Halo thioethers

Slowly add the p-halo thioether solution from the addition funnel over a period of 18 h. Once the addition is complete, continue stirring for a further 2 h. Remove the DMF by distillation under reduced pressure (bath temperature 50°C, 0.2 mmHg) and swirl the residue with dichloromethane (2 x 150 mL) for 15 min. 

Vilsmaier, E., Spruegel, W. Halo thioethers. I. Reaction of thioethers with N-chlorosuccinimide. Liebigs Ann. Chem. 1971, 747,151-157. 

ADENOSINE-DERIVED 5 -a-HALO THIOETHER, SULFOXIDE, SULFONE, AND (5 -HALO)METHYLENE ANALOGUES. INHIBITION... 

The relative reactivity of a-haloacetates toward protein functionalities is sulfhydryl > imid azolyl > thioether > amine. Among halo derivatives the relative reactivity is I > Br > Cl > F, with fluorine being almost unreactive. The a-haloacetamides have the same trend of relative... 

The rates of SnI and Sn2 reactions are usually strongly enhanced when atoms with an unshared electron pair are directly attached to the reaction center, as in a-halo-methyl ethers, thioethers, or amines (Scheme 4.30). Only the halogens do not lead to an enhancement of Sn2 reactivity, but to inhibition of bimolecular substitution reactions (Scheme 4.30). In SnI reactions, however, a-halogens can both increase or reduce the rate of substitution [127]. 

Mixed anhydrides of carboxylic acids (RCO2H) and thiohydroxamic acid react with Sb(SPh)3 in the presence of O2 and water to give alcohols (ROH) via RSb(SPh)2 intermediates (Scheme 14.7) [28]. Both thioethers and sulfoxides bearing a hydrogen atoms are converted to a-fluorothioethers by treatment wifh (diefhylamino)sulfur trifluoride under Sb(.T, catalysis (Scheme 14.8) [29]. Treatment of 2-amino-6-halo nucleosides with tert-butyl nitrite in the presence of SbCls affords the 2-chloro-6-halopurine nucleosides (Scheme 14.9) [30]. 

Treatment with sodium ethoxide of thioethers 316, prepared by the reaction of l,2,5,6,7,8-hexahydro-l,6-naphthyridine-2thiones 317 with halo ketones, esters, amides or nitriles, resulted in the synthesis of thieno[2,3-Z>]-l,6-naphthyridines 318 (1993BCJ3716). 

By analogy with the cyclization of 2 -haIo-2-hydroxybenzophenone (above) [2676], 2 -halo-2-mercaptobenzophenone (formed in situ from the methyl thioether) reacts with potassamide-liquid ammonia to give 9-thioxanthenone. 

Palladium(0)-catalysed coupling of an orf/to-halophenolic ether (thioether) with a terminal alkyne (or with an alkynylboronic ester ) and ring closure promoted with an electrophile - iodine has been most often used - is an excellent method to make both benzothiophenes °° ° and benzofurans. ortfto-AIkynyl-phenols can be comparably closed with palladium catalysis in the presence of copper(II) halides to give the corresponding 3-halo-benzofurans, ° and ortfto-alkynyl pyridin-2- and -3-yl acetates likewise ring close with iodine, generating furopyridines. ... 

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