1.2- Dithio-3-thione

From the reactions of sulfur and carbon disulfide with cyclic ketone-derived enamines (570-573) 3H-l,2-dithiole-3-thiones were obtained, whereas the addition of carbon disulfide to other enamines gave a-dithio-pyrones (574), through initial dimerization of the enamine. 

B. A. Oude Alink. Water soluble l,2-dithio-3-thiones. Patent EP 415556, 1991. 

Silver(I) complexes with mixed donor S, 0-ligands have been described with 1-hydroxypyridine-2-thione (261),1437,1438 cyclo-L-methionylglycine,1439 acyclic polyethers (262),1440-1442 dithio- and trithio-oxalate,1443 or chlorosulfate.1444... 

Abstract Metal complexes including the dmit2- (1,3-dithio-2-thione-4,5-dithiolato) ligand are the only class of metal bis-dithiolenes to give rise to superconductive molecular materials. This chapter first focuses on the description of these superconductive phases. Further sections describe the association of M(dmit)2 moieties with three types of magnetic molecules, i.e., metalloceniums, radical cations, and spin crossover complexes. 

M(dmit)2 complexes (dmit = C3S52- = l,3-dithiole-2-thione-4,5-dithio-late) constitute one of the most important subclasses. The most studied metal complexes are those of group 10 (Ni, Pd, Pt), which possess a square-planar geometry see for instance the molecular structure of the monoanion [Ni(dmit)2], Figure 42.73... 

Kabachnik and co-workers have determined the pKa s of a number of dithio- and monothio-organophosphorus acids and considered the thiol-thione tautomeric equiUbria of monothiophosphoric acids. For most monothio acids the tautomeric equlibrium is shifted toward the thione form. There are slight changes in the pKa s of O, O -dialkyldithiophosphoric acids with substituent variation. Other data U4,29i) indicates that the pKavalues are rather substituent dependent, e.g., Ref. gives pKa values of -1.10 and +0.22 for HSP(S)(OC2Hs h... 

Pappalardo and co-workers studied the mass spectral characteristics of alkyl and aryl substituted 2,5-dithio-1,3,4-thiadiazoles. Selected ions in the mass spectra of SH, S-CH3, and S-aryl thiadiazoles were tabulated. The S-aryl thiadiazoles form stable cyclic ions yielding additional fragments. The fragmentation pattern is dependent on the structural characteristics of the substituents. If both tautomers—thiol and thione—are present, the molecular ion will also lose CS2. Besides the base peak, intense peaks observed in the MS spectrum are due to extensive fission of the thiadiazole ring. Some of the fragments formed are shown in Scheme 4 <820MS(17)335). 

Closely related are the syntheses from various sulfur-containing derivatives of 2-pyridylhydrazine by which it is possible to obtain the 3-thiol (or thione) 6180 or 3-methylaminotriazolopyridine (62).88 By use of dithio-carbamates instead of acylhydrazines, the iminoether synthesis gives the tetrahydrotriazolopyridine-3-thiol (or thione) 63.89-92 Cyclization of the amidine 64 gives 3-anilinotriazolopyridine (65).93... 

The effect of replacing the hetero O atom in maltol by S is a marked downfield shift of the two aromatic doublets (56.45 and 7.73 vs. 57.33 and 7.59) and this is accentuated in 3-hydroxy-2-methyl-4//-thiopyran-4-thione (dithio-maltol) 131 (57.52 and 8.16) <2006CC206>. 

Dithio compounds or related compounds form 1,2-dithiolylium salts (4) on oxidation in acidic media. Thus dithiomalonamides (60) are converted to 3,5-diamino-l,2-dithiolylium salts (8) (76JCS(D)455) and 2-thiocyanatoaryl thiones or thioamides (115) on acidification form various salts (116) possessing the benzo-l,2-dithiolylium nucleus (79TL3339). 1,3-Dithiones and functional derivatives are probably intermediates in some sulfurization reactions (Section 4.31.3.1.3) but are not usually isolated. 

Benzo-l,3-thioxin-4-thione (148) reacts with phenylhydrazine to form the dithiole hydrazone (149), which must arise by initial nucleophilic attack at the thione function (80T3309). The l,3-thiazine-2,4-dione (150) possesses a three-carbon unit with an attached sulfur atom. Thionation with phosphorus pentasulfide gives the unsubstituted l,2-dithio e-3-thione (3b) (70AjC5l>. 

When considering the synthesis of a dithiolene complex, it is essential to bear in mind that dithiolenes vary widely in their electronic properties. If one simply seeks an unsaturated chelating dithiolate, the most convenient options are benzenedithiolate and the inorganic dithiolenes 1,3-dithiole-2-thione-4,5-dithiolate (dmit2 ) and l,2-maleonitrile-l,2-dithiolate (l,2-dicyanoethene-l,2-dithio-late) (mnt2 ). Large-scale syntheses of these ligands are available. Dithiolenes... 

Indigoid compounds such as (Z)-2-(3-thioxo-2(377)-benzo[7]furanylidene)benzo[ ]furan-3(2//)-thione 40 have been searched for for a long time. It has been shown that formal syntheses of compound 40 lead to the valence isomer [l,2]dithio[4,3-7 5,6- ]bisbenzofuran 41, which in turn is in equilibrium with a bisdisulfide, the dimer [l,2,7,8]tetra-thiacyclododecino[4,3-A5,6-7 10,9- "ll,12-A"]tetrakisbenzofuran 42 (cf. Scheme 1). 

This synthesis provides easy and inexpensive access to the 4,5-dithio-l, 3-dithiole-2-thione system. By alkylation with 1,2-dibromoethane, 4,5-ethyienedithio-1,3-dithiole-2-thione, a key intermediate in the synthesis of bis(ethylenedithio)tetrathiofulvalene (BEDT-TTF) is obtained.4 5 BEDT-TTF forms... 

The treatment of vinyl anions with elemental selenium also leads to seleno-carbonyl compounds via eneselenolate anions (Eqs. 4-6). Deprotonation of l,3-selenothio-2-thione with EDA followed by the reaction with elemental selenium proceeds accompanied with the rearrangement of vinylic skeleton to form l,3-dithio-2-selone derivatives (Eq. 4) [38]. The vinyl anions from oxa-zolines and imidazoles were treated with elemental selenium to give the oxazo-line selone and imidazoline selone after the aqueous workup (Eq. 5) [39]. The reaction of vinyl magnesium halides with elemental selenium and allyl bromide gives allyl vinyl selenides that undergo a seleno-Claisen rearrangement to generate y,6-unsaturated selenoaldehydes (Eq. 6) [40]. 

In contrast to the preparations of 1,2-dithiolane derivatives described in this section, the sulfurization of /3-dithio-lactone 303 (Scheme 56) with 2 equiv of elemental sulfur provides a single example of formation of a 1,2-dithiolane-3-thione derivative 305 <2006H(68)2243>. An ionic intermediate 304 has been invoked to explain a ring enlargement via simultaneous departure of pyridine and migration of sulfur. 

A [2+3] dipolar cycloaddition of cyclopent-2-ene-thione 604 with an excess of diazomethane afforded the 1,3-dithio-lane 605 containing two spirocyclopentene moieties attached to the heterocyclic ring (Equation 81) <1997TL8707>. 

Acid hydrolysis of 1,2 5,6-di-0-isopropylidene-3,4-dithio-D-iditol was found171 to result in acetal migration, to afford the dithioacetal 3,4-S-isopropylidene-3,4-dithio-D-iditol (90). The action of phosphorus pentasulfide on 91 gives the corresponding 3-thione, which exists as the dimeric172 1,3-dithietane 92. 

Figure 3 Examples of molecular conductor building blocks. TTF, tetrathiofulvalene TSF, tetraselena-fulvalene TMTSF, tetramethyltetraselenafulvalene TCNQ, tetracyanoquinodimethane BEDT-TTF, bis-ethylene-dithio-tetrathiofulvalene EDT-TTF, ethylene-dithio-tetrathiofulvalene dmit, dimercaptoisotri-thione or 2-thioxo-l,3-dithiole-4,5-dithiolato dmise, 2-selenoxo-l,3-dithiole-4,5-dithiolato dddt, 5,6-dihydro-...

When ketones 32a react with elemental sulfur mixtures of thiophenes (33) and l,2-dithio e-3-ylidene ketones (34) are obtained.65 When R = Me (32b), the resulting product is a l,2-dithiole-3-thione. 

Anthranil amide is also readily cychzed with carbon disulfide in pyridine to l,2,3,4-tetrahydroquinazolin-4-one-2-thione (XXXVII, m.p. 282° C) 159). Using a -amino thiocarbonamide instead of a -amino carbonamide yields condensed l,2,3,4-tetrahydropyrimidine-2,4-dithio-nes. An example is the synthesis of 4,5,6,7-tetrahydro-lH-pyrazolo-[3,4-d]pyrimidine-4,6-dithione (XXXVIII m.p. >26O°C) from 4-thio-carbamoyl-5-aminopyrazole 159). 

The preparation of N-(2-thioxO /l4-1,3,4-thiadiazolin-5-yl) dithio-carbazate is similar to the condensation of thiocarbohydrazides with carbon disulfide and is discussed further in III.4a and III.4b. From the monohydrazones of thiocarbohydrazides the hydrazones of 5-hydr-azino-zl4-l,3,4-thiadiazoiine-2 thione may be obtained (see also III,4b). 

It was Sandstrom (301) who discovered that ammonium dithio-carbazate and chloroacetone yield both 3-amino-4-methyl-Zl4-thiazoline-2-thione (CCXVII, Ri=R.,=H, R2=CH3) (m.p. 94—5° C) and 5-niethyl-... 

Aminothiazoline-2-thiones are synthesized from potassium dithio-carbazate (54AK249 S7H1323) or potassium benzoyldithiocarbazate 67AG618) obtained in situ by the action of carbon disulfide on hydrazine or benzoylhydrazine. The alkylation of potassium salts by a-halogenocarbonyl compounds leads to intermediates 248 or 250, which are cyclized to the corresponding 3-aminothiazoline-2-thiones (249) and (252) in acidic medium. The product 252 was first mistakenly described as a thiadiazine (251) (57YZ771), but the structure was corrected in favor of... 

Reduction of carbon disulfide also provides a starting point for the synthesis of these compounds. For small scale preparation the electrochemical reduction of CS2 in DMF on a platinum or mercury electrode offers a way for the preparation of 4,5-dithio-l,3-dithiole-2-thione dianion (248) (together with significant amounts of potassium trithiocarbonate (249)), which upon alkylation gives access to 4,5-bis(alkylsulfanyl)-1,3-dithiole-2-thiones (252) (Scheme 51) <74J A945,74JOC511,81JOC775). How-... 

Conversion ofSCHO into RCHtCOOH [1, 1234, before references]. 1,3-Dithio-cyclohexane-2-thione (l)9 reacts quantitatively with trimethyl phosphite (N2, 55°,... 

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