Dithiole-2-thiones rearrangement

Isothiazoles are reported to yield the lactam (101) on reaction with diphenyl ketene <85BSB149>. Ethyne dicarboxylate esters add to 2,1-benzisothiazole to generate quinoline esters (102), and benzyne reacts to yield aeridine <83H(20)489, 88JCS(Pl)2l4l>. 2-Methyl-2,l-benzisothiazolin-3-thione with acetylene esters forms 2-iminobenzoquinone methides (103), which dimerize to give diazocines (104) or further react with the ethyne ester to yield diadducts (105). The initial adduct formed with phenylethyne and 2-methyl-2,l-benzisothiazolin-3-thione rearranges to produce l,2-dithiole[3,26]... 

Strained olefins add to the dithiole-thione (375) to give rearranged products thus norbornadiene affords (376). l,2-Benzodithiole-3-thione (377) and cyclo-pentene form the photoadduct (378). ... 

Thermal decomposition of ethyl azidoformate in the presence of 4-phenyl-l,2-dithiole-3-thione leads to the rare 1,2,3-dithiazine system (254) (76CJC3879). The reaction presumably involves initial attack of the nitrene at S-l, followed by a [1,2] rearrangement of the resulting ylide (Scheme 34). 

The intermolecular Diels-Alder reactions of 1,3-dithioles (163) with DMAD and DEAD produced the first 7//-thieno[2,3-c]thiopyran-7-thiones (164) and 47/-thieno [3.2-c]thiopyran-4-thiones (165), the structures of which were confirmed by X-ray diffraction. Further work on the mechanism of the cycloaddition and subsequent rearrangement is in progress (Scheme 46).191... 

Dichloro-l,2-dithiole-3-thione (1) undergoes 1,3-cycloaddition with DMAD to give the adduct (2).1 On further heating with alkynes, regiospecific cycloaddition and molecular rearrangement occur with loss of chlorine to give 7//-thieno[2,3-c]thiopyran-7-thiones (3) and 4//-thieno[3,2-c]thiopyran-4-thiones (4). 

Photochemical rearrangement of some mesoionic 1,3-dithioles (160) and (161) produces the dithioles (162) and (163) (80CA(92)19766l), and 4,5-dimercapto-l,3-dithiole-3-thione (164) salts are reported to rearrange to 4,5-dimercapto-l,2-dithiole-3-thione (165) salts (77EGP124044). 

The starting material, which can also be considered as an a- (1,3 - dithiol-3 -ylidene) thioketone, is obtained by reacting alkynes with l,2-dithiole-3-thiones. These compounds when heated with elemental sulfur or sulfur-containing catalysts rearrange to l,6,6aA -trithiapentalenes as shown in equation (21). A mechanism has been suggested for this reaction (72CC540) but it should be noted that in the reaction of alkynes on l,2-dithiole-3-thiones or on 1,2,4-dithiazole-3 -thiones the final l,6,6aA 4- trithiapentalene is often obtained directly <7lAHC(l3)l6l,P. 191,199). 

Dithioles 480 undergo cycloaddition with alkynes, and subsequent rearrangement with loss of CI2 gives IH-thieno[2,3-f]thiopyran-7-thiones 481 and 4//-thieno[3,2-f]thiopyran-4-thiones 482 as an isomeric mixture (Scheme 80) <20050L791>. 

Amino-l,3-thiazoline-2-thiones undergo Dimroth rearrangement to give imidazole-2,5-dithiols in a reaction which does not appear to have... 

Direct irradiation of 9-dimethylsulphonium fluorenylide (141) in acetonitrile or tetrahydrofuran yields primarily the Stevens rearrangement product 9-methyl-9-(methylthio)fluorene (142), and a 1,2-shift of a sulphonic acid group is thought to be involved in the photoisomerization of the sodium salt of metanilic acid (m-aminobenzenesulphonic acid). Photoinduced rearrangement of 4,5-(ethylenedithio)-1,3-dithiole-2-thione (143) to the... 

However, 1,3-dithioles can be rearranged to 1,6,6aA4-trithiapentalenes, catalyzed by various sulfur-containing compounds, such as 1,2-dithiole-3-thiones,201 thioacetamide,202 phosphorus pentasulfide, elemental sulfur, dibenzylthiocarbamate, 2-mercaptobenzothiazole and tetramethyl thiuram-disulfide.203 (Scheme 14). This mechanism, however, cannot account for the... 

The reactions of alkynes, alkynoic esters, ynamines, and dehydrobenzene with l,2-dithiole-3-thiones (2b), and occasionally l,2-dithiol-3-imines (12c), has been extensively studied <82AHC(3i)63>. The initial products for thiones are 3-thioacylmethylene-l,3-dithioles or thiazoles (111), which can react further to form di- or tri- adducts (113) and (114) respectively. Other rearrangements can give trithiapentalenes (6). Thials, formed from reactions of 5-unsubstituted-l,2-dithiole-3-thiones, can dimerize to products (112) with loss of sulfur (Scheme 14). Similar types of reactions have been observed with l,2-dithiole-3-thiones (2b) reacting with alkenes and ketenes, especially under... 

In addition, 4,5-bis(alkylsulfanyl)-l,2-dithiole-3-thiones were obtained from a photochemically induced rearrangement of 4,5-bis(alkylsulfanyl)-l,3-dithiole-2-thiones <86KGS1568>. 

Dithioles and Related Systems. - Base-catalysed condensation of the 1,2-dithiolium salt (195) with ethylidenemalononitrile yields the dithiole (196). The action of potassium borohydride on the enamine (197) results in the rearranged thiopyranthione (199), presumably via compound (198). Deprotonation of the bisulphate (200) or heating the tosylhydrazone (201) produces the thienothiophen (202). It has been reported that the dihydrodithiolone (203) is desulphurized by hexaethylphosphoric triamide to yield the thietanone (204). 1,2-Dithiole-3-thiones (205 X = S =... 

A variety of thioketones have found applicability in the synthesis of heterocyclic compounds. Chloro-thioacetone reacted with trialkoxy-phosphines to give thiirans. Thiophens have been prepared from mono-thio-j3-diketones, j8-thioketo-esters, > and from a-thioketo-acids. a-Thioacyl-y-lactones and -thiolactones rearrange in acid alcoholic solution to give dihydrofurans and dihydrothiophens, respectively. The simultaneous action of carbon disulphide, sulphur, and triethylamine on aliphatic thioketones gave mixtures of l,2-dithiole-3-thiones and 1,3-dithiole-2-thiones. The formation of thio-ozonides (1,2,4-trithiolans) by... 

If the l,2-dithiole-3-thiones (123 R = Ph or CN) are heated with triphenyl phosphite in cyclohexylamine, the cinnamic acid thioamides (124) are obtained. In a rearrangement of the Wittig type, the carbanions of j3-methallyl- and benzyl-AW-dimethylcarbamates form a-mercapto-thioamides in the presence of HMPT (Scheme 2). ... 

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