Chloromethane generation with

Zinc chloride is also a catalyst for a liquid-phase process using concentrated hydrochloric acid at 100-150°C. Hydrochloric acid may be generated in situ by reacting sodium chloride with sulfuric acid. As mentioned earlier, methyl chloride may also be produced directly from methane with other chloromethanes. However, methyl chloride from methanol may be further chlorinated to produce dichloromethane, chloroform, and carbon tetrachloride. 

When benzene is alkylated, it reacts with a haloalkane in the presence of aluminium chloride as a catalyst. In the example shown, chloromethane is used and the electrophile CH is generated from its reaction with aluminium chloride ... 

Propagation. In this step, the intermediate reacts with a stable molecule to produce another reactive intermediate and a product molecule. The propagation step yields a new electrophilic species, the methyl radical, which has an unpaired electron. In a second propagation step, the methyl radical abstracts a chlorine atom from a chloromethane molecule, and generates a chlorine radical. 

More recently, sulfide oxidations with [hydroxy(tosyloxy)iodo]benzene (4, HTIB) have been reported [15]. Such reactions proceed readily in di-chloromethane at room temperature and stop at the sulfoxide stage (Scheme 2). HTIB can also be generated in situ from iodosylbenzene (5) and 10 mol% p-toluenesulfonic acid for catalytic oxidations of sulfides to sulfoxides [16]. Oxidations of unsymmetrical sulfides with the chiral (+)-10-camphorsulfonyloxy analog of HTIB afford the corresponding sulfoxides (82-92%) with low enan-tioselectivities (2.7-13.7% ee) [15]. 

Hydrostannation of carbonyl compounds with tributyltin hydride is promoted by radical initiation and Lewis or protic acid catalysis.The activation of the carbonyl group by the acidic species allows the weakly nucleophilic tin hydride to react via a polar mechanism. Silica gel was a suitable catalyst allowing chemoselective reduction of carbonyl groups under conditions that left many functional groups unchanged. Tributyltin triflate generated in situ from the tin hydride and triflic acid was a particularly efficient catalyst for the reduction of aldehydes and ketones with tributyltin hydride in benzene or 1,2-di-chloromethane at room temperature. Esters and ketals were not affected under these conditions and certain aldehydes were reduced selectively in preference to ketones. 

Cyclopropaniminium salts have been prepared in solution from cyclopropane-1,1-diamines by addition of methyl fluorosulfate, - bromine in liquid sulfur dioxide or dimethylchloronium tetrafluoroantimonate in liquid sulfur dioxide. Bicyclo[4.1.0]heptaniminium salts were obtained in fluorosulfonic acid at — 60 °C from a bicyclo[4.1.0]heptanone aminal or hemiaminal precursor or by the reaction of the corresponding aminal and methyl fluorosulfate in chloroform. A free cyclopropaniminium ion in solution also was assumed to be generated by the interaction of cyclopropanone hemiaminal with titanium(IV) chloride at — 78°C in di-chloromethane. ... 

Phenylthiocarbene, generated by phase-transfer catalysis from (phenylthio)chloromethane adds stereospecifically to ( )-1,2-diphenylethene to provide, 2-trans-2,3-cis-, 2-diphenyl-3-(phenylthio)cyclopropane1. The simple diastereoselectivity of reactions with olefins such as cyclohexene and phenylethene is moderate to good, favoring the endo- or cis-products. For further examples of sulfur-substituted carbenes, see Houben-Weyl Vol. E 19b, pp 1682-1745. 

The anions of N-acyl-2-chloropyridin-3-amines, generated by sodium hydride in dimethylform-amide, condense with. r-(/i-chloroalkyl)-/ /,A -dimethy]amines to afford 1-acyl-4-methyl-l,2,3,4-tetrahydropyrido[2,3-7>]pyrazines 17.17 The reaction presumably proceeds with loss of chloromethane. 

OXYBIS (CHLOROMETHANE) (542-88-1) Forms explosive mixture with air (flash point <66°F/<19°C). Contact with water causes decomposition and the formation of hydrogen chloride. Forms unstable peroxides. Contact with oxidizers, peroxides, sunlight may form shock-sensitive compounds. Attacks many plastics, coatings. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

B.vii. Halocarbenes. Polyhalomethanes can be converted to halocarbenes via photolysis, thermolysis, or treatment with base. When cyclohexene was treated with a mixture of chloromethane and phenylsodium, methylene ( CH2) was formed, and it added to the alkene gave norcarane (336), but in only 3.2% yield.268 Obviously, chloromethane is not the best source of carbenes. Polyhalomethanes give much better results, and the most common method for generating halocarbenes is treatment of dihalomethanes and trihalomethanes with sodium metal or with another base.269... 

The action of a solution of potash in amyl alcohol on rutaecarpine produces anthranilic acid and a second acid which, when boiled with hydrochloric acid, is readily decarboxylated to tryptamine (6, 25, 94, 134, 135, 169). A close relationship between rutaecarpine and evodiamine was demonstrated by fusion of isoevodiamine hydrochloride. Rutaecarpine was formed with liberation of chloromethane. A number of syntheses of (63) have been reported 101, 135, 161), including some under so-called physiological conditions. Some of the more recent examples will be mentioned. Kametani et al. 102,108) obtained (63) in 80% yield through a regiospecificH s+n s cycloaddition of a keteneimine (generated in situ by extrusion of sulfur dioxide from the sulfmamide anhydride of anthranilic acid) with 3,4-dihydro-p-carboline or with 1,2,3,4-tetrahydro-l-keto-P-carboline 109) (also called 1,2,3,4-tetrahydronorharman-l-one or, as in Chemical Abstracts, 2,3,4,9-tetrahydro-lH-pyrido[3,4-b]indol-l-one) ac-... 

Another factor to be considered is whether the compounds of the right side of the equation (by definition, the products) are more reactive (less stable) than those on the left side of the equation (normally, the reactants). If the reaction of chloromethane (11) and sodium iodide occurred, it would generate iodomethane (12) and sodium iodide. For reasons that will be apparent in Chapter 11 (Section 11.3), the iodide ion is a better nucleophile than the chloride ion, as illustrated by Figures 7.1 and 7.2. This means that the value of K for the conversion of 11 to 12 is 1 for the reaction, and the reverse reaction has a K of 1. In other words, iodine reacts with bromomethane to give product, but bromide does not react with iodomethane to give bromomethane. 

The reaction can be carried out efficiently by using aryl diazonium tetrafluoroborates with crown ethers, polyethers, or phase transfer catalysts. In solvents that can act as halogen atom donors, the radicals react to give aryl halides. Bromotri-chloromethane gives aryl bromides and methyl iodide gives iodides.Diazonium ions can also be generated by in situ methods. Under these conditions, bromoform and bromotrichloromethane have been used as bromine donors and carbon tetrachloride is the best chlorine donor. ... 

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