OP ARTS AND SCIENCES. 141 



If 10 grams of o-tolylisocyanide be heated with 1^ molecules of 

 aniline for twenty-five minutes at 190°-220°, the reaction is com- 

 pleted, and no isonitrile left. In this case, however, not only 

 phenyl-o-tolylformamidine, 



.NHC 6 H 6 



ch 5 c 6 h 4 n=c; 



results, but a mixture from which I succeeded only in separating 

 out diphenylformamidine as a pure product. 



A similar result is obtained on heating 10 grams phenylisocyanide 

 with 10.5 grams o-toluidine for two hours at 190°-220° : from the 

 resulting mixture of amidine products, 0.4 gram of pure o-ditolyl- 

 formamidine (melting point 151°) could be isolated with ease. 



These experiments show that the addition of primary amines 

 takes place somewhat more readily in the case of o-tolylisocyanide 

 than with phenjdisocyanide; and further, that the resulting dial- 

 kylated formamidine derivatives, 



.NHR' 

 EN=Cf 

 X H 



are homogeneous only when the two alkyl groups (R and E/) are 

 the same. 



Action of Sulphur. — 5 grams o-tolylisocyanide and the calculated 

 amount of crystallized sulphur, in the presence of carbon bisulphide, 

 were heated in a sealed tube for two hours at 130°. No isonitrile 

 was left, and after distilling off the carbon bisulphide, the residue 

 was distilled with steam. The mustard oil thus carried over, 

 after extracting with ether and drying with calcic chloride, boiled, 

 on fractionating, at 236° -237° (thermometer entirely in the vapor) 

 at 726 mm. It was identical in all its properties with o-tolyl 

 mustard oil, * CH 3 -C 6 H 4 -N=C=S, and gave the following result on a 

 sulphur determination : 



0.2681 gram substance gave 0.4064 gram BaS0 4 (Carius). 



Theory for C 8 H 7 NS. Found. 



S 21.47 20.81 



Action of Hydrogen Sulphide. — An alcoholic solution of o-tolyl- 

 isocyanide was saturated at 0° with sulphuretted hydrogen, and 



* Girard, Ber. d. chem. Ges., VI. 445. 



