26028-04-6

A range of 18 alkoxycarbonyl sulfinyl phosphorus ylides 9 have been prepared and their behaviour upon flash vacuum pyrolysis (FVP) at 600 deg C examined. For R1 = H, Me and Et they lose Ph3PO and in some cases Ph3P to give mixtures of products including the alkenyl sulfides 10, the sulfides 11, the disulfides 12 and the thioesters 14. The alkenyl sulfides 10 most likely arise from intramolecular insertion of the alkoxycarbonyl sulfenyl carbenes resulting from loss off Ph3PO to produce β-lactones which then lose CO2 and this is supported by the results from 13C labelled ylides. Possible mechanisms for the formation of 11 and 14 are also presented and the feasibility of various steps has been examined by preparation and pyrolysis of the proposed intermediates. In contrast, pyrolysis of the ylides 9 where R1 = Ph and the tert-butoxycarbonyl ylides 30 leads mainly to complete fragmentation with loss of Ph3PO and benzyl alcohol or 2-methylpropan-2-ol and does not give any useful sulfur-containing products. Four alkoxy-carbonyl sulfonyl diazo compounds 33 have been prepared and in three cases they give the alkenyl sulfones 34 upon FVP at 400 deg C, probably by an intramolecular insertion and decarboxylation process analogous to the formation of 10 from 9. On the other hand the alkoxycarbonyl carbenes produced by FVP of the amino acid-derived diazo compounds 35 undergo alternative proocesses with no sign of β-lactone formation. Fully assigned 13C NMR data are presented for 13 of the ylides.

The N-protected α-amino amides 1 are O-alkylated with trialkyloxonium tetrafluoroborates to form the iminium salts 2.Sulfhydrolysis of 2 yields the α-amino thiono esters 3.This reaction sequence allows the preparation of enantiomerically pure 3.Key Words:

A variety of 2-arylpyridothiazepin-4(5H)-ones has been efficiently synthesized by treatment of the anion of 2-chloro-3-(N-methylacetamido)- and -3-acetamidopyridine with the appropriate O-ethyl thiocarboxylate.

2-Alkyl- and 2-aryl-4-oxo-4H-thiopyranopyridine can be conveniently prepared by reacting the appropriate aromatic and aliphatic O-ethyl thiocarboxylates with the sodium derivative of various alkyl 3-(2-bromopyridyl) ketones.

The synthesis of three aza-analogues of benzothiazole derivatives possessing calcium antagonistic properties has been achieved.

2-Aryl and alkyl pyrido -1,3-thiazine-4(4H)-ones, a class of previously unknown compounds can be conveniently prepared by treatment of the sodium anion of 2-chloronicotinamide with various aromatic and aliphatic thioesters.Their reduction with sodi

A series of Se-aryl carboselenothioates 3 (RCSSeAr, R=alkyl, aryl) were synthesized and characterized from the reaction of bis(thioacyl) sulfides 1 with sodium areneselenolates.The thionselenolesters 3 are stable (liquid or crystals) both thermally and to moisture.Reactions of 3 with aliphatic primary and secondary amines gave the corresponding ammonium carbodithioates 8 together with diphenyl diselenide 7.In contrast, treatment with aromatic amines or sodium alcoholates afforded the corresponding thioamides or O-alkyl or O-aryl thionoesters in good yields.The oxidation of 3 with m-chloroperbenzoic acid gave the corresponding sulfides 12 and acyl arylseleno sulfides 13 which are formed by a rearrangement of the ArSe group to the thiocarbonyl sulfur atom.

The reaction of sodium or caesium dithiocarboxylates with diphenylthiophosphinic and diphenylselenophosphinic chlorides gives purple thioacyl diphenylthiophosphinoyl 5 and dark green thioacyl diphenylselenophosphinoyl sulfides 6, which are useful thioacylating reagents under mild reaction conditions.Thioacyl diphenylphosphino sulfides 22, which can be obtained by the similar method using diphenylphosphinous chlorides, react with methanol to yield the corresponding methyl dithiocarboxylates 15, while the reactions of 22 with N-chlorosuccinimide lead to hitherto unknown N-(thioacetylthio)succinimides 28.

Hydrogen sulfide reacts with the N,N-dimethylformamide acetal 1 to give N,N-(dimethyl)thioformamide (2a).The thioamides 2a-e and the thiolactams 2f,g are prepared by thiolysis of the nitriles 3a-g.The action of hydrogen sulfide on nitriles 5a-f affords the O-ethyl thiocarboxylates 6a-f.The preparation of the nitriles 3g and 5a-f is described.

Reaction of dithioic acids with dicyclohexylcarbodiimide has been found to give the corresponding bis(thioacyl) sulfides 1 in good yield, which are very useful thioacylating reagents under mild reaction conditions.Most of the aromatic thioanhydrides (1, R = aromatic) are fairly stable green crystals at room temperature, but the aliphatic ones (1, R = aliphatic) are unstable purple oils which dimerize at room temperature to give the dithietanes 5.The reactions with nucleophiles are discussed.

It has been found that the reaction of diphenylmercury with an equimolar amount of thio- or dithio acids gave the corresponding phenylmercury thio- (1) or dithiocarboxylates (2), quantitatively, which further react with thio- or dithio acids to give mercury bis(thio-) (3) or bis(dithiocarboxylates) (4).The phenylmercury dithio salts (2) were found to be the very useful thioacylating agents for primary and secondary amines.The reaction of mercury bis(thiocarboxylates) (3) with dithiocarboxylic acids gave the unsymmetrical thio- and dithiocarboxylic acid mercury salts (5) in good yield. - Keywords: Phenylmercury Thiocarboxylates