Syntheses of novel series benzo [1,5] oxazepin-4-one-based compounds from 1,5-difluoro-2,4-dinitrobenzene

A novel benzo [1,5] oxazepin-4-one skeleton compound and its four derivatives were synthesized effectively from 1,5-difluoro-2,4-dinitrobenzene (DFDNB) under mild conditions. In the process, four intermediates were synthesized by substitutions of the two fluorine atoms and reductions of the meta-dinitro groups in DFDNB respectively. The results showed that the key for synthesizing the intermediates was the substitution of one of the two fluorine atoms in DFDNB by 3-hydroxy butyric acid ethyl ester first, then the other fluorine atom by morpholine, and then the reduction of the meta-dinitro groups in the substitute by HCOONH4 with Pd/C. The products were purified with silica gel column chromatography, and confirmed by HPLC, LC-MS and 1H NMR. They should contribute to construct the molecular libraries for therapeutic applications.