Synthesis and reaction of alpha-dithiolactone

Treatment of di-tert-butylthioketene S-oxide (5 a) with Lawesson reagent at room temperature resulted in the formation of 3,3-di-tert-butylthiirane-2-thione (4 a) in high yield. The oxidation of 4 a with mCPBA (mCPBA=m-chloroperbenzioc acid) gave 3,3-di-tert-butylthiirane-2-thione S-oxide (6) almost quantitatively. The reactions of 4 a with dimethyl acetylenedicarboxylate (DMAD) and benzyne afforded dimethyl 2-(2,2,4,4-tetramethylpentan-3-ylidene)-1,3-dithiole-4,5-dicarboxylate (13) and 2-(2,2,4,4-tetramethylpentan-3-ylidene)benzo[d][1,3]dithiole (15), respectively, in high yields, suggesting that 4 a is an excellent 1,3-dipole. The reaction of 4 a with ethylenebis(triphenylphosphine)platinum (16) gave dithiolato-platinum complex (22) in high yield. The structure of 22 was determined by X-ray crystallographic analysis.     

Syntheses on the basis of 2H-chromen-2-one and 2H-chromene-2-thione

4-Hydroxy-2H-chromen-2-one and 4-hydroxy-2H-chromene-2-thione reacted with allyl bromide, 1,1,3-trichloroprop-1-ene, and 1,3-dichlorobut-2-ene to give the corresponding ethers, which were oxidized to (2-oxo-2H-chromen-4-yloxy)acetic acid with potassium permanganate, and various derivatives of that acid were obtained. 3-(3,3-Dichloroprop-2-enyl)-7-hydroxy-4-methyl-2H-chromen-2-one and 3-(3,3-dichloroprop-2-enyl)-7-hydroxy-4-methyl-2H-chromene-2-thione were synthesized, and some their transformations were studied.     

3,3-Dimethyl-2,3,5,6-tetrahydroimidazo[2,1-b][1,3,4]thiazasilole and Its Derivatives with Five-Coordinate Silicon Atom

Previously unknown 3,3-dimethyl-2,3,5,6-tetrahydroimidazo[2,1-b][1,3,4]thiazasilole and its zwitterionic derivatives containing five-coordinate silicon atom, namely 7-substituted 3,3-dimethyl-2,3,5,6-tetrahydroimidazo[2,1-b][1,3,4]thiazasilol-4-ium chlorides, have been synthesized by reaction of 1,3-bis(trimethylsilyl)tetrahydroimidazole-2-thione with chloro(chloromethyl)dimethylsilane and subsequent transformations of the products.     

Reactions of thioketen s-oxides with diazo compounds : A novel synthesis of heterocyclic sulfines

Thioketen S-oxides 1 react with 2-diazopropane (2a) to give 1-pyrazoline-4-thione S-oxides 3 Addition of diazomethane to 1 yields a stable 1:1-adduct only from the S-oxide 1c. The constitution of both types of cycloadducts (3, 11) was proven by X-ray diffraction. Irradiation of 3 leads to loss of nitrogen to afford the alkylidene thiirane S-oxides 12.     

Studies on organophosphorus compounds—XLI : Formation of 3-pyrazoline-5-thione disulfides from 3,5-pyrazolidinediones. C-alkylation of 3,5-pyrazolidinediones

4-Substituted-1,2-diphenyl-3,5-pyrazolidinediones (Phenylbutazone analogous) 1a–d react with 2,4-bi-(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-difulside (Lawesson Reagent (LR) with formation of the corresponding 3,3′-dithiobis (1,2-dihydro-3H-pyrazole-5-thione)'s 2a–d. When the 4-substituent contains a sulfoxide group this is deoxygenated to the sulfide by LR at room tmeperature. 1-Phthalazinone-4-thione, 1,4-phthalazine-dithione and ethyl aminothioxoacetate have also been prepared from the corresponding carbonyl compounds. Alkylation or acylation of 2a–d yielded 3H-pyrazole-3-thione derivatives 8 and 9. Alkylation of 1 with MeI in the presence of Et₃N at room temp. yielded the C-alkylated products 10 exclusively. X-RAy crystallographic investigations of 2b and 9a are presented.     

Adamantylazoles: X. Reactions of 1,2,4-Triazole-3-thione with 1-Adamantanol in Acid Solutions

1,2,4-Triazole-3-thione reacts with 1-adamantanol in concentrated sulfuric acid to form 1-(1-adamantyl)-1,2,4-triazole-3-thione, which transforms into 1-(1-adamantyl)-3-(1-adamantyl)sulfanyl-1,2,4-triazole or is oxidized with atmospheric oxygen dissolved in sulfuric acid into 3,3′-disulfanediylbis[1-(1-adamantyl)- 1,2,4-triazole]. 3-(1-Adamantyl)sulfanyl-1,2,4-triazole was prepared by adamantylation of 1,2,4-triazole-3-thione in a mixture of phosphoric and acetic acid (weight ratio 4 : 1).     

Formation of condensed sulfur-nitrogen-containing heterocyclic compounds through transformations of allyl-2-pyridylsulfide and -sulfoxide

Allyl-2-pyridylsulfide gives upon heating in tetraline and DMF a mixture of 2-methyl-2,3-dihydrothieno[2,3-b]pyridine, dihydrothiopyrano[2,3-b]pyridine, and a mixture of sulfides and disulfides which are formed upon recombination of thiyl radicals. The S-oxide of this sulfide forms only 2-methyl-2,3-dihydrothieno[2,3-b]pyridine of cyclic compounds, which indicates a predominant 2,3- and not 3,3-sigmatropic rearrangement.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 851–853, June, 1989.     

Fused Mesoionic Heterocycles Analogues of Heptafulvene: Synthesis of 1, 3, 4-Thiadiazolo[3, 2-a]Pyridylium-2-Methylides

A number of 1, 3, 4-thiadiazolo[3, 2-a]pyridylium-2-methylides have been prepared either from 1-amino-4, 6-diphenylpyridine-2-thione and 3,3-bis(methylthio) acrylonitriles or by the reaction of the conjugate anion of active methylene compounds with 2-methylthio-1, 3, 4-thiadiazolo[3, 2-a]pyridinium cations.     

Synthesis of (2E)-2-(tetrafluoroethylidene)-3,3-bis(trifluoromethyl)-2,3-dihydrothiazolo[3,2-a]benzimidazole

The reaction of benzimidazoline-2-thione with perfluoro-2-methylpent-2-ene in the presence of triethylamine afforded (2E)-2-(tetrafluoroethylidene)-3,3-bis(trifluoromethyl)-2,3-dihydrothiazolo[3,2-a]benzimidazole whose structure was confirmed by X-ray diffraction analysis. The reaction pathways are discussed.     

Synthesis of δ-thiolactams by the aza-Diels-Alder reaction of in situ generated allenyltrimethylsilylthioketenes with imines

Allenyltrimethylsilylthioketenes, generated in situ through [3,3] sigmatropic rearrangement of trimethylsilylethynyl propargyl sulfides, underwent facile [4+2] cycloaddition with imines to afford the corresponding δ-thiolactams. The resulting 2-trimethylsilyl-4-methylenetetrahydroquinolidine-2-thione, obtained by the [4+2] cycloaddition using piperideine as a dienophile, was transformed into (±)-lupinine in six steps.     

Unusual Thermal Rearrangements of N-Cyclohexylidene-4-methyl-1-(methylthio)penta-1,3-dien-1-amine

We have observed unusual thermal rearrangements of N-cyclohexylidene-4-methyl-1-(methylthio)penta-1,3-dien-1-amine to 4,4-dimethyl-2-(methylthio)-3,3a,4,4a,5,6,7,8-octahydrobenzo[4,1]cyclobuta-[1,2-b]pyrrole and 1-cyclohexyl-5-methylpyridine-2(1H)-thione.     

Reaction of α,α-, α,α′-dihalothiones with 8-mercaptoquinolinium halides as a route to tetrahydro-1,4-thiazinoquinolinium halides

The reaction of 8-mercaptoquinolinium bromide with 1,3-dibromopropane-2-thione or 3,3-dibromobutane-2-thione in methanol gave the 2-bromomethyl-2-mercaptotetrahydro-1,4-thiazino[2,3,3,4-i,j]quinolinium and 3-bromo-2-mercapto-2,3-dimethyltetrahydro-1,4-thiazino[2,3,3,4-i,j]quinolinium bromides which readily exchanged the Br⁻ anion for ClO ₄ ⁻ upon treatment with sodium perchlorate in methanol. Oxidation of the 3-bromo-2-mercapto-2,3-dimethyltetrahydro-1,4-thiazino[2,3,3,4-i,j]-quinolinium bromide by selenium dioxide gave 2,2-dithiobis(3-bromo-2,3-dimethyltetrahydro-1,4-thiazino[2,3,3,4-i,j]quinolinium) bromide. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1720–1723, November, 2006.     

The photochemistry of cyclic nonenolizable α-diketones and ketones influence of remotely positioned sulfide,sulfone, and sulfoxide functionalities

The photochemistry of 3,3,6,6-tetramethyl-1-thiacycloheptane-4,5-dione has been examined along with that of the corresponding S-oxide and S,S-dioxide. The chief photochemical process in the first mentioned compound is ring contraction affording 3,3-dimethyl-1-thia-cyclobutan-2-one, isobutene, and carbon monoxide. In addition a small amount of 3,3,6,6-tetramethyl-1-thiacyclohexan-4-one is formed along with two isomeric unsaturated aldehydes. On independent irradiation this thiacyclohexanone affords the same products as its 7-membered diketone counterpart. Similar products are obtained for the S-dioxides investigated save that the ring contraction process was absent. The S-oxides gave no identifiable products. All the results are rationalized in terms of a generalized mechanism involving biradical intermediates.     

Investigation of the reactions of fluorinated isatins and N-acetylisatins with thiocarbohydrazide: Synthesis of a novel spiro system: 2-oxo-1′,2′,4′,5′-tetrahydrospiro[3H-indole-3,3′-1,2,4,5-tetrazine]-6′-thione

A novel system 2-oxo-1′,2′,4′,5′-tetrahydrospiro[3H-indole-3,3′-1,2,4,5-tetrazine]-6′-thione has been synthesized by the treatment of fluorinated isatins with thiocarbohydrazide in aqueous ethanolic medium. Under exactly similar conditions, N-acetylisatin gave exclusively thiocarbohydrazone. The spiro product, on treatment with acetic acid, gave fluorinated isoindigo. Characterization of these products have been done by elemental analyses, ir, pmr and mass spectral studies.     

Synthesis of 4-alkyl-2-aryl-1,3-oxazole[5,4-d]pyrimidine-7(4H)-thiones and 6-alkyl-2-aryl-1,3-oxazole[5,4-d]pyrimidin-7(6H)-ones from 2-aroylamino-3,3-dichloroacrylonitriles

The sequential treatment of accessible 2-aroylamino-3,3-dichloroacrylonitriles with excess of amine, triethyl orthoformate, and hydrogen sulfide results in 4-substituted oxazole[5,4-d]pyrimidine-7(4H)-thione. The sequential reactions of the same reagents with sodium methylate, trifluoroacetic acid, triethyl orthoformate, and amines give rise to the 6-substituted oxazole[5,4-d]pyrimidin-7(4H)-one.     

Evidence for intermolecular interaction between sulfonium and sulfide sulfur atoms and its application to synthesis of cyclic bis(disulfide) dimer

On the basis of the remote Pummerer reaction of p-bis(alkylthio)-aromatic S-oxides, the intermolecular interaction between the sulfonium and sulfide sulfur atoms is described. (1) In marked contrast to the Pummerer reaction of 1b-d(3) with (CF(3)CO)(2)O (J. Org. Chem. 1999, 64, 3190-3195), the reaction of 3,3',5,5'-tetramesityl-4-(trideuteriomethylsulfinyl)-4'-(methylthio)biphenyl (1a-d(3)) as a sterically hindered analogue of 1b gave only 2a-d(2). (2) Both reactions of the two unsymmetrical regioisomers of 1-(ethylthio)-4-(methylthio)benzene S-oxide (5a and 5b) with (CF(3)CO)(2)O afforded a mixture of the mono-Pummerer products 6a and 6b, the bis-Pummerer product 7, and the bis-sulfide 8 in a similar ratio. The quenching at the initial stage of both reactions produced 5a, 5b, 8, and the bis-sulfoxide 10 in a similar ratio. These results indicate the equilibrium in the intermolecular interaction between the sulfur atoms. (3) The reaction of the p-bis(benzylthio)-aromatic S-oxide 16 with (CF(3)SO(2))(2)O gave the cyclic bis(disulfide) dimer 17 for the diphenyl sulfide and diphenylmethane spacers or the cyclic tetrakis(disulfide) tetramer 19 for the benzene and biphenyl spacers via the debenzylation of an intermolecular dithia dication. The cyclic bis(dithia dication) dimer A resulting from the intermolecular interaction between the sulfonium and sulfide sulfur atoms is proposed as an intermediate throughout the present reactions.     

Synthesis and structure determination of isomeric 7- and 8-chloro-1,5-benzodiazepine derivatives

Reaction of 4-chloro-1,2-benzenediamine with 3,3-dimercapto-1-phenyl-2-propen-1-one afforded, as expected, a mixture of 7-chloro and 8-chloro-1,3-dihydro-4-phenyl-2H-1,5-benzodiazepine-2-thione. After separation of the two components and further reaction, their structure was established by chemical degradation of 7-chloro-2-(2-diethylaminoethylthio)-4-phenyl-3H-1,5-benzodiazepine to 5-chloro-1,3-dihydro-1-methyl-2H-benzimidazol-2-one. The structure was also confirmed by single X-ray analysis of 7-chloro-2-(2-diethylaminoethylthio)-4-phenyl-3H-1,5-benzodiazepine.     

Adamantylazoles: IX. Acid-catalyzed Adamantylation of 1,2,4-Triazol-3-thione

1,2,4-Triazole-3-thione reacts with 1-adamantanol in sulfuric acid to form 1-(1-adamantyl)-3- [(1-adamantyl)sulfanyl]-1,2,4-triazole and 3,3′-disulfandiylbis[1-(1-adamantyl)-1,2,4-triazole].__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 142–145.Original Russian Text Copyright © 2005 by Amandurdyev, Saraev, Polyakova, Golod.     

Direct,Enantioselective, and Nickel(II) Catalyzed Reactions of N-Azidoacetyl Thioimides with Trimethyl Orthoformate: A New Combined Methodology for the Rapid Synthesis of Lacosamide and Derivatives

A direct and highly enantioselective reaction of N-azidoacetyl-1,3-thiazolidine-2-thione with trimethyl orthoformate catalyzed by Tol-BINAPNiCl₂ in the presence of TESOTf and 2,6-lutidine is reported. The heterocyclic scaffold can be easily removed by addition of a wide array of amines to give the corresponding enantiomerically pure 2-azido-3,3-dimethoxypropanamides in high yields. Appropriate manipulation of the N-benzyl amide derivative provides an efficient access to the antiepileptic agent lacosamide through a new enantioselective C−C bond-forming process. DFT computational studies uncover clues for the understanding of the remarkable stereocontrol of the addition of a nickel(II) enolate to a putative oxocarbenium intermediate from trimethyl orthoformate.     

[4+2]-Cycloaddition of sterically hindered thiophene S-oxides to alkenes and SO extrusion reactions of the cycloadducts

Cycloaddition reactions of 2,5-di-tert-butylthiophene S-oxide and 2,3,4,5-tetrakis(p-tolyl)thiophene S-oxide with alkenes are described. The reactivity of 2,5-di-tert-butylthiophene S-oxide as diene in Diels–Alder reactions is compared with 2,5-di-tert-butylthiophene S,S-dioxide. The thermal and photochemical SO extrusion reactions of the cycloadducts under formation of highly substitutedaromatic compounds are exemplified.