2168-78-7

T3P-DMSO mediated desulfurative cyclization of in situ generated thioamides serves as an efficient and versatile method for the synthesis of imidazo[1,5-a]pyridines and [1,2,4]-triazolo[4,3-a]pyridines with good to excellent yields. Substrates such as 2-methylaminoquinoline and pyrazin-2-yl-methanamine also undergo the corresponding reactions at room temperature. This efficient protocol has several advantages such as mild conditions, short reaction time, operational simplicity and high yields.

The solvent is an important, yet often forgotten part of a reaction mechanism. Many photochemical polymerizations are carried out using dimethyl sulfoxide (DMSO) as a way to promote the solubility of both the reactants and products, but its reactivity is rarely considered when initiation mechanisms are proposed. Herein, the oxidation of DMSO by an excited-state quinone is used to form initiating radicals resulting in the polymerization of methacrylate monomers, and the polymerization can be controlled with the addition of a chain transfer agent. This process leads to the formation of polymers with narrow molecular weight distribution, and the polymerization is able to be carried out in the presence of oxygen. A visible light absorbing substituted anthraquinone is synthesized, and nanosecond transient absorption spectroscopy is used to monitor the intermediates involved in the initiation mechanism. Photoproduct analysis indicates formation of methyl radicals as a result of DMSO oxidation. Furthermore, we show that the solvent outcompetes the chain transfer agent for interacting with the excited-state anthraquinone. These observations have a broad impact on photoinduced polymerizations performed in DMSO as many photocatalysts are strong oxidants in the excited state and are capable of reacting with the solvent. Therefore, the role of the solvent needs to be more carefully considered when proposing mechanisms for photoinduced polymerizations in DMSO.

A new class of thioamide-substituted cinchona derivatives is reported. A convergent and practical approach was developed to insert the thioamide functional group onto the cinchonidine from readily available dithioesters. These organocatalysts were effective in asymmetric decarboxylative Mannich and protonation reactions of α-amido-substituted malonic acid half oxyesters (MAHOs), affording α,β- and α-amino acid derivatives, respectively, in good yields and stereoselectivities.

The reactivity of Ni(PMe3)4 with CO2, CS2 and SCNPh was studied. Although CO2 is structurally homologous compound with CS2 and SCNPh, its reactivity with Ni(PMe3)4 shows a different result with those of CS 2 and SCNPh. Reactions of Ni(PMe3)4 with carbon disulfide and phenyl isothiocyanate in THF give the tetrahedral coordinate complexes (Me3P)3Ni(η2-CS2) (1) and (Me3P)3Ni(η2-SCNPh) (3), characterized by standard spectroscopic methods and X-ray diffraction. Nickel(0) complexes 1 and 3 are stabilized by the strong donor ligand PMe3. In the case of CO2, attempts to isolate the expected nickel(0) complex (Me 3P)3Ni(η2-CO2) (4) proved to be unsuccessful. To further extend the utility of our nickel catalysts, the catalytic coupling of organozinc bearing different functionalities with CS 2 was explored. With 10 mol% of 1 as the catalyst, MeZnMe, EtZnEt and PhZnBr coupled with CS2 to form the corresponding methyl dithiocarboxylate following esterfication of the initial products.

A very efficient, high yielding procedure to synthesize substituted aromatic and heteroaromatic dithioesters is described. It involves the reaction between (phenylsulfonyl)methyl (hetero)aromatic derivatives and elemental sulfur in basic medium, followed by alkylation.

The present invention provides thiadiazolyl and oxadiazolyl phenyl oxzolidinone compounds of formula I STR1 wherein Q is thiadiazolyl or oxadiazolyl; wherein X1 and X2 are independently hydrogen, fluorine or chlorine; and wherein R1 is, for example, --COCH3 or --COCH2 CH3. These compounds are useful antimicrobial agents, effective against a number of human and veterinary pathogens, including gram-positive and gram-negative aerobic bacteria.

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With a mixture of sulfur and amine in DMF at room temperature halomethyl compounds (1,5-10) can be oxidized to give thiocarboxylic acids (2,11-16) and their derivatives (3,4,17-35).We studied this reaction in detail especially with chloroacetic derivatives (11-15) or chloromethyl heterocycles (16) formally derived from chloroacetic acid.The resulting thiooxalic acid derivatives (11-27) represent activated acids and very useful C2-synthons, especially for the synthesis of heterocycles.Oxidation in the presence of triethylamine leads to dithiocarboxylates (11-16) which can be alkylated to dithioesters (17-27) in high yields.As a rule, with different primary and secondary amines instead of tertiary amines these dithiocarboxylates or dithiocarboxylic esters can be transformed already at low temperatures to thioamides (28-35).

At high temperature (130 deg C), carboxylic acid chlorides react with O,O-dialkyldithiophosphoric acids (RO)2P(=S)(SH), Ia-c to give the corresponding dithiester RC(=S)(SR) II in varying yields, while benzoyl chloride reacts with compounds Ia, b at 20 deg C to give the corresponding S-benzoyl-O,O-dialkyldithiophosphate (RO)2P(=S) IIIa, b.Mechanistic consideration on the formation of the products are discussed.Key words: Carboxylic acid chlorides; O,O-dialkyldithiophosphoric acids, and S-benzoyl-O,O-dialkyldithiophosphates.

Esters 1 are efficiently deoxygenated to the corresponding ethers 3 in two steps by first conversion to the thionoesters 2 and subsequent reduction of these by triorganotin hydrides.

Copper(I) halides catalyse the formation of carbodithioates RCSSLi in the reaction of aryl- or heteroaryl-lithium reagents with carbon disulfide.Subsequent addition of methyl iodide gives the dithioesters RCSSCH3 in highh yields.Appreciable amounts of the methyl sulfides RSCH3 and tars are obtained when the reaction with CS2 is carried out in the absence of copper(I) salts, especially in the case of more basic organoalkali compounds.

This paper describes the synthesis and pharmacological evaluation of a number of substituted 1,3,4-thiadiazoles.The first member of the series, 2-(aminomethyl)-5-(2-biphenylyl)-1,3,4-thiadiazole (7) was found to possess potent anticonvulsant properties in rats and mice and compared favorably with the standard anticonvulsant drugs phenytoin, phenobarbital, and carbamazepine in a number of test situations.The potency of compound 7 was maintained on alkylation of the side-chain nitrogen atom; however, aryl substitution or chain lengthening caused a drop in potency.Replacement of the 2-biphenylyl group by phenyl or benzyl also lead to inactive compounds.

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2,4-Bismethylthio-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IIa, is prepared from O,O-dimethyldithiophosphoric acid, Ia, and P4S10 at 160 deg C. 2,4-Bis(4-phenoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IIc, and 2,4-bis(4-phenyl-thiolphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, IId, are prepared at 160 deg C from P4S10 and diphenylether and diphenylsulfides, respectively.Carboxylic acids RCOOH (R=CH3, C2H5, n-C3H7, n-C4H9, C6H5CH2, C6H5) react with compound Ia at 130 deg C to give the corresponding methyl dithioesters.Carboxylic acids RCOOH (R=C6H5-CH2, C6H5) react with compound Ib at 200 deg C for 15 min to give the corresponding ethyl dithioesters, while low boiling acids (R=CH3, C2H5, n-C3H7) yielded mixtures of the corresponding ethyl dithioester and ethyl carboxylate.Carboxylic acid chlorides RCOCl (R=ClCH2, C2H5, t-C4H9, C6H5CH2, C6H5, p-NO2C6H4) react with compound IIa at 80 deg C to give the corresponding methyl dithioesters in good yields.S-Substituted thioesters react with IIc at 85 deg C to give the corresponding dithioesters in good yields.Dihydro-2(3H)-furanone, VI, and 5-methyl-2(3H)-furanone, VII, react with IIa at 80 deg C to give dihydro-2(3H)-thiophenethione, VIII and 2,2'-dithiobis(5-methyl thiophene), IX, respectively.Also XI reacts with IIa, IIc, and IId to give VIII in nearly quantitative yields.

Co-electroreduction of methyl dithiobenzoate (1a) and 1,3-dimesyloxypropane (5) in acetonitrile yields the tetrahydrodithiepine 6, whereas the thiirane 9 is formed from trimethylene-1,3-bis-dithiobenzoate (7a) and methyl iodide.The bis-thioacetals 8 are obtained, if 7a and its homologue 7b are electrolized together with methyl iodide; the heterocyclic bis-thioacetal 10 is formed from 7c as a mixture of the meso- and d,l-diastereomers in acetonitrile.

Dithiobenzoic esters and diphenylketene react by a mechanism of -cycloaddition with the formation of 4-alkylthio-2-thietanones.During thermolysis and electron impact the products readilly undergo both the retro reaction with the formation of the initial structures and cyclodecomposition with the elimination of carbon sulfoxide.

A facile one-pot reaction between carboxylic acids and S-alkyl phosphorus sulphides affords the corresponding alkyl dithioesters.

S-Methyl(S-ethyl)thio(dithio)carboxinium ions were prepared by reacting methyl(ethyl) fluoride-antimony pentafluoride with carbonyl sulfide (carbon disulfide) and studied with 1H and 13C NMR spectroscopy.The ions were subsequently used in the novel carboxylation reaction of arenes to S-methyl (S-ethyl) thio(dithio)benzoates.The method was also found to be adaptable to the carboxylation of polystyrene to poly(styrenecarboxylic acid) without degradation of the polymer backbone.

Electrochemical reduction of benzenecarbodithioic esters (1a-e) and carbothioic S-esters (2a-e) in aprotic medium yields diphenylacetylene; in the presence of an alkylating agent 1 forms a dithioacetal.Cyclic volttammetry shows that the heterogeneous electron transfer is quasireversible; it is followed by a relatively slow dimerization of the anion radicals.In the steps following the dimerization dithiobenzil is formed and 1 acts as a thioacylating agent. 2 behaves analogously to 1, but the follow-up reaction is faster.