Trithianes, reactions

For 1,3,5-trithiane, reactions of the substituents attached to the heterocyclic ring system have been published. 2-Chloro-l,3,5-trithiane 174 reacts with isopropyl diphenyl phosphine oxide to yield the corresponding phosphine oxides 175, which were easily converted into the thiophosphoryl analogs 176 upon treatment with phosphorus pentasulfide (Scheme 46) <1987PAC983>. While the position of the phosphoryl group in the 1,3,5-trithiane 175 is exclusively axial, the thiophosphoryl derivative exists in solution as a mixture of axial and equatorial conformers. Furthermore, 2,4,6-tri(2-chloroethyl)-1,3,5-trithiane reacts with sodium diphenylarsenide in liquid ammonia to yield... 

The diethyl l,2,3,4-tetrathiepane-6,6-dicarboxylate (8) has been identified from the reaction mixture of diethyl bis(p-tolylsulfonyloxymethyl)malonate and tetrasulfide ion, along with 1,2-dithio-lane and 1,2,3-trithiane. Reaction of 1,2-dithiolane with elemental sulfur in DMF at elevated temperatures is a useful route to (8) (Equation (13)) <88ACS(B)620>. 

Thermolysis of trithiane (69) or carbonate (70) at reduced pressure yields methylene-thiirane which is stable in cold, dilute solution (Scheme 152) (78JA7436, 78RTC214). A novel acenaphthylene episulfide is obtained by treatment of the six-membered sulfoxide (71) with acetic anhydride (Scheme 153) (68JA1676), and photolysis of (72) gives a low yield of episulfide (73 Scheme 154) (72JA521). Low yields may be due to the desulfurization of the thiiranes under the reaction conditions. 

Reaction of the anion derived from the tosyl imide of l,3,S-trithiane with alkyl iodides gives a mixture of the mono- and di- alkylated products, in which anti stereochemistry predominates. The analogous 1,3-dithiane derivative is only monoalkylated <96JCS(P1)313>. 

The resistance of the E14-S bond in cyclotrimetallathianes toward nucleophilic reagents, for example, water and alcohol,62 increases on going from the silicon compounds to the corresponding germanium and tin derivatives. This is due, most likely, to the fact that the reaction of less nucleophilic ylides with phenyl groups at the phosphorus atom with trithianes (R2MS)3 (M = Ge, Sn) occurs slowly and is impeded by several side processes. 

A. Chloromethanesulfonyl chloride. A slurry of 210 g. (1.52 moles) of s-trithiane (Note 1) in a mixture of 1 1. of glacial acetic acid and 210 ml. of water is prepared in a 2-1., three-necked, round-bottomed flask equipped with an efficient mechanical stirrer, a thermometer, a coarsely fritted gas inlet tube (Note 2), and an exit tube by which excess fumes are carried to the rear of the hood. The flask is immersed in an ice bath, and the stirrer is started. A stream of chlorine is introduced at such a rate (Note 3) that the temperature of the mixture is maintained between 40° and 50° by the mildly exothermic reaction. After 1-2 hours a yellow solution results. To this solution is added 300 ml. of water, at which point the temperature rises to ca. 60°. 

Chemical/Physical. Although no products were identified, the estimated hydrolysis half-life in water at 25 °C and pH 7 is 44 yr (Mabey and Mill, 1978). Bromochloromethane reacts with bisulfide ion (HS ), produced by microbial reduction of sulfate, forming 1,3,5-trithiane and dithiomethane. Estimated reaction rate constants at 25 and 35 °C were 7.29 x 10 and 2.42 x 10 VM-sec, respectively (Roberts et al, 1992). 

Tirey et al. (1993) evaluated the degradation of phorate at three different temperatures. When oxidized at temperatures of 200, 250, and 275 °C, the following reaction products were identified by GC/MS ethanol, ethanethiol, methyl mercaptan, 1,2,4-trithiolane, 1,1-thiobisethane, 1,1 -(methylenebis(thio))bisethane, 1,3,5-trithiane, 0,0-diethyl-5-pentenyl phosphorodithioic acid, ethylthioacetic acid, diethyl disulfide, 2,2 -dithiobisethanol, ethyl-(1-methylpropyl) disulfide, sulfur dioxide, carbon monoxide, carbon dioxide, sulfuric acid, and phosphine. 

The procedure described here provides a convenient route to aldehydes with trithiane serving as an inexpensive, masked carbonyl group.2-4 The reaction is limited, however, to the use of primary alkyl halides, aldehydes, and ketones for elaboration of the carbon chain through attack on the metallated trithiane. Examples of aldehydes synthesized by this method are given in Table I. 

Tetradecyl-sym-trithiane, by reaction of 1-bromotetradecane with sym-trithiane in presence of -butyl-lithium, 51,39... 

Thioformaldehyde is unknown in the free state, but polymers of it have been obtained by ring opening of trithiane, by removal of hydrogen sulfide from methanedithiol, by reaction of formaldehyde and hydrogen sulfide or sodium sulfide, and by reaction of sodium hydrosulfide with methylene chloride. The... 

Most of the research on thioformaldehyde derivatives has been done on other products formed from formaldehyde and hydrogen sulfide. This reaction is quite complex and gives in addition to methanedithiol and bis(mercaptomethyl)sulfide, trithiane, thioformaldehyde oligomers, and poly(thioformaldehyde). 

In 1868 Hofmann (7) reported the preparation of trithiane. This is the product obtained when the hydrogen sulfide-formaldehyde reaction is run under strongly acidic conditions. Under weakly acidic or mildly alkaline conditions, the product formed retains significant amounts of oxygen. Recently, Credali and Russo (8) have examined in depth the reaction of hydrogen sulfide with aqueous formaldehyde free of added acid or base. 

Poly(thioformaldehyde) can also be obtained by reaction of hydrogen sulfide with formaldehyde in acid media (8). Again the key intermediate is 1-hydroxy-2-oxa-4,6-dithioheptane-7-thiol. Though acid conditions favor formation of trithiane, use of a high CH20/H2S04 ratio results only in polymer formation. Credali and Russo (8) believe this to be a topochemical reaction between the dithioheptane and mercaptomethanol. 

In addition to the polymer, the reaction of alkaline sulfides and hydrosulfides with methylene chloride gives trithiane (16), 1,3,5,7-tetrathiorane (16), and 1,3,5,7,9-pentathiacyclodecane (18). 

Thioacetone was first made in 1889 by Baumann and Fromm (31). They obtained it by reaction of hydrogen sulfide with acetone in the presence of an acidic catalyst. It was a minor product detected by its very disagreeable odor. The major product was hexamethyl-s-trithiane. In more recent work (32, 33) pyrolysis of this intermediate has been developed into a preferred route to thioacetone. 

Reaction of acetone with hydrogen sulfide in the presence of acidified ZnCl2 at 25° C gives a good yield of a product composed of60-70% hexamethyltrithiane and 30-40% of 2,2-propanedithiol. Thioacetone can be obtained by pyrolysis of either of these compounds. The trithiane is pyrolyzed either on quartz rings heated to 500-650° C at 5-20 mm (30) or by means of a hot wire (32). The dithiol is pyrolyzed on sodium fluoride pellets heated to 150° C at 11 mm (50). In both cases the pyrolysate is immediately collected in a trap cooled to — 78° C. 

The reaction of acetone and hydrogen sulfide gives, in addition to hexamethyl-s-trithiane, small amounts of two isomeric impurities, 2,3,5,5,6,6-hexamethyl-1,2,4-trithiane and 4-mercapto-2,2,4,6,6-pentamethyl-l,3-dithiane (32). 

Trithianes are rare but routes established for the 3-methyl derivative (226) could provide the basis of more general methods. These include the chlorination of diethyl disulfide and the reaction of the sulfenyl chloride (227) with 1,2-ethanedithiol (74MI22601). 1,2,4,5-Tetrathiane (228) has been prepared by the cyclization of two equivalents of the bis sulfenyl chloride CH2Y2 (229 Y = SCI) or the bis Bunte salt CH2Y2 (230 Y = SSQ3Na) using sodium... 

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