1) N,N-Dimethyl-2-aminoethanesulfonamide (I) is condensed with 2-chloroethyl isocyanate (II) by means of triethylamine in CHCl3 giving 1-(2-chloroethyl)- isocyanate (II) by means of triethylamine in CHCl3 giving 1-(2-chloroethyl)-3-[2-(dimethylsulfamoyl)ethyl]urea (III), which is nitrosated with NaNO3, N2O4 or NOCl in acetic acid-acetic anhydride.
2) By condensation of (I) with N-(2-chloroethyl)-N-nitrosocarbamoyl hydrazide (IV) in ethanol with triethylamine as catalyst.
3) By condensation of (I) with 1-[N-(2-chloroethyl)-N-nitrosocarbamoyloxy]pyrrolidine-2,5-dione (V) in methanol with triethylamine as catalyst.
4) By condensation of (I) with 4-nitrophenyl N-(2-chloroethyl)-N-nitrosocarbamate (VI) in methanol with triethylamine as before.