Heteroaryl Sulphides

Heteroaryl Sulphides.—Oxidation of thiols in the presence of pyrrole, using I2-KI, gives 2-pyrrolyl sulphides, via the sulphenyl iodide analogous 2-methylthio-indoles are obtained directly from the indole and MeSCl, while isatin (37) gives the thioketal (38) through the route shown, from 

Heteroaryl Sulphides.— The earlier section dealing with Preparations of Sulphides describes applications of general S3mthetic methods leading to heteroaryl sulphides, and this section deals with more specific syntheses and some properties of these compounds. 

Tejima, Chem. and Pharm. Bull. Japan), 1974, 22,1331. 

Pyridine 1-oxide reacts with adamantane-1-thiol in acetic anhydride to give 2- and 3-(l-adamantanethio)pyridines and their tetrahydropyridine analogues. Corresponding butylthio-substituted pyridines are obtained using Bu SH or Bu SH in this reaction in the presence of a chloroformic acid derivative. No complications arise in the use of 3-bromopyridine 1-oxide and KSH for the synthesis of 3,3 -dipyridyl sulphide. 2-Methyl- or 2-phenyl-pyridine is converted into its 5-alkylthio-homologue by reaction of the pyridine-MeLi adduct with a dialkyl disulphide.  

2-Phenylindole reacts with dimethyl sulphoxide to give the 3-methylthio-homologue. Bis(2- and 3-indolyl) sulphides are accessible from the indoles by reaction with SCl2.  

A novel synthesis of p-tolylthio-imidazoles involves the addition of p-tolylthio-methyl isocyanide TolSCH2N=C to a nitrile. Thermal rearrangement of 5-methylthio-imidazolines (30) to imidazoles (31) has been shown to be an intramolecular process.  

Heteroaryl Sulphides.—Syntheses based on simple inorganic sulphur reagents are commonly used, and are illustrated for imidazopyridyl sulphides, di(2-pyrrolyl) sulphides and sulphides derived from related five-membered heterocycles, and di(3-pyrrolyl) sulphides/ In the latter case, the sulphur reagent with which a 2,2, 3 -trisubstituted pyrrole is converted into the sulphide is SO2 or SCh/  

Extensive studies are being conducted on a series of methylthio-pHirines, concerned with synthesis and effects of the methylthio-substituent upx n structure and reactivity of other functions/ 6-Alkylseleno-9-0-i -ribofu-ranosyl)purines are reductively deselenized to nebularine in near-quantitative yield with Raney nickel/  

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A new route to 2-aryl and 2-heteroaryl 2,5-dihydrophosphole oxides (20) and sulphides (21) is available from arylation of the phosphole metal... 

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