Hypochlorite, t-butyl

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). 

Chiral alcohols have also been used in an asymmetric synthesis of sulphoxides based on halogenation of sulphides. Johnson and coworkers have found319 that the reaction of benzyl p-tolyl sulphide with JV-chlorobenzotriazole (NCBT) followed by addition of (—) menthol and silver tetrafluoroborate afforded diastereoisomeric menthoxysulphonium salts 267 which, upon recrystallization and hydrolysis, gave benzyl p-tolyl sulphoxide with 87% optical purity (equation 145). More recently, Oae and coworkers reported320 that optically active diaryl sulphoxides (e.e. up to 20%) were formed either by hydrolysis or thermolysis of the corresponding diaryl menthoxysulphonium salts prepared in situ from diaryl sulphides using ( —) menthol and t-butyl hypochlorite. 

The reaction of dimethyl sulphoxide with t-butyl hypochlorite initially yields trichl-oromethyl methyl sulphone but further reactions, involving C—S bond cleavage, occur on prolonged contact of the two reagents98 99. 

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). 

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). ... 

The imide nitrogen atom was also most reactive to a variety of electrophilic species (hydrogen halides, pseudohalogens, and alkyl halides) in the parent Rimidophosphazenes, R(C—NH)-N=PPh3. With t-butyl hypochlorite the /V-chloro-derivatives, R(C=NCl)-N=PPh3, were obtained. R/ -Vinyl-phenylphosphazenes have been prepared by condensation of aldehydes with active methylene compounds ... 

The reaction of sulphides 59 bearing an ethynyl or a carbomethoxy group a to sulphur with f-butyl hypochlorite in methanol or ethanol gives high yields of the corresponding a-alkoxy sulphides (60) rather than sulphoxides (equation 29). Oxidation of benzo[b]thiophene with t-butyl hypochlorite in t-butyl alcohol at 30-40° gave the corresponding 2-chloro-l-benzothiophen-l-oxide 61 in 45% yield (equation 30). 

The f-butoxy radicals thus formed then abstract hydrogen from hydrocarbons to generate hydrocarbon radicals and f-butyl alcohol. The hydrocarbon radicals in turn generate more r-butoxy radicals by attacking the t-butyl-hypochlorite ... 

Methods for indirect oxidation have also been developed. The combination of KF/ wCPBA in acetonitrile and water has been used to generate KOF CH3CN reagent, a mild and selective oxidant that reacts at 0 °C with no overoxidation [78]. This reagent functions by providing a fluorosulfonium ion intermediate, which is hydrolyzed in the presence of water to the desired sulfoxides. As a result of the indirect oxidation method, the typical stereoselectivity of mCPBA-type oxidations is not observed here. The KOFCH3CN oxidant is similar in scope and mechanism to 1-fluoropyridinium triflates, Selectfluor [302] and the more classical t-butyl hypochlorite [288]. 

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. 

An example of the diazaphosphoridine ring system has been reported.67 The NN -di-t-butyl phosphonic diamide (65), prepared conventionally, is treated with t-butyl hypochlorite to give the mono - iV-chl or o-der ivative (66), which readily loses HC1 to give 1,3,2-tri-t-butyl diazaphosphoridine 3-oxide (67), which can be isolated by sublimation. Methanolysis of (66) at 100 °C yields the phosphonic hydrazide (68). 

Chloro-17-nitroso-3/i-hydroxy-5a-androstane 213, generated from the oxime 212 of epiandrosterone and t-butyl hypochlorite, reacts with cyclohexadiene in chloroform/metha-nol at — 20 °C to yield, after two weeks, epiandrosterone and the bridged dihydrooxazine 214 in an enantiomeric excess of better than 95%108. 

More recently, the chiral o-substituted diarylsulfonium ylides 128 were obtained from menthoxysulfonium salts 129 and sodium dimethylmalonate (59). The desired sulfonium salts 129 were prepared from the corresponding sulfides and menthol in the presence of t-butyl hypochlorite and used further without isolation. 

A new variation of the chlorohydrin process uses t-butyl hypochlorite as chlorinating agent. The waste brine solution can be converted back to chlorine and caustic by a special electrolytic cell to avoid the waste of chlorine. 

This strategy has been extended to generate spiro derivatives from appropriate hydroxyalkylidene precursors (83BCJ2652). The salicylidene derivative (164) has also been similarly cyclized (84CL130I) by treatment with t-butyl hypochlorite to yield a mixture of diastereomers (Scheme 54). 

The metal-free imination, as well as the Rh and Ag catalyses, can be applied to the conversion of sulfides into sulfilimines such as 22 and 23 [24]. Unfortunately, however, double iminations leading to sulfondiimides (N-protected forms of 24) did not occur, and compounds such as 25 [27] still require the intermediacy of sulfondiimide 24. Thus, its preparation was achieved by treatment of the corresponding sulfide with a mixture of ammonia and t-butyl hypochlorite [28]. 

The benzodiazepine (236) can be chlorinated at the 1-position using sodium hypochloride or t-butyl hypochlorite, or at the 3-position using NCS. The 3-chloro derivative can also be prepared by treatment of the 3-hydroxy compound with thionyl chloride. Halogens at the 3-position can be displaced to give 3-amino derivatives. 

Chlorination can be effected by a variety of methods most of which involve free-radical mechanisms (8). In the present work, a chlorinating agent was sought that would preferentially attack the methyl group of polymethylstyrene so that a comparison with polychloromethylstyrene could be made. Both sulfuryl chloride (S02C12) and t-butyl hypochlorite (t-BuOCl) were suitable reagents for this purpose. 

CH3)2S=NAr, can be prepared with DMSO activated by t-butyl hypochlorite (7, 135-136). 

A solution of 2-aminobenzophenone (98 g, 0.50 mol) and methyl 2-(methyl-thio)propanoate (74 g, 0,50 mol) in CH2C12 (21) was cooled to — 70CC and 95% t-butyl hypochlorite (56 g, 0.5 mol) was added dropwise at such a rate that the temperature did not rise above — 65=C. One hour after the addition was complete, Et3N was added and the mixture was allowed to come to room temperature. The solution was mixed with 3 N HC1 (800 ml) and stirred for 1 h. The organic layer was separated, dried (Na2S04) and filtered. The solution was evaporated in vacuo and the residue triturated with ether. Filtration gave the 3-(methylthio)oxindole intermediate (92 g) in 62% yield. 

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