Some Properties of the Thiomethylene Radical. Behavior With Aluminum Chloride in Benzene

Abstract

Organic sulfides and mercaptans form addition compounds with anhydrous aluminum chloride in which there is presumably a dative bond between the sulfur and the aluminum atoms, i.e., R:S:R. A1CLIt might be supposed that one effect of the addendum would be to weaken the carbon-sulfur linkage and permit reactions which involve the breaking of this bond to occur. A search of the literature, and our own experiments indicate, however, that, under mild conditions, at room temperature, this is not generally the case. Aryl sulfides, such as diphenyl sulfide, form one-to-one addition complexes with aluminum chloride which remain unchanged in benzene, even in the presence of a substantial excess of aluminum chloride.1 This is also true of primary alkyl sulfides. Normal primary amyl sulfide was recovered unchanged after heating for two hours at 80°in benzene with more than one equivalent of aluminum chloride. Ethyl mercaptan, and n-amyl mercaptan showed little activity at room temperature in similar experiments. At the boiling point of benzene some hydrogen sulfide was evolved, but little or no alkylation of the benzene took place.It is generally observed that in molecules of the type A-CH2-B, the bond between CH2 and A or B is most easily broken when both A and B are negative in nature. It was thought, therefore, that if A, in A-CH2-S-B, Aids were such a negative atom or group, the activity of the complex would be enhanced. This idea was tested using the easily available and suitable compounds: benzyl mercaptan, benzyl sulfide, and s-trithiane. It was found that all three were quite active at room temperature when in contact with benzene and aluminum chloride.

Cleavage of the Carbon-Sulfur Bond in Divalent Sulfur Compounds.

“…A reaction similar to that of equation IV-55 has been observed with aluminum chloride and dibenzyl sulfide (256). A curious transformation of dibenzyl sulfide perchlorate has been described by Hinsberg (192); the product, C2lH2oS, is…”

“…ferf-Butylbenzene in turn can be alkylated to yield p-di-ferf-butylbenzene (74 per cent yield); other catalysts (such as boron fluoride) and other aromatic compounds can be used. Benzyl mercaptan likewise alkylates benzene in the presence of aluminum chloride, yielding diphenylmethane (256). It is noteworthy that primary and secondary mercaptans do not react under these conditions (256,276).…”

“…Benzyl mercaptan likewise alkylates benzene in the presence of aluminum chloride, yielding diphenylmethane (256). It is noteworthy that primary and secondary mercaptans do not react under these conditions (256,276). Since the reaction is undoubtedly to be interpreted as an electrophilic + attack of the complex (CH3)3CSH-A1C13 or of the carbonium ion (CH3)3C on the aromatic nucleus, and since similar alkylation reactions can be carried out with primary and secondary alcohols in the presence of aluminum chloride (307), it can be concluded that the carbon-sulfur bond in primary and secondary mercaptans is not as readily cleaved in an alkylation process as the carbon-oxygen bond in alcohols.…”

A novel synthesis of 2,4,6-trithiaheptane and its conversion into 2,6-bis(methylthio)thiane. Spectral properties of some thiaalkanes

“…Such a reduction is precedented, although it does not appear to have been used widely (4). The preparation of 2a has been reported (5). We found it to be rather unstable both in solution and in the crystalline state, especially if it had not been carefully recrystallized; however, the pure solid was adequately stable if stored in a freezer.…”