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ChemicalBook CAS DataBase List 7-Fluoro-3,4-dihydro-2H-benzo[1,4]oxazine
56346-41-9

7-Fluoro-3,4-dihydro-2H-benzo[1,4]oxazine synthesis

4synthesis methods
-

Yield:56346-41-9 90%

Reaction Conditions:

with lithium aluminium tetrahydride in tetrahydrofuran at 0 - 23; for 4 h;

Steps:

19.b

Lithium aluminum hydride (1.2 g, 3.2 mmol) was carefully added in portions to a solution of 7-fluoro-2H-benzo[b][1,4]oxazin-3(4H)-one (3.5 g, 2.1 mmol) in THF (30 mL) at 0 °C. Once the addition was complete, the cooling bath was removed, and the mixture was stirred at ambient temperature for 4 h. After TLC analysis indicated complete reaction, the mixture was quenched using Fieser protocol and the product was extracted diethyl ether. After all solvent was removed under reduced pressure, the crude product was purified by column chromatography (SiO2, hexanes/EtOAc gradient) to produce 7-fluoro-3,4-dihydro-2H-bcnzo[b][1,4]oxazine (2.9 g, 18.9 mmol, 90% yield) as a brown solid. 1H NMR (400 MHz, CDCl3) δ 6.63 - 6.22 (m, 3H), 4.30 - 4.18 (m, 2H), 3.59 (s, 1H), 3.44 - 3.32 (m, 2H). 19F NMR (376 MHz, CDCl3) δ -124.56.

References:

WO2021/188769,2021,A1 Location in patent:Paragraph 0262; 0263

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