Synthesis of 11C-labelled N,N’-diphenylurea and ethyl phenylcarbamate by rhodium-promoted carbonylation reaction via [11C]-isocyanatobenzene using phenyl azide and [11C]carbon monoxide
2004 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 2, no 21, 3063-3066 p.Article in journal (Refereed) Published
The reaction with phenyl azide and [11C]carbon monoxide to give N,N'-diphenyl[11C]urea and ethyl phenyl[11C]carbamate has been studied with the aim of development of a new methodology for carbonylation using [11C]carbon monoxide with high specific radioactivity. The synthesis of 11C-labelled N,N'-diphenylurea from phenyl azide and [11C]carbon monoxide, with 1,2-bis(diphenylphosphino)ethane-bound Rh(I) complex at 120 degrees C at a pressure of 35 MPa in the presence of aniline was accomplished in 82% trapping efficiency and 82% conversion yield. This approach was also useful for the synthesis of ethyl phenyl[11C]carbamate with lithium ethoxide as a nucleophilic reagent giving 90% trapping efficiency and 76% conversion yield. These reactions can be considered to proceed via a [11C]isocyanate or a [11C]isocyanate-coordinated Rh complex to give the corresponding 11C-products. This protocol provides the chemical basis for the synthesis of [11C]urea and [11C]carbamate derived from [11C]isocyanates.
Place, publisher, year, edition, pages
2004. Vol. 2, no 21, 3063-3066 p.
IdentifiersURN: urn:nbn:se:uu:diva-94170DOI: 10.1039/B409294EPubMedID: 15505707OAI: oai:DiVA.org:uu-94170DiVA: diva2:167930