6-BROMO-2H-1,4-BENZOXAZIN-3(4H)-ONE

Uses

6-Bromo-2H-1,4-benzoxazin-3(4H)-one is used in the synthesis of substituted benzoxazinones; selective 5-HT6 antagonists used for treating central nervous system diseases and gastrointestinal tract disorders.

Uses

Building block used in the construction of pyrimidinyl substituted benzoxazinones, small molecule rennin inhibitors.

Synthesis

General procedure for the synthesis of 6-bromo-2H-1,4-benzoxazin-3(4H)-one from 2-amino-4-bromophenol and chloroacetyl chloride: triethylamine (TEA, 4.06 g, 40 mmol) was added to a tetrahydrofuran (THF, 150 mL) solution of 2-amino-4-bromophenol (5 g, 27 mmol). Subsequently, chloroacetyl chloride (3.33 g, 30 mmol) was added in batches at 0 °C. After 20 min of reaction, the mixture was continued to be stirred for 2 h at room temperature. The reaction mixture was again cooled to 0 °C and sodium hydride (NaH, 60% dispersed in mineral oil, 2.2 g, 54 mmol) was added in batches. After stirring at 0 °C for 20 min, the reaction mixture was brought to room temperature and stirring was continued for 2 h. The reaction mixture was then quenched with water. After completion of the reaction, the reaction was quenched with water. The solvent was removed by distillation under reduced pressure and the resulting residue was diluted with water. The precipitate was collected by filtration, washed with water and dried under vacuum to afford 6-bromo-2H-1,4-benzoxazin-3(4H)-one (5.5 g, 89% yield).

References

[1] Journal of Medicinal Chemistry, 2015, vol. 58, # 1, p. 333 - 346
[2] Archiv der Pharmazie, 2018, vol. 351, # 5,
[3] Patent: WO2015/153683, 2015, A1. Location in patent: Paragraph 0936
[4] Bioorganic and Medicinal Chemistry, 2010, vol. 18, # 3, p. 1288 - 1296
[5] Patent: WO2008/44022, 2008, A1. Location in patent: Page/Page column 26-27