title: Production of [11C]chloroform by direct chlorination of [11C]methane without catalyst support for the synthesis of [11C]diazomethane.
abstract: The preparation of [11C]chloroform by direct chlorination of [11C]methane using gaseous chlorine by variation of temperature and reaction time (inert gas flow) without catalyst support for the online production of [11C]diazomethane in a flow-through synthesis apparatus is described in this work. At an oven temperature of 400 degrees C and a He flow of 50 mL/min, [11C]chloroform was synthesized inside a quartz glass column in a radiochemical yield of 31+/-2% with respect to [11C]methane. The online preparation of [11C]diazomethane by reaction of [11C]chloroform with hydrazine in an ethanolic KOH solution with small amounts of 18-crown-6-crownether succeeded with a radiochemical yield of 20+/-3% with respect to [11C]methane. The product [11C]diazomethane was measured indirectly in the form of 4-nitrobenzoic acid[11C]methylester using the esterification of 4-nitrobenzoic acid as a monitor reaction.
authors.affiliation: Radiopharmacy, PET-Center, University Hospital Tübingen, Röntgenweg 15, D-72076 Tübingen, Germany. christoph.solbach@uni-tuebingen.de
authors.forename: C
authors.initials: C
authors.lastname: Solbach
authors.forename: H-J
authors.initials: HJ
authors.lastname: Machulla
mesh_terms: D002250:Carbon Radioisotopes / Q000737:chemistry*; D002384:Catalysis; D002725:Chloroform / Q000138:chemical synthesis / Q000737:chemistry; D003978:Diazomethane / Q000138:chemical synthesis* / Q000737:chemistry; D006801:Humans; D008697:Methane / Q000737:chemistry; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D003978:Diazomethane; D002725:Chloroform; D008697:Methane