title: Chemical synthesis and some properties of 6-substituted flavins.
abstract: A number of derivatives of riboflavin and of 3-methyllumiflavin substituted in the 6 position have been synthesized starting with 6-nitro flavins, reduction to the 6-amino flavin, and diazotization, followed by reaction with the appropriate nucleophile. The absorption spectra, oxidation-reduction potentials, and the electron spin resonance spectra of the radical cationic forms of several of these synthetic compounds have been determined, including 6-S-cysteinyl-3-methyllumiflavin and 6-S-cysteinylriboflavin. The latter has been shown to be identical with the dephosphorylated form of the aminoacyl flavin isolated from trimethylamine dehydrogenase [Steenkamp, D. J., Kenney, W. C. & Singer, T. P. (1978) J. Biol. Chem. 253, 2812-2817; Steenkamp, D. J., McIntire, W., & Kenney, W. C. (1978) J. Biol. Chem. 253, 2818-2824] in regard to absorption specturm, photochemical properties, and mobility in high-voltage electrophoresis and in thin-layer chromatography. An unusually pronounced interaction between the amino group and the isoalloxazine ring system was deduced from the absorption spectra of 6-amino-3-methyllumiflavin and 6-aminoriboflavin.
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005415:Flavins / Q000138:chemical synthesis; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008722:Methods; D012256:Riboflavin / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D013053:Spectrophotometry; D013329:Structure-Activity Relationship
chemical_list: D005415:Flavins; D007202:Indicators and Reagents; C008465:3-methyllumiflavin; D012256:Riboflavin