Trithiocarbonates

Cycloadditions of benzonitril-4-nitrobenzylide to a variety of carbon to heteroatom multiple bonds including methyl dithiobenzoate and dimethyl trithiocarbonate (Scheme 148), X = MeS or Ph, have been examined in detail by Huisgen et al. (757). 

It is the sodium trithiocarbonate from this side reaction that gives the viscose dope its characteristic orange color. 

Similarly, carbon disulfide and propylene oxide reactions are cataly2ed by magnesium oxide to yield episulftdes (54), and by derivatives of diethyUiac to yield low molecular weight copolymers (55). Use of tertiary amines as catalysts under pressure produces propylene trithiocarbonate (56). 

In a typical batch operation, carbon disulfide is added to four molar equivalents of 25—30 wt % aqueous ammonia in a stirred vessel, which is kept closed for the first one to two hours. The reaction is moderately exothermic and requires cooling. After two to three hours, when substantially all of the disulfide has reacted, the reaction mixture is heated to decompose dithiocarbamate and trithiocarbonate and vented to an absorption system to collect ammonia, hydrogen sulfide, and any unreacted carbon disulfide. 

Many other routes to produce thioglycohc acid have been iavestigated (9). To try to minimise by-products, nucleophilic agents other than alkah sulfhydrates have been claimed, eg, thiosulfates, sodium disulfides, thiourea, xanthogenic acid derivatives, and sodium trithiocarbonates (10). These alternative methods, which require reduction of the disulfides or hydrolysis of carboxymethylthio derivatives, seem less competitive than those usiag alkah sulfhydrates. 

Further hydrolysis of the carbon disulfide and the trithiocarbonate produces hydrogen sulfide, etc (33). In another study of the decomposition of sodium ethyl xanthate [140-90-9] in flotation solutions, eleven components of breakdown were studied. The dependence of concentration of those components vs time was examined by solving a set of differential equations (34). 

Where no water is present, very pure xanthates form (65). Ethanol reacts slowly with sodium trithiocarbonate to produce sodium ethyl xanthate... 

Carbon disulfide slowly reacts with alkaH hydroxides to form trithiocarbonates and alkaH carbonates ... 

Trithiocarbonates can also be prepared from aqueous alkaH sulfides ... 

Carbon disulfide reacts with concentrated ammonia to give ammonium thiocyanate [1762-95-4] and ammonium trithiocarbonate [13453-08-2] in a reaction promoted by alumina catalysts ... 

Carbon disulfide reacts with ethylene oxide to give ethylene trithiocarbonate (90), and isocyanates yield derivatives of 2-oxazohdinone (91). 

Thiirenes have been isolated in argon matrices at 8 K by photolysis of 1,2,3-thiadiazoles or vinylene trithiocarbonates (Scheme 151) (80PAC1623, 8UA486). They are highly reactive and decompose to thioketenes and alkynes (Scheme 22). Electron withdrawing substituents stabilize thiirenes somewhat, but no known thiirene is stable at room temperature unlike the relatively stable thiirene 1-oxides and thiirene 1,1-dioxides. 

Vinylene sulfate — see 2,2-dioxide under 1,3,2-Dioxathiole Vinylene thiocarbonate synthesis, 6, 780 Vinylene trithiocarbonates photolysis, 7, 181 Violapterin... 

Thiocarbonyl compounds can be converted into difluoromethylene compounds usually under milder conditions than the conesponding carbonyl compounds Ethylene trithiocarbonate reacts smoothly with sulfur tetrafluoride at 110 °C in the absence of catalyst to give 2,2-difluoro-l,3-dithiolane in high yield. Thiuramsul/ides under similar conditions are readily converted into dialkyItrifluo-rometkylamines [11] (equations 13 and 14). 

Under similar conditions, perfluoroalkyl iodides react with alkyl phosphates to give fluorinated phosphine oxides, phosphinates, and phosphines [54 (equation 49) The product formed depends upon the stoichiometry and type of iodide used. When sodium alkyl trithiocarbonates are used as substrates, perfluoroalkyl tri-thiocarbonates ate formed [55]. 

Another boron sulfide, of stoichiometry BS2, can be made by heating B2S3 and sulfur to 300°C under very carefully defined conditions. It is a colourless, moisture-sensitive material with a porphine-like molecular structure, BgSig, as shown in Fig. 6.29b. An alternative route to BgSie involves the reaction of dibromotrithiadiborolane with trithiocarbonic acid in an H2S generator in dilute CS2 solution ... 

When ethanol is replaced by cellulose, sodium cellulose xanthate is obtained this dissolves in aqueous alkali to give a viscous solution (viscose) from which either viscose rayon or cellophane can be obtained by adding acid to regenerate the (reconstituted) cellulose. Trithiocarbonates (CS3 "), dithiocarbonates (COS2 "), xanthates (CS2OR ), difhiocarbamates (CS2NR2 ) and 1,2-dithiolates have an extensive coordination chemistry which has been reviewed. ... 

Schwefel-kobalt, m. cobalt sulfide, -kohle, /. sulfurous coal, high-sulfur coal, -kohlen-saure, /. sulfocarbonic acid (trithiocarbonic add, HaCSa). -kohlenstoff, m. carbon disulfide. -kolben, m. retort for distilling sulfur, -kora, -kbrachen, n. sulfur granule, -kuchen,... 

Thio-germaniumsaure, /. thiogermanic acid, -harnstoff, m. thiourea, -kohlensaure, /. thiocarbonic acid, specif, trithiocarbonic acid. H CSa. 

Living radical polymerization using thiocarbonylthio RAFT agents (including dithioesters, trithiocarbonates and xanthates) was first described in a patent published in 1998.40S The first paper describing the process also appeared in 1998.1R Other patents and papers soon followed. Papers on this method, along with NMP and ATRP, now dominate the literature on radical polymerization. 

O-Alkyl xanthates and A -ary l-A -alkyl dithiocarbamates are effective with vinyl acetate. 97 Dithioesters and trithiocarbonates give severe retardation or even inhibition which is attributed to slow fragmentation of the adduct radical. 

A similar approach has been used to prepare dithiocarbamates, xanlhates and unsymmetrical trithiocarbonates.478 Thus, unsymmetrical primary and secondary trithiocarbonates arc readily prepared in a one pot reaction by treating a thiol with carbon disulfide in the presence of triethylamine to form a carbotrilhioale salt and then adding the appropriate alkylating agent.457 47 The process is shown in Scheme 9.40 for 231.46j... 

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