The acylation of N-hydroxysuccinimide (I) with 2-chloroethyl isocyanate (II) gives N-(2-chloroethyl)carbamoyloxysuccinimide (III), which is nitrosated with NaNO2 - HCl to the corresponding N-nitroso derivative (IV). Finally this compound is allowed to react with beta-D-glucosamine (V).
The reaction of beta-D-glucosamine (I) with 2-chloroethyl isocyanate (II) in water or DMF gives 2-[3-(2-chloroethyl)ureido]-2-deoxy-D-glucopyranose (III) (1,2), which is then nitrosated with N2O3 in concentrated HCl (1); or with NaNO2 and HCl in ethanol - water (2), or in acetic acid (3).