Sodium Sulfate → N-(4-Bromo-2-(2,2-dimethoxyethyl)phenyl)-8-methyl-8-azabicyclo[3.2.1]octan-3-amine

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Reaction Steps

Crude compound 67 (225.4 mg, 0.866 mmol) and 8-methyl-8-azabicyclo[3.2.1]octan-3-one (241.1 mg, 1.732 mmol) were stirred in acetic acid (10 mL) under argon in the presence of anhydrous sodium sulfate (1.230 g, 8.660 mmol) at room temperature for 30 minutes. Sodium triacetoxyborohydride (550.6 mg, 2.598 mmol) was then added and the mixture stirred for 24 hours at room temperature. After dilution with a mixture of 8:1 ethyl acetate:Hexanes, the reaction is quenched with saturated sodium bicarbonate. The mixture was transferred to a separatory funnel and the organic layer separated. The organic layer was dried over sodium sulfate and concentrated under reduced pressure and the residue purified via chromatography on silica gel (2M NH3 in methanol:CH2Cl2, 5:95%) to yield a pale yellow residue, 83 (120 mg, 36.1%) as an 5:1 or 1:5 mixture of endo/exo stereoisomers. 1H NMR (major isomer-DMSO-d6) δ 1.56-1.70 (m, 2H), 1.87-1.99 (m, 4H), 2.04-2.09 (m, 2H), 2.21 (s, 3H), 2.79 (d, 2H, J=5.3 Hz), 3.03-3.17 (m, 2H), 3.28 (s, 6H), 3.40-3.49 (m, 1H), 4.54 (t, 1H, J=5.3 Hz), 4.98 (s, 1H), 6.36 (d, 1H, J=9.3 Hz), 7.11-7.21 (m, 2H); ESI-MS (m/z, %): 383/385 (MH+, 100%).

Provenance & Evidence