)H(24), was the main product of thermolysis of noradamantene dimer (hepta-cyclo-[9.3.1.1(2,6).1(4,8).1(9,13).0(1,9).0(2,8)]octa-deca-ne). The crystal structure was determined to prove that the thermolysis product of noradamantene dimer is favored by stretch release due to ring opening of the four-membered ring. The bond length of the quaternary C atoms of the starting ma...
X-ray data on single crystals of the quaternary metal hydride near the composition LiB(0.33)N(0.67)H(2.67), previously identified as "Li3BN2H8", reveal that its true composition is Li4BN3H10. The structure has body-centered-cubic symmetry [space group I2(1)3, cell parameter a = 10.679(1)-10.672(1) Angstroms] and contains an ordered arrangement of BH4- and NH2- anions in the molar ratio 1:3. The...
Pentaerythritol/quaternary ammonium eutectic mixture as an ionic solvent: the quaternary ammonium cations can be easily controlled to exert their structure-directing effect in ionothermal synthesis of aluminophosphate microporous materials.
The synthesis and kinetic resolution of quaternary oxindoles through copper catalysed azide-alkyne cycloadditions is presented. Selectivity factors (s) up to 22.1 ± 0.5 are reported. Enantioenriched alkynes and triazoles were obtained in ≥80% enantiomeric excess (e.e.).
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