Thio alcohols

Mercaptans (or thio-alcohols or thiols), the sulphur analogues of the alcohols, were formerly prepared by the interaction of an alkyl halide and sodium hydrosulphide in alcoholic solution ... 

According to method K (p. 87), one of the amino groups in 1.1-bis-diarylamino-or l.l-bis-dialkylamino-2.4.6-triphenyl-A -phosphorins can be replaced by an alkoxy group by treatment with alcohols in the presence of trifluoroacetic acid. If thio-alcohols are used, both amino groups are exchanged by alkylthio groups. Compounds of type 153 or 154 (p. 85) are also accessible to these exchange reactions. 

Phenylthio ketones are also enantioselectively hydrogenated with a BINAP-, MeO-BIPHEP (3)-, or BDPP (8)-Ru complex without any deactivation of catalyst to give the chiral thio alcohols in up to 98% e.e. [173]. The reactivity and selectivity are somewhat decreased when a y-phenylthio analogue is used as substrate, however. 

Thio-alcohol (mercaptan) Carbon di-sulphide Thionyl chloride Ammonium thio-cyanate Thio-urea... 

Sulphur Compounds.—The two preceding reactions with water and with alcohol may be carried out also with the analogous sulphur compounds, viz., hydrogen sulphide, H—SH, and thio-alcohols or mercap-tans, e.g.j C2H6—SH. The product in the first case is a thio-phenol, CeHs—SH, and in the second phenyl ethyl thio-ether, CeHs—S—C2H6. 

The relationship between the retention behavior of benzodiazepine, sulfamides, substituted anilines, barbiturates, a group of natural phenolic derivatives, diethanolamine isomers, amino acids, sulfoether, thio-alcohol, 2,4-dinitrophenylhydrazones, and their molecular connectivity indices were studied. All of the results indicate that the Rf or values are highly correlated with molecular connectivity indices. 

Vicinal phenylthio-alcohols are cleaved by lead tetra-acetate with insertion of oxygen. The 16/3-phenylthio-derivative (255) of oestrone methyl ether, for example, was reduced to the thio-alcohol (256) treatment with lead tetra-acetate then gave the cyclic hemithioacetal acetate (257), which could be methanolysed to give the derivative (258). Similar reaction after methylation at C-16 (259) gave the product (260), which was hydrolysed and cyclized (KOH-MeOH) to give the D-homo-17-en-16-one (261). ... 

The Code mentions 382 synthetic additives, comprizing 69 individual flavouring substances and the following 18 chemical groups ketones, lactones, aromatic aldehydes, aromatic alcohols, esters, ethers, isothiocyanates, indole and its derivatives, fatty acids, aliphatic aldehydes, aliphatic alcohol, aliphatic hydrogen carbide aldehydes, (translation error, probably hydrocarbons), thio alcohols, thio ethers, terpene hydrocarbons, phenols, phenolethers, furfural and its derivatives. 

Thio alcohols, in which SH and OH groups are adjacent, are subject to cyclization when treated with COClj [1075] ... 

Mercaptans may be considered as monosubstitution-products of hydrogen sulphide, C2H5.SH, just as the alcohols are considered as derivatives of water, C2H5.OH. They are sometimes called thio-alcohols. The name mercaptan was originally given to the members of this class on account of the fact that they form compounds with mercury. The name is derived from the Latin words mevcurium captans. Ethyl mercaptan is a typical... 

In the case of dibasic thio alcohols and monoethanolamines, ECF leads not only to a heterocyclic compound with hexavalent sulfur (77BCJ2809, 83SERDU204, 86NKGSH202), but also to a linear perfluoroinated compound RpSFs (86NKGSH202) (Scheme 59). 

Mechanochemical synthesis from carboxylic acids activated by CDI is applicable to 0-, S-, and C-nucleophiles. Two-step process involves CDI activation of acid 68 in the first milhng step, followed by milling with (thio)alcohol or malononitrile (Scheme 4.18). M6tro, Lamaty and coworkers obtained the corresponding esters, thioesters, and alkenol products 70 in high yields (Table 4.8) by simple treatment with water after reaction completion [12]. 

The Michael-type addition of thiols to a,p-unsaturated aldehydes has been reported to proceed very efficiently using O-TMS protected diarylprolinol 31c as catalyst (Scheme 3.32). The low configurational stability of the adducts at r.t. led the authors to modify the reaction conditions, which finally involved carrying out the reaction at -24 °C and reducing the adducts in situ, furnishing the corresponding y-thio alcohols in excellent yields and enantioselectivities. Both alkyl- and aryl-substituted enals could be used as suitable Michael... 

This route is often cited in the literature along with the Juge-Stephan method as an example of a procedure to prepare P-stereogenic phosphines via enan-tioselective synthesis. In spite of that, it has unfortunately not been applied to prepare other ligands, so its potential remains unknown. The commercial availability of ephedrine but not of the thio alcohol required to prepare 136 is a likely explanation of the lack of development of this method. 

Reactions of Formaldehyde with Mercaptans. Reactions of formalde-ifvde with thio-alcohols or mercaptans are similar in many respects to those encountered with alcohols. According to Posner ", mercaptals or methylene dithiols are formed in a two-step lection, as indicated by the equations shown below in which the R of RSH stands for an alkyl, aralkyl or aryl radical. 

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