Synthesis of "no-carrier-added" carbon-11 SarCNU: the sarcosinamide analog of the chemotherapeutic agent BCNU.

Carbon-11-labeled SarCNU [N-(2-chloroethyl)-N-nitroso-N'-(carboxamidomethylene)-N'-(methyl) - [11C]-urea], a potential chemotherapeutic agent, has been prepared by the nitrosation of the corresponding urea, N-(2-chloroethyl)-N'-(carboxamidomethylene)-N'-(methyl) [11C]urea (SarCU). SarCU was prepared by reacting sarcosinamide with [11C]-2-chloroethylisocyanate, which was itself prepared by reacting [11C]-phosgene with 2-chloroethylamine hydrochloride suspended in dioxane. The synthesis yielded [11C]SarCNU with an average radiochemical purity of 95% in an average overall radiochemical yield of 18% relative to the activity measured at the end of [11C]phosgene introduction.