Mr Ruhemann, Dith ioxanth oxalanil and its Homologues. 199 
Bithioxanthoxalan.il and its Homologues. By S. Ruhemann, 
M.A., Gonville and Caius College. 
[ Read 11 March 1907.] 
Similar to the action of ethyl oxalate on acetanilide and its 
homologues (Trans. Cheni. Soc. 1906, lxxxix. 1236, 1847) is the 
behaviour of thioacetanilide and its homologues towards the ester. 
This reaction yields compounds, the representative of which, 
dithioxanthoxalanil, is to be expressed by the formula : 
/CS — CH., CO — CO x 
C 6 H 5 .N( I I >n.c 6 h 5 . 
x CO — c = c — cs x 
With regard to their colour I find that they shew similar 
differences to the corresponding members of the xanthoxalanil 
group, dithioxanthoxalanil being dark brown, whereas its homo- 
logues have a lighter shade. The dithio-derivatives have no 
acidic properties, and in this respect resemble the other class 
of compounds ; they differ, however, from them by their greater 
stability towards alkalis. Xanthoxalanil, for instance, on warm- 
ing with dilute caustic potash, is decomposed, and yields aniline, 
dianilaconitic acid and oxalic acid. No similar decomposition 
takes place on digesting dithioxanthoxalanil with the dilute 
alkali, instead of it the compound is transformed into its 
tautomeride which readily dissolves in caustic alkalis as well 
as their carbonates, and therefore is to be represented by the 
formula : 
c g h 5 .n 
/ 
\ 
C (SH) : CH CO — CO 
I I 
CO — C = C — CS 
\ 
/ 
N.c 6 H 5 . 
On boiling dithioxanthoxalanil with caustic potash (15 — 20 
per cent.) for some hours, one atom of sulphur is replaced by 
oxygen and a substance thioxanthoxalanil is produced which 
dissolves in sodium carbonate. This behaviour points to the 
following symbol : 
C,H, . N 
/C (SH) : CH CO — CO\ 
\ I I >n.c„h 5 . 
x CO — C = C — CO 
A complete decomposition of dithioxanthoxalanil does not take 
place until it is boiled with quite concentrated caustic potash 
(60 — 70 per cent.). 
