Lithium Hydroxide → 3-Oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylic acid

HRID 885683Notes

Reaction equation

HRID 885683 reaction equation
C[O:2][C:3]([C:5]1[CH:6]=[CH:7][C:8]2[O:13][CH2:12][C:11](=[O:14])[NH:10][C:9]=2[CH:15]=1)=[O:4].[Li+].[OH-]>C1COCC1.O>[O:14]=[C:11]1[NH:10][C:9]2[CH:15]=[C:5]([C:3]([OH:4])=[O:2])[CH:6]=[CH:7][C:8]=2[O:13][CH2:12]1

Participants

4

Reactant 2

HCID 3939Lithium HydroxideHCID 2974054Methyl 3-oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate

Product 1

HCID 7061213-Oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylic acidYield 260.6%

Reagents, catalysts & solvents 1

HCID 21881883Oxolane--water (1/1)Solvent

Procedure

To a solution of 3-oxo-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid methyl ester (3.13 g, 15.1 mmol) in THF/H2O (3:1; 76 mL) was added a LiOH (4 M in H2O; 19.0 mL, 75.5 mmol), and the solution was stirred at RT for 24 h. The solution was concentrated, diluted with H2O (50 mL), and acidified to pH<1 with conc. HCl. The resulting precipitate was collected by filtration afforded 7.6 g of the title compound contaminated with excess HCl and H2O. MS (ESI): exact mass calculated for C6H7NO4, 193.04; m/z found, 194.2 [M+H]+. 1H NMR (500 MHz, DMSO-d6): 10.85 (br s, 1H), 7.50-7.47 (m, 2H), 6.99 (d, J=8.3, 1H), 4.63 (s, 2H).

Workup

  1. concentrationThe solution was concentrated
  2. additiondiluted with H2O (50 mL)
  3. filtrationThe resulting precipitate was collected by filtration

Sources & evidence

ORD record
ord-a5061655144143bbb027c3488933b6e4
Source dataset
uspto-grants-2012_08
Patent number
US08242275B2

Reaction notes

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