Convenient one-pot syntheses of 1,2-dithiole-3-thiones and 3-imino-1,2-dithioles from terminal alkynes

The reaction of acetylide anions with carbon disulfide or phenyl isothiocyanate followed by addition of sulfur in the presence of a protonating agent such as a primary amine or alcohol affords 1,2-dithiole-3-thiones or 3-imino-1,2-dithioles in good to excellent yields.     

Fused 1,2-dithioles. IV. Synthesis and reactions of 1,2-dithiole s-oxides

1,2-Dithiolopyrrolones and their heterologues of type 1 are resonance stabilized systems displaying a high dipole moment. Upon oxidation with organic peracids compounds 2 , 5 , 15a, 16a, 20a and 25a gave the corresponding S(2)-oxides and, depending on substituents, in some cases the S(2)- and S(1)-dioxides. The S(2)-monoxides showed a proclivity to disproportionation and were easily reduced to dithioles with symme trical dimethylhydrazine. From S(2)-oxides and several primary amines bicyclic isothiazole-S-oxides were obtained (S/N-exchange reaction). From the N-unsubstituted isothiazole S-oxide 10e the N-hydroxyisothiazole 9d was synthesized by an aza-Pummerer-type rearrangement. The assumption is made that S(2)-oxides may be biologically important as active metabolites of pyrrothines and analogues of type 1 in their action as antibacterials and antimycobacterials.     

Thio-acids—V : Some reactions of 3-oxo-1,2-dithioles

Diphenyldiazomethane with compound (1) gave dibenzoyl, while 2 and 3 gave the corresponding 3-oxo(2H)thiophenes 5. With copper-bronze 1 gave 2,2′-di-(thiobenzoate) (4), while 2 gave 2,7-diphenylthiepin (6a) and 2,5-diphenylthiophene (7a), but 3 gave only 2,5-di-(p-methoxyphenyl)thiophene (7b). With Grignard reagents 1 gave the corresponding methanol derivative 14, while 2 gave the thiobenzoylethylenes 13a and b, but 3 gave 2,7-di-(p - methoxyphenyl) - 4,4,5,5- tetraphenyl(4H)thiepin (15). The reaction mechanisms are discussed.     

Quantum-chemical investigation of the mechanism of reaction between 1,2-dialkyldiaziridines and heterocumulenes

By quantum-chemical method in the framework of the density functional theory [B3LYP/6-31G(d)] a mechanism of reaction between 1,2-dialkyldiaziridines and ketenes CH₂=C=O, PhCH=C=O, and aroyl isocyanates was investigated. The fragment Ph-CH-C(O) in the intermediate governing the cleavage of the N-N bond of the diaziridine ring is virtually planar leading to a considerable loosening of the bond. In the intermediate governing the cleavage of the C-N bond of the ring the fragment Ph-C(O)-N?C(O) is nonplanar resulting in significantly lesser loosening of the N-N bond and in the C-N-opening of the diaziridine ring. The calculated thermodynamical parameters are well consistent with the experimental data on the reactivity.     

Fluorinated heterocumulenes

Conclusions An investigation has been carried out into the cycloaddition of alkoxy-substituted alkenes to N-phenylbis(trifluoromethyl)ketenimine, leading to the synthesis of fluorinated quinolines and azetidine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 858–862, April, 1976.For No. 12, see [1].     

Fluorinated heterocumulenes

Conclusions Cycloaddition of perfluoroisobutylene to the C=N bond of bistrifluoromethylketenimines takes place in the presence of nucleophilic catalysts.For communication 13, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, Vol.8, pp. 1813–1817, August, 1976.     

Fluoro-containing heterocumulenes

Conclusions A new method was developed for the synthesis of fluoro-containing iminoindolenines and indolenides by the 1,4-cycloaddition of isonitriles to N-arylbis(trifluoromethyl)ketenimines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.2, pp. 355–358, February, 1973.     

Fluoro-contaiming heterocumulenes

Conclusions A stydy was made of the reaction of oxygen transfer from nitrones to N-aryl-bis(trifluoromethyl)-ketenimines, which leads to the formation of oxindoles.See [l] for Communication 7.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2566–2572, November, 1973.     

The structure of 1,2-dithioles studied by 13C n.m.r. spectroscopy

The charge separation between the dithiole ring and oxygen in 3-(1′,2′-dithiole-3′-ylidene)-6-methyl-2,3-dihydropyran-2,4-diones and 3-(1′,2′-dithiole-3′-ylidene)-2,3-dihydrobenzo[b] pyran-2,4-diones has been determined by ¹³C and ¹⁹F n.m.r. spectroscopy. By both methods it is found that these compounds are relatively polar. A correlation is established between the ¹³C chemical shift of some carbon atoms and the S2p binding energies measured by e.s.c.a. in the 1,2-dithiole derivatives. This correlation shows that these ¹³C shifts depend on the positive charge taken by the 1,2-dithiole ring and can then constitute a convenient evaluation of this charge.     

Synthesis of 2-acylmethyl- and 2-acylmethylenebenzo-1,3-dithioles from α-alkynyl ketones

The reaction of -alkynyl ketones with o-phenylenedithiol, which leads to the formation of 2-acylmethylbenzo-1,3-dithioles, was investigated. Reactions of the latter with hydrazine hydrate and hydroxylamine and oxidation were realized. Difficult-to-obtain 2-acylmethylenebenzo-1,3-dithioles were obtained by the reaction of -bromoalkynyl ketones with o-phenylenedithiol. The IR and PMR spectra of the synthesized compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 329–332, March, 1981.     

Synthesis of oxoindolin-3-ylidene-1,3-dithioles

An efficient and one-pot synthesis of 2-(2-oxoindolin-3-ylidene)-1,3-dithiole-4,5-dicarboxylates by a three-component condensation reaction of isatins, carbon disulfide and dialkyl acetylendicarboxylates in the presence of Bu₃P is reported. Reaction of carbon disulfide and dialkyl acetylene dicarboxylates with acenaphthylene-1,2-dione, ninhydrine and pyrimidine-tetraone resulted in the formation of 2-(2-oxoacenaphthylen-1(2H)-ylidene)-1,3-dithiole-4,5-dicarboxylates, 2-(1,3-dioxo-1H-inden-2(3H)-ylidene)-1,3-dithiole-4,5-dicarboxylates and 2-(2,4,6-trioxotetrahydropyrimidin-5(6H)-ylidene)-1,3-dithiole-4,5-dicarboxylates, respectively, in the same conditions.