Thiophosgene, reactions

Although the transformation of glycosylamines (such as 15) into fully unprotected glycosyl isothiocyanates by reaction with thiophosgene was already reported in the 1970s,58 61 these compounds were later shown to be unstable,62 and no further chemistry has been reported. Hie synthesis of stable, fully protected hexopyranosyl isothiocyanates by the thiophosgene reaction was first reported by Fuentes Mota and coworkers.63 65 Hie reaction sequence involves a glycosyl enamine (for example, 16) as key intermediate which., after O-prolection (->17), is hydrolyzed under mild condi-... 

Thiophosgene reacts with alcohols and phenols to form chlorothionoformates or thiocarbonates. The most studied reactions of thiophosgene are with primary amines to give isothiocyanates and with secondary amines to give thiocarbamyl chlorides ... 

The reaction of thiophosgene with various bisphenols using phase-transfer catalysis gives polythiocarbonates (44) ... 

Most of the reactions of thiophosgene involve the expected chemistry of an acid chloride, in which the chlorine atoms are replaceable by various nucleophiles. A reaction involving the C=S bond is the Diels-Alder addition ... 

Preparation. Thiophosgene forms from the reaction of carbon tetrachloride with hydrogen sulfide, sulfur, or various sulfides at elevated temperatures. Of more preparative value is the reduction of trichi oromethanesulfenyl chloride [594-42-3] by various reducing agents, eg, tin and hydrochloric acid, staimous chloride, iron and acetic acid, phosphoms, copper, sulfur dioxide with iodine catalyst, or hydrogen sulfide over charcoal or sihca gel catalyst (42,43). 

A similar utilization of two heteroatoms is illustrated by the reaction of the ethylenedithiol (120) with formic acid in the presence of perchloric acid. 4,5-Diphenyl-l,3-dithiolylium perchlorate (121) was formed in 45% yield (69MI40300). Introduction of a 2-oxo or 2-thioxo substituent as in (123 X = 0, S) is illustrated by the reaction of the disodium salt (122) with phosgene and thiophosgene, respectively (76S489). 

Reaction of aminothiophenol 97 with reagent 98 obtainable from phenyl urea and thiophosgene leads directly to the anthelmintic agent frentizole (99). In... 

Thiocarbonyl tetrachloride, 46, 21 m Thiocresol (Warning), 47, 107 Thionyl chloride, 46, 16 98 Thiophosgene 46, 21 Thiophosphoryl chloride, reaction with methylmagnesium bromide to i lelci tetramethylbiphosphine disulhdc 46,102... 

An inverse addition of sulfinic acid to a thiocarbonyl group could have taken place with the reactive intermediate 8, which should arise from thiophosgene and methanesulfmic acid (sodium salt)106 (equation 28). The first step of this reaction represents an S-acylation... 

Addition of thiophosgene to the reaction mixture of ImCSIm and trimethylsilylazide causes the yield to become quantitative.11301,11323 In the conversion with trimethylsilyl azide the required ImCSIm could also be made in situ from trimethylsilylimidazole and thiophosgene, giving the thiatriazoles in 70—80% yield.11321... 

Reaction of 2,6-dimethylaniline with thiophosgene produces isothiocyanate 171. When the latter is treated with 3-aminopropanol, thiourea 172 is formed, and this, when treated with hot concentrated hydrochloric acid, cyclizes to xylazine (173), an analgetic... 

Bis(benzotriazol-lyl)methanethione 974 is easily prepared from thiophosgene and l-(trimethylsilyl)benzotriazole <1978JOC337>. In reactions with thiols and triethylamine, thiones 974 are converted to derivatives 973 in modest yields the main side products result from nucleophilic attacks of the thiolate anions on the thione sulfur atom to produce disulfides <2005JOC7866>. In reactions with amines, compounds 974 are smoothly converted to l-(thiocarbamoyl)benzotriazoles 975 <2004JOC2976>. Substitution of one of the benzotriazolyl groups in 974 by phenolate anions yields l-(aryloxythioacyl)benzotriazoles 978 (Scheme 161) <2005JOC7866>. 

The reaction of tetrazole 132 with thiophosgene leads to [l,2,4]triazolo[3,4+][l,3,4]thiadiazoles 49. The reaction involves the in situ generation of aryldiazomethanes by decomposition of the tetrazole, followed by two cycloadditions (Equation 38) <1999CPA215>. 

Thiophenium salt derivatives, 23 715 Thiophilic adsorption, 6 405 Thiophosgene, 23 625-626, 4 837 reactions of, 23 625-626 Thiophthalimide vulcanization retarders, 21 800... 

In carbohydrate chemistry, the most described method for the preparation of saccharidic thionocarbamates involves preliminary introduction of the amine function on a partially or non-protected saccharidic template. The condensation of amino sugars with carbon disulfide or thiophosgene leads to cyclization in 1,3-oxazolidine- or l,3-oxazine-2-thiones. This reaction involves the formation of an intermediate isothiocyanate, which reacts further with a 3- or y-located hydroxyl group. The viability and facility of this process depends on the saccharidic ring size and the inherent strain. Some major rules can be put into light from the cases studied 30... 

Saccharidic templates bearing an amino group in C-2, C-6, C-3, C-5. Generally, an amine located on non-anomeric position reacts similarly through the condensation reaction with carbon disulfide or thiophosgene, the preliminary formed isothiocyanate leads to spontaneous or base-induced cyclization into 1,3-oxazolidine- or l,3-oxazine-2-thiones, as previously mentioned. Several extensive studies are reported about the selective introduction of thionocarbamate moieties on carbohydrate scaffolds.3 22 23 320 34 38... 

A different approach involving cyanohydrin formation from the 3-keto sugar was also explored in the D-Fru series (Scheme 17). A mixture of epimeric cyanohydrins was quantitatively formed by reaction with sodium cyanide in methanol, albeit without stereoselectivity. Chromatographic separation of (R)- and (A)-isomers was straightforward and the former epimer was selected to exemplify the two-step transformation into an OZT. Reduction of this nitrile by lithium aluminum hydride led to the corresponding aminoalcohol, which was further condensed with thiophosgene to afford the (3i )-spiro-OZT in ca. 30% overall yield. Despite its shorter pathway, the cyanohydrin route to the OZT was not exploited further, mainly because of the disappointing yields in the last two steps. 

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