Water → 3-(2,5-Dibromovaleryl)amino-5,6,7,8-tetrahydro-2-naphthol

To a mixture of 3-amino-5,6,7,8-tetrahydro-2-naphthol hydrobromide (1.70 g), sodium hydrogencarbonate (1.46 g), ethyl acetate (15 ml) and water (10 ml) was added under ice-cooling while stirring a solution of 2,5-dibromovaleryl chloride (1.94 g) in ethyl acetate (6 ml). The whole mixture was stirred for further 30 minutes. The ethyl acetate layer was separated, and the aqueous layer was extracted with ethyl acetate. The combined ethyl acetate layer was washed with an aqueous saline. solution, then dried (MgSO4), followed by distilling off the solvent to obtain 3-(2,5-dibromovaleryl)amino-5,6,7,8-tetrahydro-2-naphthol. This compound was dissolved in dimethylformamide (20 ml). To the solution was added powdery potassium carbonate (1.2 g), and the mixture was stirred at room temperature for 1.5 hour. To the resultant was added water, and precipitated crystals were collected by filtration, washed with water and dried, followed by recrystallization from ethyl acetate to obtain 1.53 g (67.8%) of 2-(3-bromopropyl)-6,7,8,9-tetrahydro-2H-naphtho [2,3 -b][1,4]oxazin-3(4H)-one as crystals, m.p. 139°-140° C. This compound was found to be identical with the product obtained in Reference Example 7.

1. additionwas added under ice-
2. temperaturecooling
3. customThe ethyl acetate layer was separated
4. extractionthe aqueous layer was extracted with ethyl acetate
5. washThe combined ethyl acetate layer was washed with an aqueous saline
6. dry with materialsolution, then dried (MgSO4)
7. distillationby distilling off the solvent

ORD record

ord-94c8e9cae406469da81ed383fa1c9a35

Source dataset

uspto-grants-1988_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04789675