2-Chloroethyl cation

The high-yield dealkylation with ACE-CI is therefore very surprising. Presumably, the -CHCI-CH3 unit is too hindered to undergo competitive SN2 attack by O and the 1-chloroethyl cation generated by an alternative SN., (E.,) cleavage must be too unstable. Because the substituent is electron withdrawing, ACE-CI is more reactive toward tertiary amines than simple alkyl chloroformates. 

Nucleic acids are anionic under the neutral conditions. Thus, the syntheses of model compounds of the opposite charge are interesting for the discussion of electrostatic contributions in specific interactions of nucleic acids. We have tried to synthesize cationic models by the Menschutkin reaction of poly-4-vinylpyridine with 9-(2-chlo-roethyl)adenine, l-(2-chloroethyl)thymine, and 7-(2-chloroethyl)theophylline15,16 The obtained polymers are poly l-[2-(adenin-9-yl)ethyl]-4-pyridinioethylene chloride 7(APVP), poly l-[2-(thymin-l-yl)ethyl]-4-pyridinioethylene chloride 8 (TPVP), and poly l-[2-(theophyllin-7-yl)ethyl]-4-pyridiniothylene chloride 9 (THPVP), respectively. 

The interaction between H+, Li+, and Na+ cations and nitrosourea, as well as methyl, ethyl, and chloroethyl di azohydroxides (E and Z isomers) has been investigated with ab initio calculations, using the STO-6G and the 3-21G basis sets.13 The resulting affinities show... 

This is the third report on attempts to measure the propagation rate constant, kp+, for the cationic polymerisation of various monomers in nitrobenzene by reaction calorimetry. The first two were concerned with acenaphthylene (ACN) [1, 2] and styrene [2]. The present work is concerned with attempts to extend the method to more rapidly polymerising monomers. With these we were working at the limits of the calorimetric technique [3] and therefore consistent kinetic results could be obtained only for indene and for phenyl vinyl ether (PhViE), the slowest of the vinyl ethers 2-chloroethyl vinyl ether (CEViE) proved to be so reactive that only a rough estimate of kp+ could be obtained. Most of our results were obtained with 4-chlorobenzoyl hexafluoroantimonate (1), and some with tris-(4-chlorophenyl)methyl hexafluorophosphate (2). A general discussion of the significance of all the kp values obtained in this work is presented. 

This article reports on the synthesis of photosensitive polymers with pendant cinnamic ester moieties and suitable photosensitizer groups by cationic copolymerizations of 2-(cinnamoyloxy)ethyl vinyl ether (CEVE) (12) with other vinyl ethers containing photosensitizer groups, and by cationic polymerization of 2-chloroethyl vinyl ether (CVE) followed by substitution reactions of the resulting poly (2-chloroethyl vinyl ether) (PCVE) with salts of photosensitizer compounds and potassium cinnamate using a phase transfer catalyst in an aprotic polar solvent. The photochemical reactivity of the obtained polymers was also investigated. 

Trichloroethylene is metabolized similarly and gives rise to dichlorovinyl cysteine. It has been found that S-(l,2-dichlorovinyl)-L-cysteine (DCVC) and S-(2-chloroethyl)-DL-cysteine (CEC) (Fig. 7.30) are both nephrotoxic when administered to animals causing renal proximal tubular necrosis. CEC does not require 3-lyase activation to be nephrotoxic, but can rearrange, possibly to a reactive episulfonium ion, by nucleophilic displacement of the chlorine atom. These compounds decrease the activity of the renal tubular anion and cation transport system. 

Apart from some experiments with methyl and /i-chloroethyl vinyl ethers the initiator concentrations employed were such that the initiating cations, and presumably the propagating species, were essentially dissociated from the corresponding counterion. Once again therefore this data is a measure of the reactivity of the free polymeric cations derived from the various monomers. Isobutyl vinyl ether is the monomer most widely studied, and as would be anticipated for free cationic reactivities, the data varies little with the counterion employed (SbClg or BF4), or indeed with the carbocation used as initiator (C7H7 or Ph3C+) under similar experimental conditions. 

Several dyes have been found to sensitize the cationic polymerization of cyclohexene oxide, epichlorohydrin, and 2-chloroethyl vinyl ether initiated by diaryliodonium salts (109,110). Acridinium dyes such as acridine orange and acridine yellow were found to be effective sensitizers. One example of a benzothiazolium dye (setoflavin T) was also reported, but no other class of dye nor any other example of a dye absorbing at longer wavelengths were discovered. Crivello and Lam favored a sensitization mechanism in which direct energy transfer from the dye to the diaryliodonium salt occurred. Pappas (12,106) provided evidence that both energy transfer and electron transfer sensitization were feasible in this system. 

The various derivatives of (2-chloroethyl)trimethylammonium chloride have been considered as analogs of choline in which the alcohol group has been designated as X. The general formula of this cation would be CH2X—CH2—N + (CH3) 3. 

The enzyme choline esterase has been shown to have two binding points on its protein surface for these substances—one site for the quaternary ammonium group and one for X. This enzyme catalyzes the hydrolysis of an ester at the X position. From a consideration of the structure of the (2-chloroethyl)trimethylammonium chloride derivatives which were active as plant growth substances, a similar protein-binding site in the plant has been postulated. This site would have a point of attachment for both the ammonium cation and the X constituent of the molecule. This postulated site in the plant is thus similar, but not identical, to cholinesterase, which is an enzyme not known to occur in plants. There is no direct proof for this hypothetical site in the plant. 

Reaction of the sandwich-type POM [(Fc(0H2)2)j(A-a-PW9034)2 9 with a colloidal suspension of silica/alumina nanopartides ((Si/A102)Cl) resulted in the production of a novel supported POM catalyst [146-148]. In this case, about 58 POM molecules per cationic silica/alumina nanoparticle were electrostatically stabilized on the surface. The aerobic oxidation of 2-chloroethyl ethyl sulfide (mustard simulant) to the corresponding harmless sulfoxide proceeded efficiently in the presence of the heterogeneous catalyst and the catalytic activity of the heterogeneous catalyst was much higher than that of the parent POM. In addition, this catalytic activity was much enhanced when binary cupric triflate and nitrate [Cu(OTf)2/Cu(N03)2 = 1.5] were also present [148],... 

Dialkylanilines that bear a cationic substituent at one of the alkyl groups are among the most important coupling components of cationic azo dyes. By reaction of iV-ethyl-iV-(2-chloroethyl)aniline or of N-ethyl- N-(2-chlo roethy 1)- w-toluidine with trimethylamine, ammonium salts are obtained that, upon coupling with dia-zotized aromatic amines, yield a large number of valuable dyes for coloring polyacrylonitrile. Red shades with a blue cast are obtained with 2-cyano-4-nitroani-line as the diazo component. 

By treating dyes that contain a chloroethyl group with thiourea, the cationic charge may be introduced in the form of an isothiouronium residue (e.g., 55) [150],... 

Diffiuex investigated a synthesis of cyclic poly(vinyl ether) using cationic polymerization [26,28]. The reaction process is depicted in Fig. 9. They studied on the living cationic polymerization of 2-chloroethyl vinyl ether (CEVE) initiated with the HI adduct of 4-(vinylbenzyloxy)butyl vinyl ether prepared by reacting chloromethyl styrene with sodium salt of 4-hydroxy-butyl vinyl ether in THF at 80 °C. By the cationic polymerization of CEVE, o /o-hetcrofunclional linear polymer precursor of cyclic poly(CEVE) was produced. The MWDs of the polymers were unimodal and very narrow (< 1.2),... 

On standing, LXXIXb undergoes a rearrangement, apparently with the formation of an iminium cation (LXXX)—a reaction analogous to the formation of an ethyleneiminium cation from V-alkyl-V,./V -bis(2-chloroethyl)-amine.184 The di-O-mesyl ester (LXXXI) of LXXVIII is remarkably resistant to catalytic de-O-acetylation. 

Cationic and amphoteric Surfmers were synthesized from the hemi ester or hemi amide with a C12-C20 alkyl chain and diethyl (chloroethyl) amine followed by quaternization with conventional agents or by reaction with propanesultone [23]. 

R. Bartnik and B. Kryczka, Synthesis of cationic dyes by the condensation of 1-chloroethyl- and 1-hydroxyethyl-2-formyl-methylene-3,3-dimethylindolines with indoles in acetic acid., Chem. Stosow., 34, 335-342 (1990). 

Cationic model compounds of polynucleotide such as 62 and 63 were prepared by the Menschutkin reaction of poly-4-vinylpyridine with 9-(2-chloroethyl)adenine and l-(2-chloroethyOthymine80, M>. 

Since the development of living cationic polymerizations of alkyl vinyl ethers (Chapter 4, Sections IV and V.A), considerable efforts have been made to synthesize and polymerize vinyl ether derivatives carrying polar functional substituents, and thereby it is now possible to obtain a variety of pendant-functionalized poly(viny) ethers) of controlled molecular weights and narrow MWDs [1,2,13], Figure 3 lists typical examples of vinyl ethers carrying various pendant functionalities for which living cationic polymerizations are available [14-35]. These monomers are synthesized most conveniently from 2-chloroethyl vinyl ether, now commercially available,... 

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