Lithium hydroxide, monohydrate → 3,4-dihydro-2H-1,4-benzoxazine-8-carboxylic acid

HRID 912426Notes

Reaction equation

HRID 912426 reaction equation
C([O:3][C:4]([C:6]1[C:11]2[O:12][CH2:13][CH2:14][NH:15][C:10]=2[CH:9]=[CH:8][CH:7]=1)=[O:5])C.O.[OH-].[Li+]>O1CCCC1>[O:12]1[CH2:13][CH2:14][NH:15][C:10]2[CH:9]=[CH:8][CH:7]=[C:6]([C:4]([OH:5])=[O:3])[C:11]1=2

Participants

4

Reactant 2

HCID 168937Lithium hydroxide, monohydrateHCID 10584444HCID 10584444, compound

Product 1

HCID 534038413,4-dihydro-2H-1,4-benzoxazine-8-carboxylic acidYield 89.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 3,4-dihydro-2H-benzo[b][1,4]oxazine-8-carboxylic acid ethyl ester 2.1 g (10 mmol) of step 3 in a mixture of tetrahydrofuran 10 mL and distilled water 10 mL was added lithium hydroxide monohydrate 0.85 g (20 mmol), followed by stirring at room temperature for 8 hrs. After concentrating the reaction mixture in a vacuum, the reaction mixture was diluted with ethylacetate, washed with 1N HCl and a saturated NaCl solution, and dried over magnesium sulfate. The residue was concentrated in a vacuum and crystallized in ethylacetate/hexane to obtain 1.6 g of the title compound (yield 89%).

Workup

  1. distillationdistilled water 10 mL
  2. concentrationAfter concentrating the reaction mixture in a vacuum
  3. additionthe reaction mixture was diluted with ethylacetate
  4. washwashed with 1N HCl
  5. dry with materiala saturated NaCl solution, and dried over magnesium sulfate
  6. concentrationThe residue was concentrated in a vacuum
  7. customcrystallized in ethylacetate/hexane

Sources & evidence

ORD record
ord-d151ad9801124636982572f60fb4f2b3
Source dataset
uspto-grants-2011_09
Patent number
US08026235B1

Reaction notes

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