[BH4-].[Na+].[O:3]=[C:4]1[CH2:7][C:6]2([CH2:11][CH2:10][N:9]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8]2)[CH2:5]1>CO>[OH:3][CH:4]1[CH2:5][C:6]2([CH2:11][CH2:10][N:9]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8]2)[CH2:7]10.89 g (23.57 mmoles) of sodium borohydride is added in portions at 0° C. to a solution of 3.54 g (15.71 mmoles) of tert-butyl 2-oxo-6-aza-spiro[3.4]octane-6-carboxylate (WO 9806720) diluted in 40 ml of methanol. The reaction mixture is stirred for 1 hr and 30 mins at ambient temperature. After evaporation of the solvent, water is added to the reaction mixture, the aqueous phase is separated, it is extracted several times with diethyl ether, and the combined organic phases are washed with a saturated aqueous solution of sodium chloride, they are dried over sodium sulphate and the filtrate is concentrated under reduced pressure. After evaporation of the solvent, 3.10 g of product are obtained in the form of a brown oil used as such in the following stage.
Wird geladen…