Fluorescent-labeled ligands for the benzodiazepine receptor. Part 1: Synthesis and characterization of fluorescent-labeled benzodiazepines.
Because radioactive labeled ligands in receptor assays have several disadvantages, we synthesized a number of fluorescent-labeled benzodiazepines. Several fluorophores were attached at different positions of 1,4-benzodiazepine molecules in order to assess the impact of the fluorophores and their coupling position on the affinity for the benzodiazepine receptor. Besides the 1,4-benzodiazepines, the 1,2-annelated 1,4-benzodiazepines were also used for labeling. A metabolite of flumazenil (18), desethylflumazenil (Ro15-3890, 19), was labeled with the fluorophore 4-bromomethyl-7-methoxycoumarin, with and without the incorporation of a spacer chain, yielding the methyl-methoxycoumarin (Mmc) derivatives Mmc-Ro15-3890 (20a) and Mmc-O-CO-(CH2)3-Ro15-3890 (20b), respectively. After the synthesis, the fluorescent-labeled benzodiazepines were purified by HPLC, using an analytical RP-C18 column. For the purification of 20b, the chromatographic system was optimized, using multi-criteria decision making (MCDM) techniques. The binding affinities for the benzodiazepine receptor and the fluorescence characteristics were determined for the resulting products.
Janssen
M J
MJ
Department of Analytical Chemistry and Toxicology, University Centre for Pharmacy, Wageningen, The Netherlands.
Hulst
R
R
Kellogg
R M
RM
Hendriks
M M
MM
Ensing
K
K
de Zeeuw
R A
RA
D000818:Animals; D001569:Benzodiazepines / Q000138:chemical synthesis* / Q000737:chemistry; D001923:Brain Chemistry; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D005442:Flumazenil / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D018757:GABA Modulators / Q000737:chemistry; D066298:In Vitro Techniques; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008566:Membranes / Q000378:metabolism; D011869:Radioligand Assay; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
D005456:Fluorescent Dyes; D018757:GABA Modulators; D008024:Ligands; D011963:Receptors, GABA-A; D001569:Benzodiazepines; D005442:Flumazenil