DAINS ET AL.: ARYL ISOTHIOCYANATES. 13 



HALOGEN SUBSTITUTED PHENYL MUSTARD OILS. 

 m-BROMOPHENYL IsoTHiocYANATE. m-BrCgH^NCS. 



m-Bromoaniline 15 gms. 



Carbon bisulphide 10 gms. 



Ammonium hydroxide 13.6 gms. 



Lead nitrate 29.0 gms. in 500 cc. of water. 



The dithiocarbamate formed very slowly and coarse crystals of 

 the ammonium salt began to appear only after an hour's stirring. 

 These were dissolved in 500 cc. of water. 



The oil which came over with the steam solidified on cooling. The 

 yield, however, was only 7 gms. (37.4 per cent). 



P-Bromophenyl Isothiocyanate. p-BrCgH^NCS. 



The same quantity of reagents were used as in the preceding prep- 

 aration except that 15 cc. of alcohol was added in order to decrease 

 the solubility of the ammonium salt, which separated in the form 

 of fine, needle-shaped crystals. After standing overnight the mix- 

 ture was dissolved in 500 cc. of water and filtered from a little un- 

 changed p-bromoaniline. The yield of mustard oil was 39.6 per cent. 



P-Chlorophenyl Isothiocyanate. p-ClCgH^NCS. 



p-Chloroaniline 20.0 gms. 



Carbon bisulphide 15 . gms. 



Ammonium hj^droxide 24.5 gms. 



Alcohol : 20 cc. 



Lead nitrate 52 . gms. 



The mixture containing the ammonium dithiocarbamate was dis- 

 solved in 500 cc. of water and treated as usual. The yield was 15.8 

 gms. of the solid isothiocyanate (59.6% ) . 



p-IODOPHENYL IsOTHIOCYANATE. p-ICgH^NCS. 



p-Iodoaniline 20 gms. 



Carbon bisulphide 12 gms. 



Ammonium hj-droxide 14.2 gms. 



Alcohol 20 cc. 



Lead nitrate 30.2 gms. 



The crystals separated after 30 minutes' stirring. The mixture 

 after standing for four hours was added to 500 cc. of water, and 

 later filtered from a dark-colored insoluble residue. The mustard 

 oil, which was obtained in a 53.4 per cent yield, was volatile with 

 steam and melted at 79°. 



p-NlTROANILINE. 



All efforts to prepare the ammonium p-nitrophenyl dithiocar- 

 bamate failed, the nitroaniline being recovered unchanged. 



