Sulfides aryl, from amines

In 1978 and 1980 the coupling of aryl bromides and iodides with both aliphatic and aromatic thiols was first reported in the presence of NaO-t-Bu and Pd(PPh3)4 (Equation (35)).118,119 In contrast to aryl halide aminations and etherifications, the thiation reactions did not require unusual catalysts. Yet, reactions that form aryl alkyl sulfides from alkyl thiols occurred in modest yields in many cases ... 

Dialkylaminomethyl alkyl (and aryl) sulfides result from the treatment of a-halogeno-amines with mercaptans (thiophenols).325 Dehydrogenation of amino-alcohols with mercuric acetate182,328 is accompanied by the intramolecular nucleophilic addition of the alkoxyl group when formation of a five- or six-membered ring is possible, e.g. ... 

Abbott and coworkers229 found that nucleophilic addition of amines to a, p-unsaturated sulfoxide gave asymmetrically induced adducts. For example, treatment of (R)-(—)-cis-propenyl p-tolyl sulfoxide 184 with piperidine in methanol gave a quantitative mixture of the diastereomeric adduct 185. Reduction of this mixture gave (Rs)-(Sc)-2-piperidinopropyl p-tolyl sulfide 186 in 74% optical yield, suggesting that the amines attack from the opposite side of the bulky aryl group at the transition state, as shown above (Figure 6). 

Asinger s studies demonstrated that product formation is sensitive to the ratio of sulfur to ketone (1), the structure of the ketone, the replacement of ammonia by amines, the temperature and the medium. Room temperature (20-25 °C) reactions in which the ratio of sulfur to ketones is 0.5 favors the formation of 3-thiazoline, 2, as shown in Figure 1. The formation of 5-alkylidene-3-thiazolines, 3, sometimes competes with the formation of 3-thiazolines such is the case when aryl ketones such as l-phenylpropan-2-one and l-phenylbutan-2-one are employed (4). Also the additional presence of hydrogen sulfide promotes the generation of 1,2,4-trithiolanes and 1,2,4,5-tetrathiolanes from ketones ana aldehydes at the expense of 3-thiazoline formation (11-12). Increasing the S/ketone ratio to 8 favors the formation of the 3-imidazoline-5-thione (5), a product which has a greater tendency to result from aryl methyl ketones (3). 

Salts of dithiocarbamic acid can be prepared by the addition of primary or secondary amines to carbon disulfide." This reaction is similar to 16-10. Hydrogen sulfide can be eliminated from the product, directly or indirectly, to give isothiocyanates (RNCS). Isothiocyanates can be obtained directly by the reaction of primary amines and CS2 in pyridine in the presence of dicyclohexylcarbodiimide. Aniline derivatives react with CS2 and NaOH, and then ethyl chloroformate to give the aryl isothiocyanate." In the presence of diphenyl phosphite and pyridine, primary amines add to CO2 and to CS2 to give, respectively, symmetrically substituted ureas... 

Important sulfur dyes are made by treating aryl amines with sodium polysulfides, or by heating the amines with sulfur, followed by treatment with sodium sulfide. Certain sulfur blacks are made from anilines that include p-aminophenol and p-phenylenediamine (22). Derivatives of diphenylamine (8) yield blue shades. Meta-diamines, such as m-phenylenediamine (52a), give brown and yellow colorants. Sulfur dyes are inexpensive, but lack brilliance. There are no red members of this class. They are applied by means of reduction and oxidation processes. 

According to Teppema and Sebrell [357], the preparation of benzo-thiazoline-2-thiones from aryl amines, sulfur and carbon disulfide is not generally applicable. This has been confirmed by several other authors. Another synthesis, method C, has been worked out starting with o-nitro chloro benzenes. On warming these products in a solution of sodium hydrogen sulfide with slow addition of hydrogen sulfide in the presence of carbon disulfide, near 90% yields of benzothiazoline-2-thiones are obtained. 

Removal of an amino group with formation of a C-S bond cannot be achieved directly it is effected by way of the diazonium salts that are readily obtained from aromatic amines. Nevertheless, to overcome the always present, great or slight, tendency for formation of organic sulfides — as in analogous alkylations — it is customary here, too, to use as aryl acceptors only those... 

Although thiols are generally stronger nucleophiles than alcohols and amines, the sensitivity of sulfides towards oxidation as well as the formation of disulfide made the cross-coupling between aryl halides and thiols difficult. From all previously reported results, it was foimd that only aryl iodides were suitable for this copper-catalyzed coupling process. 

The synthetic route to iV-aryl [3.2.2] cryptands 5a and 5b is shown in the Scheme. Starting from the A-aryl diethanolamine, reaction with two equivalents of chloro-acetic and /-BuOK in t-BuOH followed by conversion of the diacid to the diester for purification gave la and lb in yields of 49 and 25%, respectively. Subsequent acid-catalyzed hydrolysis produced the dicarboxylic acid amine hydrochlorides 2a and 2b quantitatively. Attempts to form the diacid chloride of 2a resulted in an unreactive deep blue-colored substance of unknown identity. Ring closure was effected by adaptation of a method from peptide synthesis [8]. Mixed anhydrides 3a and 3b formed by reaction with two equivalents of isobutyl chloroformate in the presence of triethylamine were cyclized with l,10-diaza-18-crown-6 in toluene to produce the corresponding cryptand diamides 4a and 4b in 36 and 32% yields, respectively. Reduction with borane-dimethyl sulfide in THF provided 74% yields of 5a and 5b. 

Other Applications. Thionyl chloride has been used to convert epoxides to vicinal dichlorides and for the preparation of dialkyl sulfides from Grignard reagents. Phenols react with SOCI2 to produce aryl chlorosulfites and diaryl sulfites or nuclear substitution products. As shown in eq 14, Aluminum Chloride catalysis yields symmetric sulfoxides, while in the absence of Lewis acids, aromatic thiosulfonates are the principal products. Primary amines, especially aromatic ones, react with SOCI2 to produce N-sulfiny lamines, which are potent enophiles and useful precursors to some heterocyclic compounds. ... 

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