11C-labelling of Ro 15-1788 in two different positions, and also 11C-labelling of its main metabolite Ro 15-3890, for PET studies of benzodiazepine receptors

Int J Rad Appl Instrum A. 1988;39(9):993-7. doi: 10.1016/0883-2889(88)90044-5.

Abstract

The benzodiazepine receptor antagonist Ro 15-1788 has been labelled with 11C in two different positions [( methyl-11C]Ro 15-1788 (I) and [ethyl-11C]Ro 15-1788 (II]. Product I was prepared by N-alkylation of the desmethyl compound (Ro 15-5528) with [11C]methyl iodide and product II was prepared by esterification of the desethyl compound (Ro 15-3890) with [11C]ethyl iodide. Ro 15-3890, the main metabolic product of Ro 15-1788, was labelled by two synthetic routes. In route A, [methyl-11C]Ro 15-3890 (III) was prepared by N-alkylation of the corresponding desmethyl compound (Ro 15-6877) with [11C]methyl iodide. In route B, III was prepared by a subsequent hydrolysis of I. The radiochemical yields were on the order of 15-60% (EOB) with an overall synthesis time of 40-50 min. Compounds I, II and III were isolated by semi-preparative HPLC and the radiochemical purity was in all cases greater than 99%.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Carbon Radioisotopes*
  • Flumazenil / analogs & derivatives*
  • Flumazenil / metabolism
  • Humans
  • Isotope Labeling / methods*
  • Receptors, GABA-A / analysis*
  • Tomography, Emission-Computed*

Substances

  • Carbon Radioisotopes
  • Receptors, GABA-A
  • Flumazenil
  • Ro 15-3890