反应详情

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%).

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