Labeling of alprenolol with fluorescent aryl iodide as a reagent based on Mizoroki–Heck coupling reaction

Abstract

A novel fluorescent labeling method for alprenolol was developed based on Mizoroki-Heck coupling reaction. We designed and synthesized fluorescent aryl iodide, 4-(4,5-diphenyl-1H-imidazol-2-yl)iodobenzene (DIBI) as a labeling reagent.DIBI has a lophine skeleton carrying an iodide atom acting as fluorophore and reactive center, respectively. In order to evaluate the usefulness of DIBI, a highperformance liquid chromatography (HPLC) with fluorescence detection method was developed for the determination of alprenolol as a model compound of terminal double bond. The fluorescent labeling of alprenolol with DIBI was achieved in the presence of palladium acetate as a catalyst, and the labeled alprenolol was detected fluorometrically. In addition, it was found that the fluorescence of DIBI derivative increased and red shifted when compared that of DIBI. Furthermore, the proposed method could be applied to determine the alprenolol concentration in rat plasma after administration of alprenolol without interferences from biological components. The detection limit (S/N=3) for alprenolol in rat plasma was 0.74 ng/mL (30 fmol on column).

HPLC Fluorescence Method for Eugenols in Basil Products Derivatized with DIBI

“…Higashi reported an HPLC-FL method for the determination of Eug by pre-column derivatization with 4-(N-chloroformylmethyl-N-methylamino)-7-nitro-2,1,3-benzoxadiazole (NBD-COCl). 19) This reagent reacts with the phenolic component of Eug under mild conditions to allow high sensitivity detection. However, MeEug could not be detected, because it does not react with NBD-COCl.…”

“…The sensitivity of the proposed method was compared with those of the previous reports and the results are shown in Table 3. The proposed method is considered to be more sensitive than GC/MS methods, 8,9) HPLC-UV methods, [10][11][12] another HPLC-FL method using derivatization with NBD-COCl, 19) and an ELISA method. 16) Our method is comparable to the LC-MS/MS method for Eug, 15) but is less sensitive for MeEug.…”

A selective and highly sensitive high performance liquid chromatography with fluorescence derivatization approach based on Sonogashira coupling reaction for determination of ethinyl estradiol in river water samples

“…DIB-I was prepared in our laboratory according to the synthesis method previously reported [21]. Where p-iodobenzaldehyde (110 mg, 0.5 mmol), ammonium acetate (97 mg, 1.25 mmol) and benzil (53 mg, 0.25 mmol) were dissolved in 2.5 mL acetic acid.…”

“…EE has an ethinyl group that make it a good candidate for Sonogashira coupling reaction, and either other steroid hormones or co-existing phenolic compounds that may be present in environmental samples wouldn't interfere with its determination. Only EE is predicted to be capable of reacting with DIB-I reagent, a fluorescent labeling reagent prepared in our laboratory [21]. The selectivity of the proposed method was checked using estrone, a female sex hormone that possess a phenolic OH group in its structure but does not have an ethinyl group.…”

“…The fluorescent aryl halide labeling reagent used in this reaction is 4-(4,5diphenyl-1H-imidazol-2-yl) iodobenzene (DIB-I); a reagent prepared in our laboratory [26]. DIB-I is a lophine derivative having an iodide atom which act as a fluorophore and a reactive center, respectively [21]. The highly sensitive fluorescent product was measured at 400 nm (after excitation at 310 nm).…”