BEAUI'IONS OF ORGAXIU TEIWULPHATES. 2887 CCCC.-Reuctiom of Organic Thiosulphatea. By HENRY BELL FOOTNER and SAMUEL SMILES. ABUNDANT evidence is available showing the instability of the disulphoxides which are to be regarded as containing the thiol-sulphomte structure *S*SO,* (this vol. p. 224) and the ease with which their sulphur chain may be r u p t d . To ascertain whether this type of reaction is exhibited by the thiosulphonate group under other structural conditions the organic sodium thio-sulphates which owing to the work of Price and Twiss (J. 1907, 91 2021) may be confidently assumed to have the thiol-sulphate structure RS*SO,*ONa have been examined. In aqueous solu-tion these substances are very readily decomposed by odium mercaptides and by alkali cyanide.The former reagent quickly yields a t the ordinary temperature sodium sulphite and an in-soluble product composed of a disulphide or a mixture of disulphides, according to the mercaptide used, RS-SO;Na + NaSR = RS-SR' + Na$03. When R and R' axe the same this product is homogeneous and consisfs of a symmetrical disulphide but when they ar 28SS FOOTNER ANT) SMTLES : c2issimilar it is in most cases a mixture of the two possible symmetrical disulphides; only in a few instances has the un-symmetrical disulphide been isolated. This behaviour is closely pamllel to that of the disulphoxides (J. 1924 125 176), RS*SO,R + R’SNa = RS-SR’ + RSOga, and the formation of the mixture of symmetrical disulphides is adequately explained by the secondary reaction of fhe mereaptide with disulphide (Lecher Ber.1920 53 591): RS*SR’ + NaSR GRS-SR 4- R’SNa. The organic thiosulphates are also quickly decomposed by nqucoiis alkali cyanide more than 90% reacting thus : RS*SO$Ta + NaCN = RSCN + Na,SO,. The products are almost pure and the yields being excellent the method is well adapted to the preparation of thiocyanates when the corresponding thiosulphates are available. According in un-published experiments the disulphoxides behave in a similar manner, RS*SO,R + NaCN = RSO,Na + RSCN, but are much less reactive. The interaction of mercaptans and di-p-toluenesulphonyl sulphide (Troger J . pr. Chern. 1899 60 117) has also been examined with similar results, (C,H,=SO,),S + 2RSNa = C,H,*SO,-SNa + C,H,*SO,Na + (RS),, the sulphur chain being ruptured with formation of sulphinate and thiosulphonate together with the disulphide corresponding to the mercaptan used.According then to these experiments and others previously made with disulphoxides the characteristic reactions of the thiol-sulphone group in substances of the type RS*SO,*X are mainly due to instability of the dithio-system; this group is readily split by alkali mercaptides and with varying ease by other reagents, the activity depending on the character of the group X. Experiments have also been made with the polythionates. Sodium dithionate is not attacked by alkali mercaptides but the tri- and tetra-thionates are rapidly decomposed the disulphide being formed in both cases. The trithionate is resolved into sulphite and thiosulphate and the tetrathionate into thiosulphate.The completed reactions, Na,S,O + 2RSNa = (RS) + Na2S0 + N%S,O, Na,S,O + 2RSNa = (RS) + 2Na2S203, may be regarded as analogous to the reduction of these substances by sodium amalgam. Strictly quantitative measurements have no REACTIONS OF ORGANIC THLOSULPHATES. 3889 been made but more than 90% of the materials undergo the reactions indicated. Whilst the constitution of the polythionates is undeter-mined nothing further can be said of the nature of these reactions but bearing in mind the known behaviour of merctmptides with the dithio and thiohulphone systems the processes are in the authors' opinion adequately explained by the structures proposed by Mendelbv for the polythionates. In this comexion the close resemblance of the behaviour of the trithionate to that of ditoluene-sulphonyl sulphide is significant.E x P E R I M E N T A L. Reaction of Organic T h > W p - with Sodium Mercuptidtw-The benzyl and jp-nitrobenzyl thiosulphates used were prepared by Price and Twiss's method (Eoc. cit.) and the 9-anthryl thio-sulphate by Friedlander's (Ber. 1922 55 3969). The sodium mercaptide (1 mol.) and the thiosulphate (1 mol.) reacted rapidly in aqueous solution a t the ordinary temperature. After Q hour, the solution was neutral and contained sulphite with at the most only traces of sulphate. The yield of the precipitated disulphides generally exceeded 95%. The results from six of the cases examined are in the following table : Bemyl. BeIIZyl. Benzyl disulphide 99%.2-Nitrophenyl. Bewl. Benzyl 2-nitrophenyl disulphide, 9-Anthryl. Benzyl. Dianthryl dibenzyl and anthryl 2 - Nitr ophenyl . 4-Nitrobenzyl. 2-Nitrophenyl and 4-nitrobenzyl di-2 5-Dichlorophenyl. 9-Anthryl. Dianthryl and tetrachlomdiphenyl 2 -Ni trophen y 1. 9-Anthryl. 2-Nitrophenyl and anthryl di-The symmetrical disulphides named have been previously de-scribed. Benzyl 2-nitruphenyl disulphide separated from alcohol in yellow needles m. p. 54" (Found N 5.4; S 23.3. C1,HllO~S requires N 5-05; S 23.1%). The melting point of an equimolecular mixture of the two symmetrical disulphides was lowered by admixture with this substance. Benzyl 9-anthryl dkdphide was isolated from warm alcohol in yellow prisms m. p. 128". When it was mixed with equimolar proportions of dibenzyl and dianthryl disulphides its melting point was lowered (Found C 75.5 ; H 4.4; S 19.5.C,,H1&3, R & h of Organic Thiosulphutes with Alkali Cyanide.-On Memaptan. Thiosulphate. Products. 99%. benzyl disulphides. sulphides. disulphides. sulphides. requke~ C 75.9; H 4.8; S 19.3%) 2890 REACTIONS OF ORGANIC THIOSULPHhTES. miXing aqueous solutions of potassium cyanide and the thio-sulphate (equal mols.) reaction quickly ensued. It waa completed by keeping the mixture for various periods generally Q hour Qr was assisted by maintaining the temperature at about 30". The yield of thiocyanate which separated practically pure in most case8 was almost quantitative and a corresponding amount of sulphite was found in the aqueous liquor.In this way the following thiocyanates were isolated. Benzyl thiocyanate m. p. 41" (Found N 9.7; S 21.3. Calc., N 9.4; S 21.5%). 2-Nitrobenzyl thiocyanate m. p. 71" (Found N 14.7. Calc., N 14.4%). Cassira (Ber. 1892 25 3028) gives the m. p. of this substance as 75". 4-Nitrobenzyl thiocyanate colourless prisms m. p. 79" from warm alcohol (Found N 14.1; S 16-4. C,H,O,N,S requires N 14.4; S 16.5%). 9-Anthryl thiocyanute pale yellow needles m. p. 181" from hot alcohol (Found N 6.4; S 13.4. C,,HPS requires N 6.5; S 13.6%). Reaction of Di-p-toluenesUl.phon~l Sulphide with Hermphm.-An alcoholic solution of the mercaptide (2 moh.) and the sulphide ( 1 mol.) containing 5 g. in 100-150 C.C. was warmed on the water-bath and the solvent was then evaporated water being added towards the completion of the process.The insoluble product, in all the cases examined was the disulphide corresponding to the mercaptan taken. The solution containing sulphinate and thiosulphonate was acidified and gently warmed to decompose the latter; after the addition of aqueous sodium carbonate the coagulated sulphur was collected and the filtrate again rendered acid. The liberated sulphinic acid was in each case p-toluene-sulphinic acid. The disulphides obtained in this way from 2 5-dichlorophenyl, 6-methoxy-m-tolyl and 3-chloro-6-methoxyphenyl mercaptans were identified by comparison with authentic samples from other sources. Reaction of Sodium Tetruthion.de with Mermptides.-A typical experiment was as follows. A solution of 5 g .(2 mols.) of 6-methoxy-m-tolyl mercaptan in a small volume of alcohol was exactly neutral-ised with aqueous sodium hydroxide and added to a stirred solution of 7-5 g. (1 mol;) of sodium tetrathionate in 200 C.C. of water. The disulphide separated a t once but the mixture was kept for an hour before the solid WM collected. The filtrate contained thio-sulphate but no sulphite. Determinations of the iodine value were made and the roughly quantitative data obtained agreed well with the equation previously given; e.g. (a) 6-methoxy OBSERVATIONS ON THE CLAI!3EN REACTION. 2891 m-tolyl mercaptan I value 92% ; disdphide 97% of theory, (b) 3-chloro-6-methoxyphenyl mercaptan I value 95% ; di-sulphide 95% (c) 2 5-dichlorophenyl mercaptan I value 98%; disulphide 99%. Reaction of Sodium Trithionate with Mermptam.-The method of experiment was the same as the preceding. With benzyl, 6-methoxy-m-toly1 and 2 5-dichlorophenyl memaptans the di-dphides were isolated in 99-100~o of the yields required by the equation previously given whilat the approximate iodine values of the fltmtm were about 90%. Estimation of the sulphite in the case of 6-methoxy-m-tolyl mercaptan showed 99-100~o of the theoretical amount of this salt to be present in the aqueous liquor. We desk to thank the Department of ScientSc and Industrial Research for a grant which enabled one of us to take part in fhis work. KING'S COLLEGE LONDON. [Received November W 1926.