Acetic Acid → 7-methoxy-N-propyl-1,2,3,4-tetrahydronaphthalen-2-amine

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Reaction Steps

A solution of 7-methoxy-2-tetralone (32 mmol. 5 g), n-propylamine (60 mmol. 5 mL), acetic acid (60 mmol. 4 mL), molecular sieves 3A (5 g) in ethanol (25 mL) was stirred at room temperature for 2.5 hrs. The solution was filtered on paper in a Paar bottle and the reduction was carried out with PtO2 (100 mg) as the catalyst, under 30 PSI of hydrogen. When the pressure dropped to 6 PSI (30 min.), the catalyst was removed by elution onto a column (celite 545) with chloroform. The eluent was concentrated under vacuum. The residue, a brown oil, was converted to solid by formation of hydrogen chloride salt in ether/HCl. Several recrystallizations in ether/methanol (60/40) afforded the final product (1) as white crystals (4.28 g, 61% yield).

Provenance & Evidence