Quarternization

So-called delocalized cationic azo dyes are another type ia which the positive charge is delocalized (or distributed) across the dye cation. Basic Blue 54 (132) (2-amiao-6-methoxybenzothiazole coupled to /V, /V-dimethy1 ani1 ine and then quarternized with dimethyl sulfate) is an example of this class which can also be considered as a diazamethine dye. 

The benzofurazans can be oxidized or form the quaternary salts. For example, phenantro-l,2,5-oxadiazine 32 was readily quarternized to iV-methylazolium salt on being heated in dimethyl sulfate. Anion exchange with sodium perchlorate gave high yields of the phenanthroazolium perchlorate salts 33 (Equation 7) <1997J(P1)1047>. 

Amino-5-methyl-l,3,4-thiadiazole 48 reacts with chloroacetone to give the N-alkylated thiadiazolimine 49 (Equation 4) <2000AF550> and iV-alkylation of the 2,5-diphenyl- and 2,5-dimethyl-l,3,4-thiadiazole 50a and 50b with trimethylsilylmethyl trifluoromethanesulfonate gave the corresponding 1,3,4-thiadiazolium salts 51 (Equation 5) <2002J(P 1)2851 >. A comprehensive study of the quarternization of the 2,5-disubstituted thiadiazoles has been covered in CHEC(1984) <1984CHEC(6)545>. 

Quarternization of the triazole (5) gave the betaine (6) which is in tautomeric equilibrium with (6a) (Scheme 1). 

As carriers for ion exchangers they find application in HPLC. Cation exchangers are prepared by sulfonation, anion exchangers are prepared by nitration. Reduction to amines and alkylation, are achieved through quarternation and chloromethylation, respectively. 

Fig. 11 Visualization of the sequential progress of branching stage by staining with rose bengal. DC-derivatized PST surface (GO) was graft-copolymerized with CMS and dimethylaminoethyl acrylamide (DMAEMA), and subsequent quarternization, while narrowing the irradiation area in each polymerization stage (item, GI item, GI+GII item, GI+GII- -GIII) by the combination of three kinds of masks with linear openings (line widths 2 mm for GI, 1 mm for GII, 0.5 mm for GUI). Bar=0.5 mm...

Quarternization of tertiary amines causes jl and y effects which overlap with the shieldings induced by the positively charged nitrogen, as shown for some tetraalkylam-monium salts in Table 4.42 [339], Tetraalkylammonium ions display triplet splittings of 4 Hz due to 13C—14N coupling (/i[Pg.238]

Decontamination of Waters Containing Dissolved Explosive Wastes. Accdg to McDonald (Ref), decontamination may be achieved by means of a quartern ary salt of a halide of Group V, nonmetal. The general formula of such salt is R.A.M.R .R1 .R11. X, in which ... 

It has been shown19,20) that under PAA complex formation with excess of partly quaternized PYP, the latter is quite effectively fractionated by composition, macromolecules of the copolymer enriched with nonalkylated units being selected in the polycomplex. It is of importance that the preliminary molecular-weight fractioned sample of P-4-VP is quarternized with ethyl bromide, i.e., under the conditions of an experiment it is possible to consider... 

Spectroscopic and viscosity results for these quarternized PAs indicated that these polymers have effective conjugation lengths ranging from 10-16 double... 

These quarternized polymers can be viewed as self-doped but exhibit relatively low intrinsic conductivities. The polymers can be oxidatively doped with iodine, or reductively doped with TTF, to give highly conducting polyacetylenes with conductivities of 10"4 and 10 1 S/cm, respectively. One additional attractive feature of this system is that, unlike PA, these quarternized PAs are very stable in air. 

M. Yoshikawa, T. Yukoshi, K. Sanui, N. Ogata, Selective separation of water from water-ethanol solution through quarternized poly(4-vinyl pyridine-co-acrylonitrile) membranes by pervaporation technique, J. Appl. Polym. Sci. 33 (1987) 2369-2392. 

The effect of ionization on the pharmacological action of drugs was also recognized in the latter half of the nineteenth century. In Scotland, Crum Brown and Fraser demonstrated that quarternization (i.e., the addition of a fourth alkyl group) of several alkaloids resulted in their transition from muscle contractors to muscle relaxants. These researchers concluded that a relation exists between the physiological action of a substance and its chemical composition and constitution, understanding by the latter term the mutual relations of the atoms in the substance. ... 

The dependence of NMR chemical shifts on the molar ratio of complex components may be used for studies of the stoichiometry of the complex (252,256,258,263) (Fig. 1). The resonance of some nuclei of the electron donors changes considerably on complexation with silanes. Particularly large changes are observed for the 15N resonance ( 100 ppm upfield) since the paramagnetic component of the 15N-NMR chemical shift is eliminated on quarternization of nitrogen. Mixing of equimolar amounts of pyridine and triphenylsilyl perchlorate was demonstrated to lead to a shift of the 15N-NMR signal from 314.0 to 216.8 ppm, which was taken as evidence for the formation of a 1 1 ionic complex (18). 

With sodium in ethanol pyridazine is reduced to hexahydropyrida-zine 1,4-diaminobutane is also obtained.It can form quaternary salts, but no bisquaternization was found. A survey of the quarternization of pyridazines and other heterocycles is given in Volume 3, Chapter 1 of this Series. For alkylation and arylation of pyridazine see Section IV of the present chapter. 

Essigsaure Trimethylamoniono- -methylester (methylsulfonat) V/2, 449 (Quartern isier.) XI/2, 614 (Quarternisier.)... 

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