Trimethylammonium group

Alternatively, the Sn2 nucleophilic substitution reaction between alcohols (phenols) and organic halides under basic conditions is the classical Williamson ether synthesis. Recently, it was found that water-soluble calix[n]arenes (n = 4, 6, 8) containing trimethylammonium groups on the upper rim (e.g., calix[4]arene 5.2) were inverse phase-transfer catalysts for alkylation of alcohols and phenols with alkyl halides in aqueous NaOH solution to give the corresponding alkylated products in good-to-high yields.56... 

The water-soluble calix[n]arenes 6.3 (n = 4, 6 and 8) containing trimethylammonium groups act as efficient inverse phase-transfer catalysts in the nucleophilic substitution reaction of alkyl and arylalkyl halides with nucleophiles in water (Eq. 6.19).40 In the presence of various surfactants (cationic, zwitterionic and anionic), the reactions of different halides and ketones show that the amount of ketone alkylation is much higher and that the reactions are faster in the presence than in the absence of surfactant aggregates.41 The hydrolysis of the halide is minimized in the presence of cationic or zwitterionic surfactants. 

Kier, L.B., Aldrich, H.S. A theoretical study of receptor site models for trimethylammonium group interactions. J. Theor. Biol. 1974, 46, 529-541. 

The above speculation [21] may be extended to include the related quaternary ammonium compounds such as xylocholine (XXXIX). It is probable that the volumes of the guanidinium ion and the trimethylammonium group are similar. The ionic radius of the guanidinium ion (IX) is about 3A the ionic radius of the tetramethylammonium ion has been estimated [300] to be 3-4A, although rather smaller values have also been proposed [301-303]. Crystallographic analyses of muscarine iodide [304], choline chloride [305] and acetylcholine bromide [306] have revealed that the carbon to nitrogen distance is about l-SA, and that a hydrogen bond (C-H-0 distance 2-87-3 07A) exists in the crystals of these compounds. 

The crown ether 11 has a trimethylammonium group reaching into the interior of the cavity and is complexed intramolecularly by short CH—O hydrogen bonds. Additional hydrogen bonds between the acidified CH3 groups and the iodide anion were confirmed by X-ray analysis. 

Ligands with trimethylammonium groups can be prepared by the regio-selective addition of diphenylphosphane to conjugated alkenes with good yields. For example, the alkene CH2=CHC(0)0CH2CH2NMe3l , an acrylic ester, has been used (45). The authors did not report the water solubility. 

On the basis of the interaction of metal ions and AV-pH and AV-log C plots (41, 43), we propose ionic structures for dioleoyl, egg, and di-palmitoyl lecithin monolayers represented in Figure 1. Schematically shown in Figure 1A is the internal salt linkage between the phosphate and trimethylammonium groups in dioleoyl lecithin, preventing the inter-... 

A Dioleoyl lecithin shows internal salt linkage between phosphate and trimethyl-ammonium groups. Broken lines in egg lecithin diagram represents weak interactions of phosphate with Ca2+ and trimethylammonium group. Solid line between Ca + and phosphate group in dipalmitoyl lecithin diagram represents strong interaction... 

Phosphatidic Acid Monolayers. Phosphatidic acid, prepared from egg lecithin by the action of phospholipase D, forms considerably more expanded monolayers than egg lecithin, presumably because of ionic repulsion between the phosphate groups in the phosphatidic acid mono-layers (42). Phosphatidic acid monolayers showed about four times more increase in surface potential when CaCl2 is substituted for NaCl in the subsolution than did egg lecithin monolayers (43). This again supports the conclusion that the trimethylammonium group competes with Ca2+ for the anionic phosphate group in egg lecithin monolayers (Figure 1A). 

The interaction of metal ions with lecithin monolayers, as measured by the increase in surface potential, decreases with increasing unsaturation of fatty acyl chains. The phosphate and trimethylammonium groups of a lecithin molecule form an internal salt linkage which dissociates upon... 

The Friedel-Crafts acylation of acetanilide with chloroacetyl chloride yields l-acetamido-4-chloroacetylbenzene. The trimethylammonium group is introduced by reaction with trimethylamine, followed by hydrolysis of the acetamide group. This diazo component is a constituent of numerous yellow, orange, and red cationic azo dyes. Using diethyl- m-toluidine as the coupling component, the lightfast red dye 35 [67905-12-8] is obtained [99],... 

Arena, G., Casnati, A., Contino, A., Lombardo, G. G., Sciotto, D., and Ungaro, R. (1999) Water-soluble calixarene hosts that specifically recognize the trimethylammonium group or the benzene ring of aromatic... 

Using an elegant approach, Che et al. prepared chiral mesoporous silica using bio-inspired surfactants [63]. The trimethylammonium group of the quaternary amine used as a surfactant in the synthesis of MCM-41 (CTAB) was replaced by L-alanine. The chirality of the amino acid in the polar head of the surfactant induces chirality in the micelle used as template (see Figure 3.15). This simple modification in the surfactant allowed the preparation of the first chiral mesoporous silica with tunable pore size and ordered porosity. A key step in this synthesis is the transfer of the chirality from the surfactant to the solid, which was accomplished by electrostatic interaction between the terminal amino acid and the... 

In another 1H-NMR study, the interaction of P-blockers with sonicated DMPC liposomes in the presence of Pr3+ was evaluated [122]. The presence of Pr3+ increased the splitting of the choline trimethylammonium group signals that arise from the phospholipid molecules located at the internal and external layer of the bilayer. The downfield shift of the external peak ( ) is considerably stronger than the upheld shift of the internal peak (i) (Figure 3.34). The difference in chemical shift of the two sig-... 

The oxidative decarboxylation of a cyclohepta[c c ]dithiophene (40), or the elimination of the trimethylammonium group in the salt (41) gave the fused cycloheptatriene (42) <82CS53>. However, in contrast to the isomeric system (43), a tropylium ion could not be formed from compound (42) <81JCS(P1)2904>. 

Figure 6.Schematic localization of hexamethonium ions in ZSM-48 channel structure, generating SiO- defects near the terminal trimethylammonium groups of the template.

Conversion to Other Zeolites, A key question regards the significance of the trimethylammonium group on the template for the conversion of Cubic P. Table II contains the templates studied in this connection TMA causes conversion to the organozeolite sodalite and at a rate comparable to most of the conversions to SSZ-13 shown in Figure 2 The rates for this second portion of the study are shown in Figure 5, based on pH measurements. Products in this portion are generally of the pentasil class. Rates of the templates other than TMA and TEA were relatively slow. TEA produced mostly mordenite plus a little beta. 

Diquat 6 produced mordenite, but at a slow rate in spite of having trimethylammonium groups. In conventional synthesis and at Al/Si of 0.02 to 0.07, Diquat 6 is quite efficient in producing EU-1 (12) but in the present synthesis starting with Cubic P, the conversion was slow and no EU-1 was made ... 

A number of templates having the trimethylammonium group attached to a cyclohexane ring (and derivatives thereof) produce the high silica chabazite, SSZ-13. The rate of conversion of Cubic P to SSZ-13 increases as the nonpolar group increases in size up to C group. 

The iV,N,N-trimethylammonium group, -N(CIT3)3, is one of the few groups that is a meta-directing deactivator yet has no electron-withdrawing resonance effect. Explain. 

A 7a trimethylammonium group (10) is in a state of compression with sy -axial hydrogen atoms, and the iodide undergoes thermal decomposition to give the A -olefin (ii) under neutral conditions [38], This reaction presumably gives the... 

Since direct substitution of 4-chloroquinazolines with cyanide without a suitable catalyst has no preparative value (cf. p 131), displacement of the 4- or 2-trimethylammonium group in 1 with cyanide using potassium cyanide or tetraethylammonium cyanide is the most convenient method for the preparation of quinazoline-4-carbonitriles 2B and quinazoline-2-carbonitriles 2A, respectively. Trimethylquinazolinylammonium chlorides are easily obtained from respective chloroquinazolines and trimethylamine. ... 

Chiral ferrocenyl derivatives with a trimethylammonium group in the a-position are known to undergo nucleophilic substitution with complete retention of configuration [2]. Quaternization of 3 with methyl iodide followed by reaction with iV-methylethanolamine, (S)-prolinol, or (lS,2R)-ephedrine gave the corresponding (R,S)-2-iodoferrocenes 4a, 4b, and 4c in 80 — 90% yield with complete retention of configuration (Scheme 3-4). Diastereomers 4d and 4e were similarly prepared starting with (S,R)-3. 

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