A convenient method to synthesize N-[3H]methyl-N-nitrosocarbamate transfer reagents

Activated N-alkyl-N-nitrosocarbamates are useful acyl transfer reagents that are employed in the synthesis of N-alkyl-N-nitrosoureas and related N-nitroso compounds. The nitrosourea products are of chemical and biological interest because they provide access to the in situ generation of highly reactive carbonium type intermediates, which, depending on their structure, can be powerful carcinogens or antineoplastic agents. The availability of radiolabeled nitrosoureas greatly facilitates studies on their chemical and biological activities. Generally, the synthesis of activated nitrosocarbamates requires condensation of radiolabeled alkylisocyanates with the appopriate alcohol. Because radiolabeled alkylisocyanates are not commercially available and/or troublesome to synthesize, we have developed an easy and economical method for preparing N-[3H]methyl-N-nitrosocarbamates suitable for use as transfer reagents utilizing 1,2,2,2-tetrachloroethyl chloroformate and [3H]methylamine hydrochloride as starting materials.