Chlorination butyl hypochlorite

Chlorination (-Butyl hypochlorite. N-Chiorosuccinimide. Cupric chloride. Dibenzoyl peroxide. Dimethylformamide. Phosphorus pentachloride. Phosphorus trichloride. Selenium oxychloride. Sodium chlorate. Sulfuryl chloride. Tetra- -butylammonium iodotetrachloride. N,2,4,6-Tetrachloroacetanilide. Thionyl chloride. Trichloromethanesulfonyl chloride. Triphenylphosphine dichloride. 

There are two sequences in which the reaction can be carried out. For most anilines the first step is /V-chlorination which can be done with t-butyl hypochlorite[9]. However, for anilines with ER substituents it may be preferable to halogenate the thioester. The halogenation can be done with Cl2[lbl or SOjCljCU]. For some anilines simply adding f-butyl hypochlorite to a mixture of the aniline and thioester is satisfactory (Entries 1, 4, Table 7.6). 

The kinetics of formation and hydrolysis of /-C H OCl have been investigated (262). The chemistry of alkyl hypochlorites, /-C H OCl in particular, has been extensively explored (247). /-Butyl hypochlorite reacts with a variety of olefins via a photoinduced radical chain process to give good yields of aUyflc chlorides (263). Steroid alcohols can be oxidized and chlorinated with /-C H OCl to give good yields of ketosteroids and chlorosteroids (264) (see Steroids). /-Butyl hypochlorite is a more satisfactory reagent than HOCl for /V-chlorination of amines (265). Sulfides are oxidized in excellent yields to sulfoxides without concomitant formation of sulfones (266). 2-Amino-1, 4-quinones are rapidly chlorinated at room temperature chlorination occurs specifically at the position adjacent to the amino group (267). Anhydropenicillin is converted almost quantitatively to its 6-methoxy derivative by /-C H OCl in methanol (268). Reaction of unsaturated hydroperoxides with /-C H OCl provides monocyclic and bicycHc chloroalkyl 1,2-dioxolanes. 

Uses. /-Butyl hypochlorite has been found useful in upgrading vegetable oils (273) and in the preparation of a-substituted acryflc acid esters (274) and esters of isoprene halohydrins (275). Numerous patents describe its use in cross-linking of polymers (qv) (276), in surface treatment of mbber (qv) (277), and in odor control of polymer latexes (278). It is used in the preparation of propylene oxide (qv) in high yield with Httle or no by-products (269,279). Fluoroalkyl hypochlorites are useful as insecticides, initiators for polymerizations, and bleaching and chlorinating agents (280). 

Pyridazine-3,6-diones (diazaquinones) are prepared from cyclic hydrazides by oxidation with lead tetraacetate or other oxidizing agents, such as r-butyl hypochlorite, chlorine or nickel peroxide. 

Treatment of a carborane derivative of thiirane with A-bromosuccinimide gives a j3-bromodisulfide (79MI50601). Chlorination of CM-2,3-di-f-butylthiirane by f-butyl hypochlorite proceeded differently to the reaction with chlorine itself (Scheme 41) (74JA3146). 

Another reagent which effects chlorination by a radical mechanism is f-butyl hypochlorite. The hydrogen-abstracting species in the chain mechanism is the f-butoxy radical. 

The amine hydrogens of polyfluorinated anilines can be replaced with chlorine by using tert-butyl hypochlorite [65,66]... 

The sulfur analogue of the Hauser ortho-substitution rearrangement provides access to an arylacet-ic NSAID. Reaction of the aminobenzophenone 176 with ethyl methylthioacetate and tert-butyl hypochlorite gives the intermediate 178. The reaction probably proceeds by way of formation of the S-chlorinated sulfonium derivative 177 displacement on sulfur will lead to the salt 178. Treatment with triethylamine leads initially to the betaine 179. Electrocyelic rearrangement of that transient intermediate leads, after rearomatization, to the homoanthranilic acid 180. Internal ester-amine interchange leads then to indolone 181 [45]. The thiomethyl group is then removed with Raney niekel. Saponifieation of intermediate 182 affords bromfenac (183) [46J. 

Chlorination of cyclohexylamine with i-butyl hypochlorite, 45,16 Chlorine, reaction with 2-butyne, 46, 34... 

Chain termination. The chlorination of alkanes by rm-butyl hypochlorite is believed to follow a chain mechanism, but there is a dispute about the termination step.10 Derive the steady-state rate equation for each, making the long-chain approximation. 

Chloroanthracene has been prepared by the action of chlorine,2 tert-butyl hypochlorite, l,3-dichloro-5,5-dimethylhy-dantoin, or phosphorus pentachloride 5 on anthracene. 

Our own earlier work on the chlorination of toluene had been subject to similar constraints. In this case, chlorination with ferf-butyl hypochlorite had proved to be advantageous. In the presence of silica gel as catalyst the yield of chlorotoluenes was quantitative but the regioselectivity was more or less statistical (ref. 8). However, the use of proton-exchanged zeolite X allowed the production of chlorotoluenes with a para-selectivity of more than 90 % (Fig. 4) (ref. 9). No HCl is generated in this process since the by-product is tert-butanol, and there is no inhibition of the catalyst. Indeed, the catalyst can be reused if necessary. 

It was of interest to see if the use of tm-butyl hypobromite would provide similar opportunities for regioselectivity to those found in the case of chlorination reactions with te/t-butyl hypochlorite. The initial indications were favourable use of H zeolite X as catalyst in dichloromethane solution gave an almost quantitative yield of bromotoluenes with a para ortho ratio of 81 19 (Fig. 5) (ref. 10). 

Reactive chloramine derivatives are produced in the first reaction step as a result of chlorination of the nitrogen by the /erf-butyl hypochlorite in the presence of potassium... 

The first compound is an antibiotic isolated from Streptomyces aureus [20], while the second compound is a cytotoxic antibiotic isolated from Dysidea fragilis, a marine sponge [21]. A logical approach to the synthesis of azirines would be an elimination reaction of a suitably M-substituted aziridine. Thus, AT-chlorination of aziridine-2-carboxylic esters was carried out using ferf-butyl hypochlorite (Scheme 8). 

Chloro- and A TV-dichloro-phosphoramidate esters (20) and (21) are readily prepared from the parent phosphoramidate by direct chlorination in mildly acidic solution but when R = Ph, the use of t-butyl hypochlorite is preferable, to avoid chlorination of the aromatic nucleus. These compounds behave as pseudohalogens, (21) reacting with olefinic compounds such as styrene to give (22), which is also formed by chlorination of the N-phosphorylaziridine (23). ... 

Scheme 11.2 shows some representative halogenation reactions. Entries 1 and 2 involve Lewis acid-catalyzed chlorination. Entry 3 is an acid-catalyzed chlorination using NCS as the reagent. Entry 4 shows a high-yield chlorination of acetanilide by i-butyl hypochlorite. This seems to be an especially facile reaction, since anisole is not chlorinated under these conditions, and may involve the A-chloroamide as an intermediate. Entry 5 describes a large-scale chlorination done with NCS. The product was used for the synthesis of sulamserod, a drug candidate. 

Oxidation by chlorine to the arylimidosulfonyl chlorides is sometimes violent, and tert-butyl hypochlorite is a milder reagent. 

Rate of admission of chlorine into the alcohol during preparation of fert-butyl hypochlorite must be regulated to keep the temperature below 20°C to prevent explosion [1], A safer and simpler preparation uses hypochlorite solution in place of chlorine [2],... 

Chlorination of yohimbine (74) at the (3 position of the indole moiety with tert-butyl hypochlorite and treatment of the resulting chloride (539) with base in... 

It has been reported1 that, during the preparation of f-butyl hypochlorite according to the directions published in this series,2 an explosion occurred and caused moderate physical damage and minor injury to the operator. The cause of the accident has been attributed to lack of proper temperature control during addition of chlorine. It is strongly recommended that the reaction vessel be fitted with a thermometer that dips into the reaction mixture and that the rate of flow of chlorine be regulated so that the temperature of the reaction mixture never exceeds 20°. 

Butyl hypochlorite, warning, 44, 26 N-chlorination of amines with, 41, 82 n-Butyl isocyanide, 41,14 /er/-Butyl isocyanide, 41,14 -Butylmagnesium bromide, 41, 61 reaction with rec-butyl crotonate, 41, 61... 

Chlorinated poly(styrene) samples were prepared by chlorination of PS with CI2 in trifluoroacetic acid(9) or by free radical chlorination using f-butyl hypochlorite(lO) or by chloromethylation using chloromethyl actyl ether and SnCU(ll). 

Experiments designed to utilize spin trapping to monitor free-radical chemistry in the gas phase were first reported by Janzen and Gerlock (1969). In these, radicals generated by photolysis in a stream of carrier gas were passed over solid PBN. The PBN was then dissolved in benzene, and the solution was found to contain spin adducts of radicals present in the gas stream. Photolysis of t-butyl hypochlorite vapour in this way leads to a nitroxide whose spectrum reveals splitting from two chlorine atoms. This proved to be due to butyl nitroxide (Janzen, 1971 Janzen et al., 1970), and recalls the observation of other nitroxides which apparently result from further reaction of the initial spin adducts. 

Amino(trihalomethyl)methylenemalonates (1539) were chlorinated with chlorine in carbon tetrachloride, with /m-butyl hypochlorite in benzene, and phosphorus pentachloride or /V,/V-dichlorobenzenesulfonamide in dichloroethane (68ZOR1710 75ZOB873). Depending on the molar ratio, A-mono- or JV,./V-dichloro derivatives (1540, R2 = H, Cl) were obtained. 

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