5415-95-2

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.

The present invention provides compounds of Formula 1: or pharmaceutical acceptable salts thereof wherein A, G and R1are as defined in the claims which are antibacterial agents.

The invention relates to carbapenem derivatives useful as antimicrobial agents, more particularly to intermediate compounds for the preparations thereof of the formula STR1

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Tris(trimethylsilyl)methanethiol, prepared from tris(trimethylsilyl)methane, can be easily converted into bis(trimethylsilyl)methanethiol and this to bis(trimethylsilyl)methyl alkanethiosulfinate esters; the latter upon heating afford alkyl trimethylsilyldithioformates via bis(trimethylsilyl)thione, which can be trapped with dienes.

Cis lithium thioenolates are preferentially formed by deprotonation of dithiopropanoates with lithium diisopropylamide in tetrahydrofuran at -78deg C.The cis selectivity observed, is improved by increasing the alkylthio group size or by the ability of this group to chelate the lithium cation.When more bulkier bases such as lithium 2,2,6,6-tetramethylpiperidide or lithium hexamethyldisilazane are used, the selectivity is lowered.This lowering of selectivity is suppressed when the deprotonation is performed in presence of 12-crown-4.Addition of hexamethyl phosphoramide to the base does not invert the selectivity as it was reported for the deprotonation of esters ; a rather better cis selectivity is reached in the case of methoxymethyl dithiopropanoate.These original results are well understood in terms of an open transition state model.Preformed lithium thioenolates are reacted with a variety of aldehydes and affored stereospecifically syn aldols.The influence of hexamethylphosphoramide and reaction time is also examined.

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.

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