Acetic Acid → (5-Methoxy-1,2,3,4-tetrahydro-naphthalen-2-yl)-dimethyl-amine

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Reaction Steps

To a solution of 5-methoxy-2-tetralone (10.33 g, 58.62 mmol) dissolved in CH2Cl2 (400 mL) were added dimethylamine (5.6 M in EtOH, 14 mL, 76.206 mmol) and AcOH (0.46 mL, 5.862 mmol), and the mixture was stirred for 4 h at room temperature. It was then cooled to 0° C. and NaB(OAc)3H (0.45 eq, 5.59 g, 26.379 mmol) was added over a period of 20 min. After 1 h stirring at 0° C., NaB(OAc)3H (1.0 eq, 12.42 g, 58.62 mmol) was added over a period of 30 min. The reaction mixture was warmed to room temperature and stirred for 16 h. The mixture was cooled again to 0° C., and H2O (250 mL) was added slowly. The pH of the solution was adjusted to 8.0 by adding NaHCO3 saturated aqueous solution, and the mixture was stirred at 0° C. for 15 min. The layers were separated, and the aqueous phase was extracted with CH2Cl2 (4×100 mL). All organic phases were combined, dried over anhydrous Na2SO4 and concentrated in vacuo. The residue (12.51 g) was purified by flash chromatography on silica gel (1:100:1-100:0:1 AcOEt/Hexane/Et3N) affording 8.86 g of the title compound (Rf=0.5 (AcOEt/Hexane/Et3N 10:10:2), brown colored oil, 74% yield).

Provenance & Evidence