Synthese von 5-Azido-3-nitro-ω-brom-acetophenon — einem photoaktivierbaren bifunktionellen Reagenz zur Vernetzung von Biopolymeren / Synthesis of 5-Azido-3-nitro-ω-bromo-acetophenone — a Photochemically Active Bifunctional Reagent for the Cross-Linking of Biopolymers
The photochemically activatable heterobifunctional reagent 5-azido-3-nitro-ω-bromo-acetophenone (3) was synthesized by condensation of 3,5-dinitrobenzoyl chloride with diethyl malonate, acid-catalyzed decarboxylation of the formed malonester derivative 1 to 3,5-dinitro-acetophenone (2a), selective reduction of one nitro group in 2a to 5-amino-3-nitro-acetophenone (2b) and diazotization to 2c. Nucleophilic displacement of the diazonium group in 2c by sodium azide forms 5-azido-3-nitro-acetophenone (2d) which gives 3 after bromination. Compound 3 is photochemically labile and forms an highly reactive nitrene during ultraviolet irradiation. Since compound 3 is able to alkylate amino-or mercapto-groups of amino acids or nucleosides via its bromoacetyl residue, the bifunctional reagent 3 should cross link proteins or nucleic acids after nitrene generation.