Preparation of new nitrogen-bridged heterocycles. 56. Syntheses and reactions of 1-[2,2-bis(alkylthio)-1-(ethoxycarbonylacetyl)vinyl]pyridinium salts

The title compounds, readily available from the S-alkylation of pyridinium 1-[alkylthio(thiocarbonyl)](ethoxycarbonylacetyl)methylides with alkyl halides or alkyl bromoacetates, were treated with a base and then a dehydrogenating agent to provide some unique products such as 3-[bis(alkylthio)methylene]-2(3H)-indolizinones and dialkyl 7-methyl-4-oxo-1,4,8,8a-tetrahydro-1,4-thiazino[3,4,5-cd]indolizine-1,5-dicarboxylates. On the other hand, similar reaction of these pyridinium salts in the absence of the dehydrogenating agent afforded alkyl 2-hydroxyindlizine-3-carboxythiolates, whose yields were increased by adding trifluoroacetic acid to the reaction mixture. The structures of some products were confirmed by the X-ray analyses.     

Novel capto-dative (Z,E)-2-(alkylthio)alk-2-en-4-ynals: synthesis and heterocyclization

An efficient synthesis of new (Z,E)-2-(alkylthio)alk-2-en-4-ynals by aldol condensation reaction of ynals with (alkylthio)-acetaldehydes using NaOH/DMF system has been developed.The reaction of these products with N,N-diphenylethylene-diamine and p-tosylmethyl isocyanide proceeds at the carbonyl group to form the corresponding imidazolidine and oxazole derivatives.     

Synthese und Reaktionsverhalten von 3-(Bis(alkylthio)methylen)-3H-isobenzofuran-1-on-und 2-(Bis(alkylthio)methylen)-3(2H)-benzofuranon-Derivaten

Summary 3(Bis(alkylthio)methylene)-3H-isobenzofuran-1-ones2a–e and 2-(bis(alkylthio)methylene)-3(2H)-benzofuranone derivatives4a–c are obtained by reaction of phthalides1a–d or 3(2H)-benzofuranone (coumaranone3), respectively, with carbon disulfide under basic conditions followed by alkylation. The reaction behaviour of the new compounds2 and4 is investigated. 2-((2-Dimethylthio-1-oxo)ethyl)benzoic acid N,N-dimethylamide (7a) and 2-((2-dimethylthio-1-oxo)ethyl)-benzoic acid 2-methylpiperidide (7b) are surprisingly formed instead of the methylthio substitution products by treatment of2a with the corresponding amine in the presence of aluminum chloride.

Herrn Professor Dr. Dr. h. c.Waldemar Adam zum 60. Geburtstag gewidmet     

The synthesis of 2-(alkylthio)- and 2-(arylthio)-3-cyanothiophenes. The nucleophilic displacement of the alkylsulfinyl group by thiols.

The nucleophilic substitution of activated 2-(alkylsulfinyl)thiophenes with alkyl- or arylmercaptans gives the corresponding 2-(alkylthio)- or 2-(arylthio)- substituted thiophenes. When thiolate anion is used instead of thiol, sulfoxide reduction is the main reaction.     

1-(alkylthio)-polyfluoroalkynes. Reactions with mercaptans and thermal transformations

1-(Alkylthio)difluoropropynes regioselectively add dialkylamines and mercaptans with formation of 1-(alkylthio)-2-dialkylamino(alkylthio)ethenes, which exist only in the form of one (presumably the trans isomer) geometrical isomer. Thermal transformation of 1-(alkylthio)difluoropropynes occurs at a temperature of under 100°C and leads to the formation of 2,4-bis(polyfluoroalkyl)-3-(alkylthio)thiophenes. © 1998 John Wiley & Sons, Inc.Heteroatom Chem 9:151–154, 1998     

Synthesis and cofacial pi-stacked packing arrangement of 6,13-bis(alkylthio)pentacene

[reaction: see text] 6,13-Bis(alkylthio)pentacenes directed toward organic field-effect transistors (OFETs) were synthesized by the ZnI(2)-mediated reaction of trans-6,13-dihydroxy-6,13-dihydropentacene with alkylthiols, followed by the dehydrogenative aromatization of the resulting trans-6,13-bis(alkylthio)-6,13-dihydropentacenes with p-chloranil. The X-ray crystallographic analysis of 6,13-bis(methylthio)pentacene reveals that this compound is arranged as a result of cofacial pi-stacking with S-S and S-pi interactions.     

Synthesis and reactions of 2-(alkylthio)-4,4-dimenthyl-1,3-thiazole-5(4H)-thiones

Six 2-(alkylthio)-substituted 4,4-dimethyl-1,3-thiazole-5(4H)-thiones were synthesized according to a new method. The reactions of these compounds with allyl- and benzyllithium reagents, 1,3-dipoles, and dimethyl acetylenedicarboxylate proceeded in a similar manner to 2-alkyl-substituted analogues, while methyllithium reacted in a different way yielding trithio-orthoester derivatives.     

Reactions of 6-Alkoxy(alkylthio)carbonylamino-4-hydroxy-2H-pyran-2-ones with Some Electrophilic Reagents

Alkoxy(alkylthio)-4-hydroxy-2H-pyran-2-ones readily react with electrophiles to give substitution products at C³. Hard electrophilic reagents replace hydrogen both in position 3 and in position 5 of the pyran ring. Methylation of 6-alkoxy(alkylthio)-4-hydroxy-2H-pyran-2-ones with diazomethane leads to formation of O- and N-methyl derivatives.     

Mass spectra of new groups of functionalized heterocycles. 4. 1-Alkyl-2-(alkylthio)pyrroles

The electron impact-induced fragmentation of 1-alkyl-2-(alkylthio)pyrroles is accompanied by rearrangements of the molecular and fragment ions with ring expansion.     

Novel Rearrangements of 2,3-Dimercapto-1-propanol Derivatives: Formation of Dialkyl Sulfide, Dialkyl Disulfide, and 1,2,3-Tris(alkylthio)propane

The base alkylation of 2,3-dimercapto-1-propanol with alkyl halides leads in good yield to 2,3-bis(alkylthio)-1-propanol and dialkyl sulfide. The reaction of 2,3-bis(alkylthio)-1-propanol with catalytic concentrated sulfuric acid proceeds with rearrangement to give 1,2,3-tris(alkylthio)propane and dialkyl disulfide. The rearrangement reaction takes place through a common intermediate thiaranium intermediate 8.     

Thiophilic addition of alkyllithium to dithiocarboxylic acid anions:synthesis of 2-[bis(alkylthio)methylene]-1,3-dithioles

2-lithio-4,5-disubstituted-1,3-dithioles react with CS₂ in thepresence of an excess organolithium reagents yielding a product of thiophilic addition; subsequent alkylation furnished a new series of2-[bis(alkylthio)methylene]-1,3-dithioles.     

An efficient synthesis of dialkyl 2-(diphenoxyphosphoryl)-3-(alkylthio)succinates from alkylthiols, triphenyl phosphite and dialkyl acetylenedicarboxylates

An efficient synthesis of dialkyl 2-(diphenoxyphosphoryl)-3-(alkylthio)succinates, as a mixture of two diastereomers, in 78–90% yields, is described via reaction between alkylthiols, dialkyl acetylenedicarboxylates, and triphenyl phosphite. The structures of products were deduced from their high-field ¹H, ¹³C, and ³¹P NMR spectra, and IR spectral data. Since these hosphonate esters possess two stereogenic centers, two diastereomers with gauche HCCH arrangements are possible. Observation of ³ J _HH = 3.5-4.6 Hz for the vicinal methine protons confirmed the dominance of the gauche arrangement. A mechanism is proposed for the formation of products.     

Syntheses of substituted 1-methyl-2-(1,3,4-thiadiazol-2-yl)-4-nitropyrroles and 1-methyl-2-(1,3,4-oxadiazol-2-yl)-4-nitropyrroles

Starting from readily available ethyl-4-nitropyrrole-2-carboxylate ( 1 ), substituted 1-methyl-2-(1,3,4-thiadiazol-2-yl)-4-nitropyrroles and 1-methyl-2-(1,3,4-oxadiazol-2-yl)-4-nitropyrroles were prepared. The reaction of 1 with diazomethane gave ethyl 1-methyl-4-nitropyrrole-2-carboxylate ( 2 ). Reaction of compound 2 with hydrazine hydrate afforded the corresponding hydrazide 3 . The reaction of 3 with formic acid yielded 1-(1-methyl-4-nitropyrrole-2-carboxyl)-2-(formyl)hydrazine ( 7 ). Refluxing of the latter with phosphorus pentasulfide in xylene yielded compound 6 in 40% yield. Reaction of compound 7 with phosphorus pentoxide afforded compound 9 . Reaction of compound 3 with 1,1′-carboxyldiimidazole in the presence of triethylamine yielded 2-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-oxadiazoline-4(H)-5-one ( 11 ). Refluxing compound 3 with cyanogen bromide in methanol gave compound 12 . Compound 13 could be obtained through the reaction of compound 3 with carbon disulfide in basic medium. Alkylation of compound 13 afforded the correspanding alkylthio derivative 14 . Reaction of 1-methyl-4-nitropyrrole-2-carboxylic acid ( 15 ) with thiosemicarbazide and phosphorus oxychloride gave 2-amino-5-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazole ( 16 ). Sandmeyer reaction of compound 16 yielded 2-chloro-5-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazole ( 17 ). Refluxing of the latter with thiourea afforded 2-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazoline-4(H)-5-thione ( 18 ). Alkylation of compound 18 gave the corresponding alkylthio derivative 19 . Oxidation of the latter with hydrogen peroxide in acetic acid yielded 2-(1-methyl-4-nitro-2-pyrrolyl)-5-methylsulfonyl-1,3,4-thiadiazole ( 20 ).     

Heteroatomic derivatives of aziridine. 15. Reaction of 1-(triethylsilyl)- and 1-[2-(trialkylsilyl)ethyl]-aziridines with thiols

The reaction of 1-(triethylsilyl)aziridine with alkanethiols proceeds with splitting out of aziridine and the formation of (alkylthio)triethylsilanes. The reaction of 1-(triethylsilyl)aziridine with 2-mercaptoethanol leads to 2-(triethylsilyloxy)ethanethiol; the same reaction in a closed system leads to [2-(2-aminoethylthiol)ethoxy]triethylsilane. 1-[2-(Trialkylsilyl)ethyl]aziridines react with 2-mercaptoethanol and with mercapto carboyxlic acids with opening of the aziridine ring.See [1] for Communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 891–893, July, 1988.     

alpha,alpha-gem-Difluorination of alpha-(alkylthio)acetophenone derivatives with N-fluoropyridinium salts

The alpha,alpha-gem-difluorination of 2',4'-difluoro-alpha-(methylthio)acetophenone (1a) with N-fluoropyridinium salts gave 2',4',alpha,alpha-tetrafluoro-alpha-(methylthio)acetophenone (3a). This reaction was accelerated by the addition of zinc chloride, zinc bromide or anhydrous iron(III) chloride, and higher yields than the reaction without additives were obtained. The gem-difluorination reaction using FP-T300 in the presence of zinc bromide was applicable to other alpha-(alkylthio)acetophenone derivatives (1).     

Utilization of CS2 as a source of C1 synthetic units for the preparation of bis(alkylthio)methanes and alkyl dithioformates

Double insertion of CS2 into two Ru-H bonds of [(dppm)2Ru(H)2] (dppm = Ph2PCH2PPh2) affords the methanedithiolate complex [(dppm)2Ru(eta2-S2CH2)]. The methanedithiolate moiety has been functionalized using 2 equiv of RX resulting in bis(alkylthio)methane derivatives [(dppm)2Ru(RSCH2SR)][X]2. The bis(alkylthio)methane complex loses the bis(alkylthio)methane moiety under very mild conditions and in turn affords the [(dppm)2RuX2] complex from which the starting dihydride [(dppm)2Ru(H)2] has been regenerated via reaction with KOH/EtOH. On the other hand, insertion of CS2 into one Ru-H bond of [(dppe)2Ru(H)2] (dppe = Ph2PCH2CH2PPh2) followed by functionalization using RX results in alkyl dithioformate complex trans-[(dppe)2Ru(H)(SC(SR)H)][X]. In this case also, the alkyl dithioformate moiety gets eliminated under very mild conditions to afford the [(dppe)2Ru(H)(X)] derivative from which the starting dihydride has been regenerated via reaction with NaBH4. The reactions presented here constitute utilization of CS2 as a C1 synthetic source for the generation of useful organic compounds.     

Synthese von 3,3-Bis(alkylthio)-2-(2-thioxo-benzo-2H-1,3-thiazol-3-yl)-acrylsäure-Derivaten und Kristallstruktur des entsprechenden Ethyl 3,3-Bis(methylthio)acrylats

Summary The 3,3-bis(alkylthio)-2-(2-thioxo-benzo-2H-1,3-thiazole-3-yl)acrylonitriles3a–e, the methyl and ethyl acrylates4 and5a–d, respectively, are prepared by dithiocarboxylation of the corresponding derivatives of acetic acid1a–c. The crystal structure of ethyl 3,3-bis(methylthio)-2-(2-thioxo-benzo-2H-1,3-thiazole-3-yl)acrylate5a has been determined by X-ray analysis.

     

Tetrakis(alkylthio)thieno[3,4-c]thiophene: Synthesis,stability, and reactivity

The synthesis of tetrakis(alkylthio)thieno[3,4-c]thiophenes la-e by the dimerization reaction of bis(alkylthio)cyclopropenethiones is described. The remarkable thermodynamic and kinetic stability suggests the significant electron-accepting conjugation of the alkylthio substituents to the carbanionic 1, 3, 4, and 6 carbons in the framework. The isopropylthio- and ethylthio-substituted thienothiophenes 1d and 1e undergo cycloaddition reactions with dienophiles such as N-phenylmaleimide and dimethyl acetylenedicarboxylate to give the cycloadducts in moderate yields.     

4 + 1] cycloaddition of bis(alkylthio)carbenes with vinyl isocyanates. Total synthesis of (+/-)-mesembrine

[reaction: see text] The Sceletium alkaloid mesembrine has been synthesized in 13% overall yield by a sequence featuring a [4 + 1] cycloaddition of a bis(alkylthio)carbene with a functionalized vinyl isocyanate.