[NH2:1][C@@H:2]1[CH2:7][C:6]2[C:8]([O:13][CH3:14])=[CH:9][CH:10]=[C:11]([Br:12])[C:5]=2[O:4][CH2:3]1.[CH2:15](Br)[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.C(=O)([O-])[O-].[K+].[K+]>C(#N)C>[Br:12][C:11]1[C:5]2[O:4][CH2:3][C@H:2]([N:1]([CH2:7][C:6]3[CH:8]=[CH:9][CH:10]=[CH:11][CH:5]=3)[CH2:15][C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)[CH2:7][C:6]=2[C:8]([O:13][CH3:14])=[CH:9][CH:10]=1(R)-3-Amino-8-bromo-5-methoxy-3,4-dihydro-2H-1-benzopyran (11.5 g, 44 mmol) was dissolved in 400 mL anhydrous acetonitrile and to the reaction were benzyl bromide (13 mL, 110 mmol), anhydrous potassium carbonate (grounded) (16 g, 116 mmol), and a catalytic amount of KI added and then heated to 85° C. for 48 h. The solvent was removed in vacuo, the remains were taken into a 2M solution of NH3 and then extracted twice with ether. The combined ether portions were treated with brine, dried (MgSO4), filtered, and the solvent removed in vacuo to give the crude residue. Chromatography on silica (eluent: CH2Cl2) gave 15 g (78% yield) of the title compound as a clear oil. [α]21D =-15.5° (C=0.1 CHCl3) GC-MS (70eV) M=437 (15%).
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