1.2- Dithiole-3-thiones, reaction with

Structurally similar 5-chloro-l,2-dithiole-3-thiones 97 were obtained upon treatment of N-(2-phthalimidoethyl)-N-alkylisopropylamines with sulfur monochloride and DABCO and a final reaction with tiiethylamine (20030L929). The stability of thiones 97 is explained by the dipole-dipole interaction between the electron-rich l,2-dithiole-3-thione ring and electron-poor phthalimido groups (Scheme 48). 

Several workers have studied the reactions of l,2-dithiole-3-thiones and related systems with acetylenic esters. The thiones (395), for example, react with DMAD to give 2-thioacylmethylene-l,3-dithioles (396), which may arise through a concerted 1,3-dipolar addition to the S—C=S moiety. These adducts undergo further reaction with DMAD, yielding thiopyran-4-spiro-2 -(l,3-dithioles) (397) (Scheme 62). Similarly, the reaction of 5-phenyl-l,2,4-dithiazole-3-thione (398) with... 

Ethylenediaminetetraacetic acid, analogs, complexes of, 3 277 chelation by, 3 276-277 cobalt complex of, 3 281 complexes, 3 277-278 formation constant of, 3 273-274 -nickel, 3 17-18 stability of, 3 266-267 reaction with metal ions, 3 62 Ethylene dibromide, irradiation of, 5 196 4,5-Ethylenedithio-1,3-dithiole-2-thione based supramolecular complexes, 46 200-204 Ethylene glycol, 32 4... 

The base catalyzed reaction of 4-phenyl-l,2-dithiole-3-thione 506 with a,P-unsaturated nitriles affords 6-aminothiopyran-2-thiones. A complex mechanism is postulated for the transformation with elimination of a thioketone from a dithiepin featuring in the key step (Scheme 189) <2003PS(178)2255>. 

An unusual synthesis of 2-alkylthio-TA 41 consists in the ring enlargement of l,2-dithiole-3-thiones 40 in the reaction with sodium cyanide, followed by methylation (88JHC1223) (Scheme 9). The suggested mechanism is confirmed by an increase in yield of TA 41, when excess thiocyanate ion is added. 

Thiopyran-4-thiones give adducts with mercury dichloride which, by reaction with aqueous sodium carbonate, give a mixture of a-(l,2-dithiol-3-ylidene)ketone and thiopyran-4-one (Eq. 2).9> 10... 

A better synthesis of a-(l,2-dithiol-3-ylidene)ketones from thio-pyran-4-thiones consists in the reaction with sodium hydroxide in dimethylformamide (DMF), followed by ferricyanide oxidation (Eq. 3).11... 

Aryl-l,2,4-dithiazole-3-thiones react with phenylacetylene giving two compounds, namely, A-(4-aryl-l,3-dithiol-2-ylidene) thiobenz-amide (52) and 2,5-diaryl- 1,6,6a IV-trithia-3-azapentalene, which may also be considered as AT-(5-aryl-l -dithiohS-ylideneJthiobenz-amide (53). This compound is converted into the corresponding benzamide (54) by mercuric acetate oxidation, the opposite reaction being realized with phosphorus pentasulfide.79... 

Dithiole-3-thione, methylation of, 391 Di-(trimethyisilyl) amine, reaction with A-4-thiazoline-2-thione, 396 Diuretic sulfonamide, 414 Diuretic properties, 150, 152 Dithiobiuret, 85... 

Recently it has been reported that a-thio derivatives of enamines and enol ethers form 5-amino- or 5-alkoxy-l,2-dithiole-3-thiones (127a, b) by reaction with carbon disulfide (80ZOR13). Spiran compounds (128) are also formed from suitable substrates. The reaction has some similarities to an enamine synthesis below <67AG(E)294). 

On the other hand, reaction of the l,3-dithiole-2-thione (21) with peracetic acid in acetone at -40 °C produces the parent 1,3-dithiolylium ion (1) (74JOC2456). 

A ring transformation takes place in the reaction of 3-mercapto- or 3-acylthio-3-isothiazo-line-5-thiones (331) with reactive alkynic compounds in boiling acetonitrile this reaction produces the 1,3-dithiole derivatives (332) in good yields (80JCS(P1)2693, 80H(14)785). 

Similarly, reaction of 3-chloroacylthio-3-isothiazoline-5-thiones (333) with reactive alkynic compounds proceeds with formation of the 1,3-dithiole derivatives (334) which contain thiazolone or 5,6-dihydro-l,3-thiazin-4-one rings (81H(16)595). 

In contrast to the reaction of l,3-dithiole-2-thiones 406 (R = H or Ph) with pyrrolidi-nocyclohexene, which leads to thiophenes (see equation 23), the analogous reaction with the more reactive pyrrolidinocyclopentene results in l,3-dithionin-2-thiones 409. It is thought that the initial betaine 407 adds a second molecule of the enamine to give 408. Cyclization, followed by elimination of pyrrolidine, yields the product (equation 168)44. 

Until a few years ago, however, the cations 1 and 2 had aroused little interest. In 1947 Liittringhaus and Bottcher2 recognized the products of the reaction of l,2-dithiole-3-thiones ( trithiones ) with alkyl esters of inorganic acids as 3-alkylmercapto derivatives of the 1,2-dithiolium system these authors explained certain apparently unusual physical and chemical properties of these salts by resonance stabilization of the 1,2-dithiolium system.8 Thus these trithionium salts were the first derivatives of the 1,2-dithiolium ion to be identified with certainty. 

Both simple and hetero-fused 3Ff-l,2-dithiole-3-thiones yield 1,3-dithiin Cr complexes on reaction with Fischer carbene complexes. Treatment with methanol releases the free dithiin dithioortho esters (Scheme 52) <06JOC808>. 

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