Dithiocarboxylic reactions

Similar reaction of dithiocarboxylic acids 75 with 2,4,6-trinitrochlorobenzene (76) in ethanol at 0°C yields thioesters 77, which are then cyclized at room temperature to the final product 78 (77JCS(P1)1273). 2-Oxo- and 2-iminocy-clopentane derivatives 79 provided compounds 80a and 80b, respectively (Scheme 13) (73JCS(P1)1009, 75JCS(P1)1277). 

Julia and coworkers have utilized the sulphenylation reaction in the synthesis of / , y-unsaturated dithiocarboxylates 494, via the reaction sequence shown in equation 298557. 

The chemistry of the dithiocarboxylate complexes of nickel (II) has been investigated extensively. Interest in recent years has been mainly in the further investigation of the "sulfur-rich species, the perthiocarboxylates, and the unusual structures discovered in the dithiocarboxylate complexes (359). The violet complex formed by reaction of [Ni(C H5CS2)2] with sulfur or polysulfide, [Ni(CgHsCS2)2]2, origi-... 

The degradation of CCl4 by Pseudomonas sp. strain KC involved formation of intermediate COCI2 that was trapped as a HEPES complex, and by reaction with cysteine (Lewis and Crawford 1995). Further details of the pathway that is mediated by the metabolite pyridine-dithiocarboxylic acid have been elucidated (Lewis et al. 2001). 

The degradation of tetrachloromethane by a strain of Pseudomonas sp. presents a number of exceptional features. Although was a major product from the metabolism of CCI4, a substantial part of the label was retained in nonvolatile water-soluble residues (Lewis and Crawford 1995). The nature of these was revealed by the isolation of adducts with cysteine and A,A -dimethylethylenediamine, when the intermediates that are formally equivalent to COClj and CSClj were trapped—presumably formed by reaction of the substrate with water and a thiol, respectively. Further examination of this strain classified as Pseudomonas stutzeri strain KC has illuminated novel details of the mechanism. The metabolite pyridine-2,6-dithiocarboxylic acid (Lee et al. 1999) plays a key role in the degradation. Its copper complex produces trichloromethyl and thiyl radicals, and thence the formation of CO2, CS2, and COS (Figure 7.64) (Lewis et al. 2001). 

The free dithiocarboxylic acids can be isolated, but their salts are preferred. In some cases their metal complexes can be prepared directly by insertion of carbon disulfide into metal-carbon bonds. Thus, the reaction of Grignard reagents, RMgX, with CS2, followed by acid treatment gives the dithiocarboxylic acids RCSSH and metal complexes in good yields.311... 

Thioacylsulfanylarsines (RCS2)AsPh2 were synthesized by treating piperidinium dithiocarboxylates with Ph2AsCl.189 The reaction of a -diphenylarsanyl selenoester with piperidine gave diphenylselenoarsinous and diphenyldiselenoarsinic acid piperidinium salts (Scheme 14).190... 

Thioacylsulfanylarsines (RCS2)2AsPh were synthesized by treating piperidinium dithiocarboxylates with PhAsCl2.189 Reactions of PhSbCl2 with dithiolato ligands gave dithiolene derivatives (Scheme 17).221... 

Thione-S-oxides react regiospecifically with allyl and benzylsilanes in the presence of a stoichiometric amount of tetra-n-butylammonium fluoride to produce allyl and benzyl sulphoxides [8], cf. the analogous fluoride initiated reaction of thio-ketones and dithiocarboxylic esters with silanes [9, 10]. The yields of sulphoxides... 

The TMSCN addition on aldehydes has been reported to be catalyzed by the ionic liquid [omim][PFJ [202]. The influence of the counter anion in activating the TMSCN cannot be neglected, since the TMSCN addition on aldehydes can be also catalyzed by a Lewis base. The imidazolinium-dithiocarboxylate 72 has been recently shown to catalyze the reaction also in good yields up to 99% (Scheme 80) [203]. One could assume, that the zwitterion incorporates a Lewis acid and Lewis base center. The reaction did not proceed in the absence of the catalyst. 

Amongst the important chemical conversions of macromolecular substances are the various reactions of cellulose. The three hydroxy groups per CRU can be partially or completely esterified or etherified. The number of hydroxy groups acetylated per CRU are indicated by the names, i.e., cellulose triacetate, cellulose 2-acetate, etc. Another commercially important reaction of cellulose is its conversion to dithiocarboxylic acid derivatives (xanthates). Aqueous solutions of the sodium salt are known as viscose they are spun into baths containing mineral acid, thereby regenerating the cellulose in the form of an insoluble fiber known as viscose rayon. 

The reaction between [MoCl4(NCPr)2] and dithiocarboxylic acids is a general route to the preparation of eight-coordinate [Mo(S2CR)4] complexes.168 The crystal structure of [Mo(S2CPh)4] reveals these compounds to be isostructural with the dithiocarbamates, with a dodecahedral coordination around the molybdenum and average Mo—S distances of 2.475(1) and 2.543(1) A to the two different sulfur sites.170 Cyclic voltammetry has shown that in [Mo(acda)4] (Hacda = 2-aminocyclopent-l-ene-l-dithiocarboxylic acid) the Mo can be reversibly oxidized and reversibly reduced in one-electron processes.171... 

The insertion of CS2 into transition metal -carbon o bonds also has been reported (408). The complexes (LCS2)M(CO)4 (L = Ph, p-CH3Ph, Me M = Mn, Re) are obtained by the reaction of CS2 and the LM(C0)4 complexes in CS2. The structure and bonding of these new dithiocarboxylate complexes are discussed on the basis of their mass, PMR, and IR spectra (408). 

The preparation and properties of the dithiocarboxylic acids and their metal complexes have been reviewed several times.38"11 The formation of C—C bonds in the direct reaction of CS2 requires sufficiently nucleophilic carbon bases, directly or potentially accessible in the form of ambifunction-al phenoxides, organometalfic compounds, CH acidic compounds, enamines or ketimines. Carba-nions react with CS2 to give dithiocarboxylates. The preparation and purification of the adds is performed via their salts. Metal complexes are in general readily available. The bonding in these complexes is mostly of the type (27) but a bonding mode (28) is also found. Action of elemental sulfur upon heavy metal complexes of (29) aromatic dithiocarboxylic acids yields the perthio complexes (29) of these compounds. 

The addition of DMAD to the isoquinolinium betaine 369 gave the interesting cycloadduct 370.397 A 1,4-cycloaddition and Diels-Alder reaction took place when 4-dithiocarboxyl-2,3-dimethylisoquinolinium betaine (371) was heated with DMAD in DMF for 20 to 30 minutes at 100°. The initial product was thought to be 372, which added a second mole of ester yielding 373.398... 

The generation of intermediate azidothiocarbonyl compounds 10 followed by 1,5-electrocyclic reaction leads to 5-substituted 1,2,3,4-thiatriazoles 9. This mechanism has been proposed in reactions of various derivatives of thiohy-drazides 136 with either nitrous acid or arenediazonium salts, and in reactions of thiophosgene (or dithiocarboxylates) 135 (X = C1, SR) with either sodium or trimethylsilyl azide (Scheme 32) <1984CHEC(6)579, 1996CHEC-II(4)691,... 

This method is not general and only a limited number of 5-alkyl-l,2,3,4-thiatriazoles were prepared by this reaction. Ikeda and co-workers have described a convenient method for the synthesis of both 5-alkyl- and 5-aryl-l,2,3,4-thiatriazoles 9 by reaction of l-methyl-2-thioacylpyridinium salts 143 with sodium azide (Scheme 33). Compound 143 can be prepared from pyridium salt 142 by reaction with dithiocarboxylic acid derivatives. The synthesis can conveniently be carried out as a one-pot reaction from 2-chloro-l-pyridinium salt 142 and carbodithioate leading to final compounds 9 in high yields. The 5-alkyl-l,2,3,4-thiatriazoles 9 were isolated as oils <1990S415, 1990ZC67>. 

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