8-FLUORO-2H-BENZO[B][1,4]OXAZIN-3(4H)-ONE synthesis

3synthesis methods

Product Name:8-FLUORO-2H-BENZO[B][1,4]OXAZIN-3(4H)-ONE
CAS Number:560082-51-1
Molecular formula:C8H6FNO2
Molecular Weight:167.14

Acetic acid, 2-(2-fluoro-6-nitrophenoxy)-, methyl ester

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8-FLUORO-2H-BENZO[B][1,4]OXAZIN-3(4H)-ONE

560082-51-1
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Yield:560082-51-1 82%

Reaction Conditions:

Stage #1: (2-fluoro-6-nitrophenoxy)acetic acid, methyl esterwith iron;acetic acid at 20;
Stage #2: with sodium hydrogencarbonate;sodium hydroxide pH=7;

Steps:

Intermediate 7: 8-Fluoro-4H-benzo[l,4]oxazin-3-oneA stirred mixture of (2-fluoro-6-nitrophenoxy)acetic acid, methyl ester (1.44g, 0.0073mol) and iron powder (2.44g, 0.0438mol) in acetic acid (50mL) was stirred at room temperature overnight. The pH of the reaction mixture was adjusted to 7 by using sodium bicarbonate and sodium hydroxide solutions. The mixture was diluted with ethyl acetate. Water was added and the mixture was extracted with dichloromethane. The organic phase was dried (MgS0₄) and the solvent removed under reduced pressure. The residue was triturated with diethyl ether to afford 8- fluoro-4H-benzo[ l,4]oxazin-3-one as a yellow solid (l .Og, 82%).NMR: 5_H (^-DMSO) 4.63 (2H, s), 6.70 (1H, d), 6.88 (2H, m) and 10.88 (1H, br s).

References:

WO2011/144578,2011,A1 Location in patent:Page/Page column 29; 30

53981-25-2 Synthesis