Synthesis of N-[1-13C]caproyl-N′-phenylthiourea

An optimal synthesis of N-[1-C-13]caproyl-M-phenylthiourea with isotopic enrichment 82% is described, starting from barium [C-13]carbonate, using five synthetic steps. Yields were 95% relative to caproyl chloride and 46% relative to barium carbonate. Oxidation of the title compound with manganese dioxide yields the corresponding ureide. Structural similarities with anticonvulsants such as phenacemide make N-caproyl-N'-phenylthiourea an interesting model compound. Copyright (C) 2004 John Wiley Sons, Ltd.