[C:1]([O:5][C:6]([NH:8][C@@H:9]1[CH2:18][CH2:17][C:16]2[C:11](=[CH:12][C:13]([OH:19])=[CH:14][CH:15]=2)[CH2:10]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].C(=O)([O-])[O-].[K+].[K+].Br[CH2:27][C:28]([O:30][CH2:31][CH3:32])=[O:29]>CC(C)=O>[C:1]([O:5][C:6]([NH:8][C@@H:9]1[CH2:18][CH2:17][C:16]2[C:11](=[CH:12][C:13]([O:19][CH2:27][C:28]([O:30][CH2:31][CH3:32])=[O:29])=[CH:14][CH:15]=2)[CH2:10]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]A solution of 10.8 g of (R)-2-tert-butoxycarbonylamino-7-hydroxytetraline (a) in 300 ml of acetone, is heated at reflux under stirring for 6 hours in the presence of 12.4 g of powdered anhydrous potassium carbonate and 15.1 g of ethyl bromoacetate. After filtration, acetone is evaporated under reduce pressure and the residue is taken up with ethyl ether. The solution so obtained is washed with water, dried over sodium sulfate and evaporated to dryness. The residue is taken up with ethyl ether and crystallized from isopropyl ether. Thus, 4.8 g of (R)-2-tert-butoxycarbonylamino-7-carbethoxymethoxytetraline are obtained; m.p. 113°-115° C., /alpha/=+57.97° (methanol, c=1%).
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