1.3- Propanedithiol reduction

However, a limitation in the use of certain thiol reagents, as for most reagents used for demercuration, can be their propensity to undergo elimination with reversion to the starting material. Sodium sulfide, for example, cannot be used in the reduction step of the mercurilactonization (Scheme 28), and the presence of a base (NaHCOs or EtsN) is necessary in the 1,3-propanedithiol reduction of mercurials. 

In 2009, Rauchfuss and coworkers succeeded in the synthesis of the Fe- i-H-Ni complex [(CO)3Fe(pdt)(p-H)Ni(dppe)]BF4 28 (pdt = 1,3-propanedithiolate, dppe = 1,2-C2H4(PPh2)2) as a model for [NiFeJ-hydrogenases (Scheme 64) [212]. The structure of 28 was characterized by X-ray crystallographic analysis. This is the first example of an Fe-Ni thiolato hydride complex. Evolution of H2 by electrochemical reduction of CF3CO2H (pXa = 12.65) was observed in the presence of the catalytic amounts of 28. 

Treatment of 70 with 1,3-propanedithiol and -Pr2NEt effected both the cleavage of the sulfonamide and the reduction of the azide to afford 71. 

An interesting linker is based on bis(4-hydroxyphenyl)disulfide 3 (Scheme 9.9). Both MPEG and the carbohydrate are linked as ethers, and for removal from MPEG, the linker s disulfide bond is reductively split by propanedithiol. The carbohydrate is freed as a glycoside of 4-hydroxyphenylmercaptan.38... 

In the anodic process of another bifunctional thiol, 1,3-propanedithiol, all three forms - a neutral molecule, its mono-, and dianion undergo oxidation. The addition of HO ions to the solution or a cathodic preelectrolysis (due to the reduction of protons), shift the equilibrium toward... 

Selective Reduction of Dts in the Presence of an Azide on Solid Phase Using Propanedithiol General Procedure 1431... 

Attempts to transesterify diorgano tellurium dialkoxides with 1,2-ethanedithiol or 1,3-propanedithiol caused formation of disulfides and reduction of the diorgano tellurium dialkoxides to diorgano telluriums1. 

Reduction of azides. Alkyi and aryi azides are reduced to primary amines by the combination of 1,3-propanedithiol and triethylamine (equation 1). The method is highly selective, and does not affect double or triple bonds, nitro, nitrile, carboxylic acid, amide, and ester groups. ... 

REDUCTION, REAGENTS Bis(triphenyl-phosphine)copper tetrahydroborate. Borane-Pyridine. Calcium-Methylamine/ ethylenediaminc. Chlorobis(cyclopenta-dienyl)tetrahydroboratozirconium(IV). Chromium(II)-Amine complexes. Copper(0)-lsonitrile complexes. 2,2-Dihydroxy-l, 1-binaphthyl-Lithium aluminum hydride. Di-iododimethylsilane. Diisobutyl-aluminum 2,6-di-/-butylphenoxide. Diisobutyl aluminum hydride. Dimethyl sulfide-Trifluoroacetic anhydride. Disodium tetracarbonylferrate. Lithium-Ammonia. Lithium-Ethylenediamine. Lithium bronze. Lithium aluminum hydride. Lithium triethylborohydride. Potassium-Graphite. 1,3-Propanedithiol. Pyridine-Sulfur trioxide complex. 

Howie, J.K., Houts, J.J., and Sawyer, D.T. 1977. Oxidation-reduction chemistry of DL-a-lipoic acid, propanedithiol, and trimethyllene disulfide in aprotic and in aqueous media. Journal of the American Chemical Society 99, 6323-6326. 

A cousin to this reduction is one using stannous chloride (a.k.a. SnCI2, a.k.a. Tin chloride) which is done exactly as the calcium one except that about 100g of SnCI2 is used in place of the Mg or Ca and the addition occurs at room temperature and the solution is stirred for one hour rather than 15 minutes. Some very good reductions that operate almost exclusively at room temperature with no pressure and give almost 100% yields are to follow. The only reason Strike did not detail these methods is that some of the chemicals involved are a little less common than Strike is used to but all are available to the public. These alternatives include acetlylacetone and triethylamine [73], propanedithiol and trieth-ylamine [74], triphenylphosphine [75], NaBH4 with phase transfer catalyst [76], H2S and pyridine [77], and palladium hydrox-ide/carbon with hydrazine [78], stannous chloride dihydrate [85],... 

Fig. 10 Select [NiM] complexes that catalyze proton reduction to evolve hydrogen, (a) NiFe(pdt) (dppe)(CO)3 for pdt= 1,3-propanedithiol and dppe= l,2-bis(diphenylphosphinoethane), (b) [Ni (xbsms)RuCp Cl] for H2Xbsms= l,2-bis(4-mercapto-3,3-dimethyl-2-thiabutyl)benzene, and (c) Ni2(MBT) for MBT = 2-meicaptobenthiazole [48-50]...

Under slightly different conditions, using 1,3-propanedithiol, acyloins and acyloin acetates lead to the formation of 1,3-dithianes where hydrogen has replaced the hydroxyl or acetoxyl groups . Hydrolysis to the ketone provides a method of converting acyloins to ketones and desulphurization allows conversion of acyloins to hydrocarbons (equation 10). Reduction of l,l-dimethyl-5-hydroxysila-4-cycloheptanone gave l,l-dimethylsila-4-cycloheptanone by this method (equation 11) . A similar reaction is believed to be involved in the action of D-proline reductase . ... 

Nitrile 13 was readily converted to aldehyde 16, via reduction with DIBAL, which was treated with 1,3-propanedithiol gave the dithiane 17 (Scheme 8). The carbanion of 17 afforded the first reagent that can give entrance to an all C-unimolecular micelle. Due to the bulky environment of this dithiane, it was rationalized that a cleaner procedure would utilize a carbanion with less steric congestion. Thus, when aldehyde 16 is reduced with sodium borohydride, alcohol 18 was isolated in excellent yield alternatively, nitrile 13 can be hydrolyzed... 

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