Benzyltriethylammonium tetrathiomolybdate

Solubility soluble in CH3CN, DMF, and DMSO sparingly soluble in CH2CI2 and CHCI3. 

Form Supplied in brick red crystals, available as ammonium tetrathiomolybdate. 

Preparative Methods a solution of benzyltriethylammonium chloride (23.3 g, 102.5 mmol) in distilled water (60 ml) was added to a rapidly stirred solution of ammonium tetrathiomolybdate (13 g, 50 mmol) in distilled water (60 ml). Rapid stirring was continued for 2 h at room temperature and the solid that separated was filtered and washed with isopropyl alcohol (40 ml) and ether (40 ml). After drying under high vacuum, red crystals of benzyltriethylammonium tetrathiomolybdate (1) (24 g, 80%) were obtained in pure form 

1 furnishes the corresponding disulfides as the only products in excellent yields (eq 5). A variety of aryl diazonium fluorobo-rates react with 1 with great facility to yield the corresponding disulfides in moderate to good yields (eq 6).  

Iminium salts, generated in situ from the amides and lactams, react with 1 to produce the corresponding thioamides and thio-lactams, respectively, in good yields (eq T)P- The advantages of this methodology are the easy work-up and chemoselectively amides are thionated in the presence of ketones, aldehydes, and esters (eq 8). ra-Halo acid chlorides react with 1 and the corresponding thiolactones are obtained in moderate yields under mild reaction conditions (eq 9). This reaction works well for the synthesis of small and medium ring thiolactones, but is not useful for the synthesis of macrocyclic thiolactones.  

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Benzyltriethylammonium tetrathiomolybdate in CH3CN in 61-97% yield. Deprotection is compatible with esters such as benzyl, allyl, acetate, and -butyl esters. ... 

Benzyltriethylammonium tetrathiomolybdate, [BnNEt3]2MoS4, is a useful sulfur transfer reagent which has now been shown to effect a one-pot, three-step sequence of S-transfer— reduction—Michael addition. The intramolecular version successfully produces 1,4-oxathianes from the bromoenone 108 (Scheme 65). In like manner, the bicyclo[3.3.1]nonane skeleton incorporating a thiopyran ring can be constructed . 

The profitable conversion of thiouronium salts into dialkyl thioethers (see Section 4.1) is less successful for synthesis of diaryl thioethers. For example, l-chloro-4-nitrobenzene reacts with bis-thiouronium salts of the type (H2N)2CS(CH2) SC(NH2)2+ under soliddiquid and liquidrliquid conditions to produce the desired bis-thioethers, ArS(CH2) SAr, (20-35%), together with the diaryl sulphide, Ar2S (5-15%). Higher yields of the diaryl sulphide are observed under liquiddiquid conditions whereas, under solidiliquid conditions, the diaryl disulphide, (ArS)2, (20%) is also formed [56], Diaryl disulphides are the sole products (>65%) from the stoichiometric reaction of aryl diazonium salts with benzyltriethylammonium tetrathiomolybdate [57],... 

An interesting C-S bond formation mediated by benzyltriethylammonium tetrathiomolybdate converts -halo acid chlorides into thiolactones [64] (Scheme 4.16). 

Nitrones and amine A-oxides are deoxygenated by a stoichiometric amount of benzyltriethylammonium tetrathiomolybdate to yield imines and amines, respectively (>80%) [7]. Nitro groups and sulphoxides are not reduced under these reaction conditions. 

We therefore needed a ready synthesis of the 1,6-epithio epoxide 119. Normally, for such syntheses, the sulftir atom is introduced at an early stage [64]. However, it appeared to us that a suitable doubly-activated sugar such as 120 should be capable of direct conversion to the 1,6-epithio sugar 121 by treatment with some type of sulfur reagent. Indeed, the o-glucosyl bromide 122 was easily prepared and, upon treatment with either hydrogen sulfide and triethylamine in DMF or benzyltriethylammonium tetrathiomolybdate in chloroform, gave the... 

Keywords benzyltriethylammonium tetrathiomolybdate, alkyl halide, disulfide... 

The reaction of 3-iodopropionyl chloride with benzyltriethylammonium tetrathiomolybdate gave /3-thiolactone 77, but in rather poor yield (Equation 21) <1997T11835>. According to the authors, the poor yield resulted from the fact that 2-thietanones easily react with various nucleophilic reagents that are present in the reaction mixture and which result in cleavage of the S—C—O bond. 

Oxiranes can also be converted into thietanes. When 2-chloromethyloxirane 106a or 2-hydroxymethyloxirane 106b were treated with benzyltriethylammonium tetrathiomolybdate 3-thietanol, thietane 102 was obtained in 90% and 73% yield, respectively (Scheme 27) <2002JOC9417>. However, the reaction with 2-hydroxymethyloxirane 106b required activation with a DCC-CuCl pair (DCC = dicyclohexylcarbodiimide). 

Also, the yield of the already known dihydrodibcnzo[potassium thiocyanate, in the presence of benzyltriethylammonium tetrathiomolybdate (Equation 23) <1995JOC7142>. 

Macrocyclic diacyl and dialkyl glycerols containing a disulfide tether 191-195 have been prepared by Bhattacharya et al. (Scheme 29) <1998JOC9232>. Benzyltriethylammonium tetrathiomolybdate has been used to convert individual bis(tu-bromoacyl)glycerols to their respective macrocyclic disulfides. 

Reaction of rra r-(3-methyl-l-toluenesulfonylaziridin-2-yl)methyl toluenesulfonate 278 with benzyltriethylammonium tetrathiomolybdate gave /ra r-2-(Ar-toluenesulfonylaminomethyl)-3-methylthiirane 279 as a major product and 3-methyl-4-(toluenesulfonylamino)-l,2-dithiolane 280 as a minor product, with excellent regio- and stereocontrol (Equation 42) <2005JA12760>. A tentative mechanism for the formation of thiirane 279 and 1,2-dithiolane 280 is shown in Scheme 80. 

Two efficient syntheses have been reported for the parent 1,2,5,6-tetrathiocane (108). Treatment of 1,2-ethanethiol with TEA and carbon tetrachloride reportedly gave (108) in 85% yield <89Ml 926-01 >. Benzyltriethylammonium tetrathiomolybdate, (BnNEt3)2MoS4, a stable sulfur transfer agent, reacted with 1,2-dibromoethane to give (108) in 58% yield <94J0C1354>. 

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