Aluminium lithium hydride → (9aR)-8-(phenylmethyl)octahydropyrazino[2,1-c][1,4]oxazine

Temperature

70 °C

To a 0° C. solution of (9aR)-8-(phenylmethyl)hexahydropyrazino[2,1-c][1,4]oxazine-6,7-dione (2.5610 g, 9.84 mmol) in THF (100 mL) was added LiAlH4 (1.12 g, 29.51 mmol) portionwise. The mixture was heated at 70° C. and stirred for 1 week. The mixture was then cooled to 0° C. and quenched by addition of Na2SO4.10H2O (2 g) followed by 1 N aq. NaOH (100 mL). The mixture was extracted with Et2O (2×150 mL), and the combined organic phase was dried over anhydrous Na2SO4, filtered, and concentrated in vacuo. The residue was dissolved in DCM (200 mL), dried over anhydrous Na2SO4, filtered, and concentrated in vacuo. The residue was purified by gradient silica gel chromatography (0% to 100% EtOAc in hexanes; 1% Et3N) to give (9aR)-8-(phenylmethyl)octahydropyrazino[2,1-c][1,4]oxazine (1.8147 g, 79%) as a colorless oil. LCMS: (M+H)+: 233.1.

1. temperatureThe mixture was then cooled to 0° C.
2. customquenched by addition of Na2SO4.10H2O (2 g)
3. extractionThe mixture was extracted with Et2O (2×150 mL)
4. dry with materialthe combined organic phase was dried over anhydrous Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. dissolutionThe residue was dissolved in DCM (200 mL)
8. dry with materialdried over anhydrous Na2SO4
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customThe residue was purified by gradient silica gel chromatography (0% to 100% EtOAc in hexanes; 1% Et3N)

ORD record

ord-00cf88791bd042e598db8824ca7b058d

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07893056B2