Halides disulfides

Sulfenylation of indoles can be carried out with sulfenyl halides[7], disulfides[7-9] or with A -methylthiomorpholine[10]. With disulfides the indoles are converted to lithium[8] or zinc[9] salts prior to sulfenylation. Thiophenols and iodine convert indoles to 3-(arylthio)indoles[l 1]. 

Vinyllithium [917-57-7] can be formed direcdy from vinyl chloride by means of a lithium [7439-93-2] dispersion containing 2 wt % sodium [7440-23-5] at 0—10°C. This compound is a reactive intermediate for the formation of vinyl alcohols from aldehydes, vinyl ketones from organic acids, vinyl sulfides from disulfides, and monosubstituted alkenes from organic halides. It can also be converted to vinylcopper [37616-22-1] or divinylcopper lithium [22903-99-7], which can then be used to introduce a vinyl group stereoselectively into a variety of a, P-unsaturated systems (26), or simply add a vinyl group to other a, P-unsaturated compounds to give y, 5-unsaturated compounds. Vinyllithium reagents can also be converted to secondary alcohols with trialkylb o r ane s. 

Pyrrolethiols, readily obtained from the corresponding thiocyanates by reduction or treatment with alkali, rapidly oxidize to the corresponding disulfides. They are converted into thioethers by reaction with alkyl halides in the presence of base. Both furan- and thiophene-thiols exist predominantly as such rather than in tautomeric thione forms. 

Benzisothiazoles are formed by the action of ammonia or amines on benzenesulfenyl halides bearing an o-carbonyl function (72AHC 14)43, 80MI41700). Analogous diphenyl disulfides behave similarly (77SST(4)339). Sulfinyl chlorides or phenylsulfoxides produce... 

Three substituted 5-phenyl unsymmetrical disulfides have been prepared, i, ii, and iii —compounds i and ii by reaction of a thiol with a sulfenyl halide, compound iii from a thiol and an aiyl thiosulfonate (ArS02SAr). The disulfides are cleaved by reduction (NaBH4) or by treatment with excess thiol (HSCH2CH2OH). 

The disulfide is dissolved by aqueous potassium hydroxide, yielding a greenish-yellow solution. At low temperatures no perceptible evolution of gas takes place. Since the disulfide in many respects behaves as a pseudo-halogen, Brown et al. have supposed that the reaction described by Eq. (8) takes place, i.e. a reaction analogous to the formation of halide and halite ions from a halogen and alkali. 

The same diamine, when treated with carbon disulfide in alkaline medium, yielded 2-mercapto- l//-imidazo[4,5-/]quinoline (88PS267,88SC973,86IJC264), which, on treatment with alkyl, aralkyl, and acid halides, gave the corresponding thioethers and thioesters 111, respectively (88PS267, 86IJC264). 

Thiols, the sulfur analogs of alcohols, are usually prepared by Sjv 2 reaction of an alkyl halide with thiourea. Mild oxidation of a thiol yields a disulfide, and mild reduction of a disulfide gives back the thiol. Sulfides, the sulfur analogs of ethers, are prepared by an Sk2 reaction between a thiolate anion and a primary or secondary alkyl halide. Sulfides are much more nucleophilic than ethers and can be oxidized to sulfoxides and to sulfones. Sulfides can also be alkylated by reaction with a primary alkyl halide to yield sulfonium ions. 

Thiol (s), 652, 667-668 disulfides from, 668 electrostatic potential map of, 75 from alkyl halides, 667 hybridization of, 20 naming, 667 odor of, 667 oxidation of, 668 pKa of, 604... 

It forms azeotropic mixts with methylol, carbon disulfide, isopentane, isopropyl halides, isoprene, etc. Prepn is by treating isopropyl ale with nitrosyl chloride. Also, by passing N02 into isopropyl ale at 25—30°. Coml prepn is similar to that of n-propyl nitrite (above). The nitrite has a flash p of < 10°... 

The stannylenes from either source will insert into the Sn- Sn, Sn-R, or Sn-H bonds of organotin compounds, and react with alkyl halides, disulfides, or peroxides as shown in the reaction scheme below, but only the stannylenes that are generated photolytically will react with carbonyl compounds, and it appears that the stannylenes may exist in two forms, perhaps related as singlet and triplet, or a com-plexed and uncomplexed species. 

Although the oxidation of thiols with chlorine or bromine in the presence of water gives sulfonyl halides or sulfonic acids, the reaction of thiols with a stoichiometric amount of BTMA Br3 and sodium hydroxide in dichloromethane-water at room temperature gives disulfides in good yields (Fig. 29) (ref. 37). 

Disulfides can be prepared by treatment of alkyl halides with disulfide ions and also indirectly by the reaction of Bunte salts (see 10-41) with acid solutions of iodide, thiocyanate ion, or thiourea, or by pyrolysis or treatment with hydrogen peroxide. Alkyl halides also give disulfides when refluxed with sulfur and NaOH, and with piperidinium tetrathiotungstate or piperidinium tetrathiomolybdate. ... 

Primary and secondary but not tertiary alkyl halides are easily converted to Bunte salts (RSSOj ) by treatment with thiosulfate ion. ° Bunte salts can be hydrolyzed with acids to give the corresponding thiols or converted to disulfides, tetrasulfides,... 

The addition of alcohols to carbon disulfide in the presence of a base produces xanthates. The base is often OH, but in some cases better results can be obtained by using methylsulfinyl carbanion (MeSOCH ) If an alkyl halide RX is present, the xanthate ester ROCSSR can be produced directly. In a similar manner, alkoxide ions add to CO2 to give carbonate ester salts ROCOO. ... 

In a KI matrix the electronic absorption maximum of 82 - is observed at 400 nm, and the 88 stretching vibration by a Raman line at 594 cm k 83 shows a Raman line at 546 cm and an infrared absorption at 585 cm which were assigned to the symmetric and antisymmetric stretching vibrations, respectively. The bromides and iodides of Na, K, and Rb have also been used to trap 82 - but the wavenumbers of the 88 stretching vibration differ by as much as 18 cm- from the value in KI. The anion S3- has been trapped in the chlorides, bromides and iodides of Na, K, and Rb [120]. While the disulfide monoanion usually occupies a single anion vacancy [116, 122], the trisulfide radical anion prefers a trivacancy (one cation and two halide anions missing) [119]. 

Analogously, sulfonyl halides such as benzenesulfonyl chloride 1764 are reduced by excess TIS 17 to disulfides such as diphenyl sulfide 1765 [22, 23] (Scheme 12.5). 

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