2-chlorovinyl

Photochemistry. Vinyl chloride is subject to photodissociation. Photexcitation at 193 nm results in the elimination of HCl molecules and Cl atoms in an approximately 1.1 1 ratio (69). Both vinyUdene ( B2) [2143-69-3] and acetylene have been observed as photolysis products (70), as have H2 molecules (71) and H atoms [12385-13-6] (72). HCl and vinyUdene appear to be formed via a concerted 1,1 elimination from excited vinyl chloride (70). An adiabatic recoil mechanism seems likely for Cl atom elimination (73). As expected from the relative stabiUties of the 1- and 2-chlorovinyl radicals [50663-45-1 and 57095-76-8], H atoms are preferentially produced by detachment from the P carbon (72). Finally, a migration mechanism appears to play a significant role in H2 elimination (71). 

E)-2-Chlorovinyl phenyl ketone (1.83 g, 11 mmol) and triisopropyl phosphite (2.08 g, 10 mmol) were heated under an argon atmosphere for 1 h at 120 to 130°C. When all of the isopropyl chloride formed had distilled, the residue was chromatographed on a column of silica gel (18 g) being eluted with a 1 1 mixture of methylene chloride-ethyl acetate. The eluent was evaporated of solvent and the residue vacuum distilled to give pure diisopropyl (E)-2-benzoylvinylphosphonate (1.33 g, 45%). 

Arsine, (2-chlorovinyl) dichloro-Arsonous dichloride, (2-chloroethenyl)... 

Dot Marking Toxic liquids, n.o.s. Dichloro-(2-chlorovinyl)arsine UN 2810 Dot Placard Poison... 

Dichloro (2-chlorovinyl) arsine C1CH = CHAsC12 7.1 times heavier than air None... 

Lewisite (L, 2Cchloroviny Idichloroarsine, 2-chlorovinyl arsonous dichloride) Vesicant — blister agent with Arsenic 30-50 mg/Kg (skin) Highly persistent because of Arsenic in formulation... 

Electrophilic addition to 9-vinylcarbazole occurs in the Markovnikov sense, thus hydrogen chloride,hydrogen bromide,chlorine, and bromine in carbon tetrachloride, and iodine chloride in pyridine are recorded as adding with initial electrophilic attack at the methylene. Mercuric acetate in methanol gave 9-(2-acetoxymercuri-l-methoxyethyl)carbazole. Although 9-vinylcarbazole gave an iodohydrin, comparable reaction with methanolic sodium hypochlorite led to 9-(2-chlorovinyl)carbazole. Catalytic reduction of the latter produced 9-(2-chloroethyl)carbazole. Tri-phenyltin hydride gave 96. ... 

Other organoarsenicals, most notably lewisite (dichloro[2-chlorovinyl]arsine), were developed in the early twentieth century as chemical warfare agents. Arsenic trioxide was reintroduced into the United States Pharmacopeia in 2000 as an orphan drug for the treatment of relapsed acute promyelocytic leukemia and is finding expanded use in experimental cancer treatment protocols (see Chapter 54). Melarsoprol, another trivalent arsenical, is used in the treatment of advanced African trypanosomiasis (see Chapter 52). 

Pyrimido[2,l -a]isoquinolinium perchlorates (316) were obtained in the reactions of 1-aminoisoquinoline and /3-diketones in acetic acid at 260°C for 2 h in sealed tubes and with phenyl and methyl 2-chlorovinyl ketones in acetic acid at 100°C for 5-10 min, then treatment with perchloric acid (74KGS1148). 

Chlorovinyl ketones and related compounds also react with active methylene compounds to form pyran-2-ones, via the unsaturated keto acid derivative (61T63). 

Similarly, 1,1-dioxides are formed either by the cyclodehydration of diacylsulfones and ammonia (Scheme 115) (720S(52)135) or through the action of sodamide on bis(2-chlorovinyl) sulfones (255) which are themselves obtained by a two-step sequence from alkynes (Scheme 116) (72S311). A less general route involves the addition of the thiirene sulfone (256) to the mesoionic oxazolone (257). In this example the initial adduct (258) eliminates carbon dioxide spontaneously, thus affording the 1,4-thiazine (259) (75CL1153). 

Lewisite 1 per se is never found in the environment. Figure 18 shows that this compound hydrolyzes rapidly on contact with moisture to 2-chlorovinyl arsonous acid, which in turn slowly dehydrates to lewisite oxide (syn. 2-chlorovinyl arsenous oxide) (16). Both 2-chlorovinyl arsonous acid and lewisite oxide are nonvolatile. The most frequently used method for the identification of CWC-related chemicals is based on gas chromatography (GC) in combination with mass spectrometry (GC/MS). Indirect GC/MS analysis of lewisite 1 requires sample preparation, which involves conversion of lewisite oxide to 2-chlorovinyl arsonous acid in an acidic environment, followed by derivatization (12). The obtained species is both volatile and thermally stable, and thus amenable to GC analysis. Often, a mercaptan reagent is used as a derivatization agent. The reaction with 3,4-dimercaptotoluene is shown in Figure 19. 

Figure 19. Formation of cyclic disulfide derivative of 2-chlorovinyl arsonous acid using 3,4-dimercaptotoluene (16)...

Bis(2-chloroethylthio)pentane Bis(2-chloroethylthiomethyl)ether Bis(2-chloroethylthioethyl)ether 2-Chlorovinyldichloroarsine Bis(2-chlorovinyl)chloroarsine Tris(2-chlorovinyl)arsine Bis(2-chloroethyl)ethylamine Bis(2-chloroethyl)methylamine Tris(2-chloroethyl)amine... 

A special derivatization reaction is required for lewisite 1, which is so reactive that it cannot be determined by GC/MS in low quantities (e.g. below 10 ng per injection). It has been known for a long time that lewisite 1 reacts with compounds having an a, P-dithiol structure, such as 2,3-dimercaptopropanol-l (British-Anti-Lewisite (BAL) also used for medical treatment). The derivatization reaction can be performed at an analytical level and several examples have been described (29). The reaction product of lewisite 1 with 3,4-dimercaptotoluene, 2-(2-chlorovinyl)-5-methyl-l,3,2-benzodithiarsole (see (1)), is a useful derivative for GC/MS analysis. Its mass spectrum is simple with molecular ion peaks at m/z 290/292 and the base peak at m/z 229 due to the loss of the 2-chlorovinyl group (30). 

Lewisite is too reactive to be analyzed by LC. Even with GC, it leads to a rapid degradation of column performance. Lewisites 1 and 2 initially hydrolyze to 2-chlorovinylarsonous acid (CVAA) (26) and bis(2-chlorovinyl)arsenous acid (28), respectively. LC/MS analysis of these trivalent acids is problematic, giving very poor signal-to-noise ratios in both... 

T.P. Logan, J.R. Smith, E.M. Jakubowski and R.E. Nielson, Verification of Lewisite exposure by the analysis of 2-chlorovinyl arsonous acid in urine, Toxicol. Methods, 9, 275-284 (1999). 

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