Alkylthio compounds

Hydroxy and mercapto substituents at the 3- and 5-positions can also exist in tautomeric forms (see Section 4.01.5.2) and can be alkylated at either the substituent or the ring nitrogen atom. 3-Methoxy groups are not replaced by nucleophiles, but both 3- and 5-alkylthio groups react readily, as does 3-methoxy-l,2-benzisothiazole. Alkylthio compounds can be oxidized to sulfoxides and sulfones, and the latter readily undergo nucleophilic replacement. All the hydroxy compounds react with phosphorus pentachloride to give the chloro derivatives. 

Both 3-thioxo-l,2,4-triazin-5-ones (187) and 5-thioxo-l,2,4-triazin-3-ones (188) are first alkylated 5y alkyl iodides or dimethyl sulfate at the sulfur, and then with further reagent a second alkylation occurs at N-2, to form compounds (189) and (190) respectively. The 6-alkylthio-5-thioxo-l,2,4-triazin-3-ones (191) afford the 5,6-bis(alkylthio) compounds (192) as the dialkylated products. 3-Thioxo-l,2,4-triazine-5,6-dione (193) yields as the dialkylated product the 6-alkoxy-3-aIkylthio-l,2,4-triazin-5-one (194). 3,5-Dithioxo-l,2,4-triazine-6-carboxylates (195) are alkylated at both sulfur atoms to give 3,5-bis(alkylthio)-... 

Usually, 3- and 4-substituted thianes are prepared from the 3- and 4-oxothians by the common techniques applicable to alicyclic chemistry. Reduction affords alcohols which may be etherified or halogenated, while oximation and reduction produces the amino derivatives, which are also accessible via the halo compounds. 2-Alkoxy and 2-alkylthio compounds are made by acid catalyzed addition of alcohols and thiols to 3,4-dihydro-2H-thiopyran (75MI22502) in a reaction analogous to the use of dihydropyran for protection of alcohols as THP ethers. 

Alkylthio compounds containing metal coordinating groups inside the molecule in order to enhance the stability as well as the nucleophilicity of the organolithium derivative have been prepared [203], An example is given here, together with some other a-lithiated sulfides generated by metallation and which are illustrative of the versatility of the process. 

Reaction of thiols with aldehydes or ketones leads to formation of water and geminal bis(alkylthio) compounds, which, when derived from aldehydes, are known as mercaptals or, when derived from ketones, as mercaptols ... 

The action of trifluorobutenyl bromide (CF2=CFCH2CH2Br) on 3-phenyl-5-mercapto-l,2,4-thiadiazole and numerous analogs produces 5-(3,4,4-trifluoro-3-butenyl)thio derivatives (435), which are useful nema-tocides.344 The 5-alkylthio compound (436) is the product of the S-alkylation using l-(/ -chloro-2,4-dichlorophenetyl)imidazole.345 The formation of the monosulfide (437) from 3-isopropyl-5-mercapto-1,2,4-thiadiazole occurs under standard conditions.346... 

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