2,5-Dibromoterephthalic acid → 2,5-Dibromo-4-(2,3-dihydro-pyrido[4,3-b][1,4]oxazin-4-carbonyl)-benzoic acid

Beteiligte Stoffe

Reaktionsschritte

In a 20 ml flask, 2,5-dibromo-terephthalic acid (100 mg, 0.31 mmol) and N,N-dimethyl formamide (3 drops) were dissolved in thionyl chloride (2 ml). After stirring for 2 hours at 800, the reaction mixture was cooled to room temperature and concentrated. Crude 2,5-dibromo-terephthaloic dichloride (112 mg, 0.31 mmol) was dissolved in dichloromethane (6 ml) and was added to 3,4-dihydro-2H-pyrido[4,3-b][1,4]oxazine (20.9 mg, 0.15 mmol) dissolved in dichloromethane (1 ml). Triethylamine (3 drops) were slowly added thereto and stirred at room temperature for 16 hours. After completion of the reaction, the residue was purified by preparative LC/Mass to obtain the target compound 23, i.e., 2,5-dibromo-4-(2,3-dihydro-pyrido[4,3-b][1,4]oxazin-4-carbonyl)-benzoic acid, as white solid (23 mg, 5%).

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