Mercaptan from alcohol

Applications of these methods to various synthetic objectives have been reported the preparation of organosilicon-containing pseudothiuronium salts [66], mercaptans from alcohols [9, 67], 2-alkylpseudothiuronium picrates for the estimation of tertiary alcohols [68, 69], and alkylsulfonyl chlorides from pseudothioureas by chlorination of pseudothiourea-HCl salts [55]. (CAUTION May cause an explosion [70].)... 

Bis(p-methoxyphenyl)-l,3,2,4-dithiadiphosphetane 2,4-disulfide Mercaptans from alcohols... 

Potassium tungstate-alumina Mercaptans from alcohols... 

Preparation of 2 4-dinitrophenyl-sulphides. Dissolve about 0-5 g. (or 0 005 mol) of the mercaptan in 10-15 ml, of rectified spirit (or in the minimum volume necessary for solution warming is permissible) and add 2 ml. of 10 per cent, sodium hydroxide solution. Mix the resulting sodium mercaptide solution with a solution of 1 g. of 2 4-dinitrochlorobenzene in 5 ml. of rectified spirit. Reaction may occur immediately with precipitation of the thioether. In any case reflux the mixture for 10 minutes on a water bath in order to ensure the completeness of the reaction. Filter the hot solution rapidly allow the solution to cool when the sulphide will crystaUise out. RecrystaUise from alcohol. 

The formation of mercaptans directly from alcohols may be applied to the preparation of a large number of mercaptans, but usually much longer reaction periods or higher temperatures and higher concentrations of hydrogen halides are required. Under such conditions the furan ring is destroyed. 

The X component of the substrate may be derived not only from amino acids but also from alcohols, ammonia, mercaptans, aniline, and p-nitro-phenol. A benzoyl or carbobenzoxy group has generally been employed as the R substituent of the synthetic substrate. Examination of the peptides produced by cleavage of various proteins has confirmed the rather indiscriminate specificity of this group of enzymes. 

Chloromercuri thiobenzoic ethyl ester is obtained from chloromercuribenzoyl chloride by dissolving it in hot benzene, and adding ethyl mercaptan in benzene solution through a dropping funnel. It crystallises from alcohol in pale yellow, microscopic, rhomboidal plates, M.pt. 142-5 to 144 o° C., soluble in ether, benzene, chloroform, or acetone. Its constitution is probably represented by... 

Four ethylthiocodides have been reported to exist. a-Ethylthiocodide results from heating bromo- or /3-chlorocodide with ethyl mercaptan and aqueous sodium hydroxide at 100° C. [2] it is isomerized to fi-ethylthiocodide on heating with alcoholic sodium ethoxide, a reaction that occurs when bromo- and /3-chlorocodide are heated with ethyl mercaptan and alcoholic sodium ethoxide [1-2]. From the latter reaotion a small quantity of a substanoe named y-othylthiocodido was... 

The properties of mercaptans and alcohols are quite different, although they appear to be similar in nature. The bond dissociation energy of the S-H bond is over 10/kcal/mol lower than the corresponding 0-H bond. The ease of free-radical hydrogen abstraction from a mercaptan supports this fact and permits these compounds to be included in preparative free-radical chemistry. The above fact, along with the different boiling points observed for the mercaptans compared to the corresponding alcohols and the differences in their acidities, helps explain why the chemistry of these two classes of compounds differs in so many ways. 

Selective reduction of keto to sec. alcohol groups with retention of disulfide groups Mercaptans from disulfides... 

Oxo compds. from alcohols. Ba(Mn04)2 added to a soln. of benzhydrol in acetonitrile, and the mixture refluxed for 1 h - benzophenone. Y 99%. Ba(Mn04)2 is a mild, stable oxidant, efficiently oxidizing prim, and sec. alcohols in aprotic media, whilst leaving double bonds unaffected sec. benzylic hydroxyl groups are oxidized more rapidly than non-benzylic hydroxy groups. F.e., also oxidation of (3-hydroxyketones, and preparation of disulfides from mercaptans, s. H. Firouzabadi et al.. Synthesis 1989, 378-80. 

Mercaptan-sodium alcohol Ketones from a-alkylthioketones s. 27,75... 

Nucleophilic substitution, e.g. the preparation of thiocyanates from lipophilic alcohols, can be facilitated by substrate hydrophilation via ammonioethanesulfonic acid esters (betylates)i . Mercaptans can be easily prepared from alcohols with inversion of configuration via thiolic esters prepared with thioacetic acid in the presence of 2-fluoro-pyridinium salts . C-Sulfenylation of / -dicarbonyl compounds with mercaptans by air oxidation in the presence of tetraethylammonium fluoride has been reported . Activated thiolic and selenolic esters can be prepared at room temperature from carboxylic acids and aryl thiocyanates or selenocyanates in the presence of tri-n-butylphosphine i. Phenylselenolactones have been obtained under very mild conditions from unsaturated acids and benzeneselenyl chloride. ... 

Dissolve a few drops of the mercaptan in 2 ml of alcohol and add an excess of 10% aqueous mercuric cyanide. Shake the mixture, cool it in ice and filter off the product. Recrystallize it from alcohol. 

Mix 0-2 g. of 3 5-dinitrobenzoyl chloride, 6 drops of the mercaptan and 1-3 drops of pyridine in a test-tube, and heat the mixture in a beaker of boiling water until fumes of hydrogen chloride cease to appear (15-30 minutes). Add a few drops of water, followed by a drop or two of pyridine to eliminate the excess of the reagent. The product sohdifies upon stirring with a glass rod. Add water, filter, and recrystalUse from dilute alcohol or dilute acetic acid. 

Apparently the alkoxy radical, R O , abstracts a hydrogen from the substrate, H, and the resulting radical, R" , is oxidized by Cu " (one-electron transfer) to form a carbonium ion that reacts with the carboxylate ion, RCO - The overall process is a chain reaction in which copper ion cycles between + 1 and +2 oxidation states. Suitable substrates include olefins, alcohols, mercaptans, ethers, dienes, sulfides, amines, amides, and various active methylene compounds (44). This reaction can also be used with tert-huty peroxycarbamates to introduce carbamoyloxy groups to these substrates (243). 

The length of the axial bond would be expected on all theories to be important. The barrier height does decline from ethane to methyl silane to methyl germane, but of course the bonded atoms are different. Unfortunately reliable values are not available for dimethyl mercury, dimethyl acetylene, and similar molecules with still longer bonds. An apparent exception is provided by methyl mercaptan and methyl alcohol. The latter, with the shorter axial bond, has the lower barrier. 

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