Acetic Acid → 8-Methoxy-2-(4-methylpiperazin-1-yl)-1,2,3,4-tetrahydronaphthalene

Participants

Reaction Steps

1.76 g (10 mmol) of 8-methoxy-2-tetralone, 3.00 g (30 mmol) of N-methylpiperazine and 1.80 g (30 mmol) of glacial acetic acid were refluxed in 30 ml of methanol for 4 hours. 1.30 g (20 mmol) of sodium cyanoborohydride were then added, and the mixture was refluxed for a further hour. The reaction mixture was substantially concentrated in a rotary evaporator, taken up in tert.-butyl methyl ether, and stirred vigorously for 30 minutes in 20% strength sodium hydroxide solution. The aqueous phase was extracted carefully with tert.-butyl methyl ether. Washing the combined organic phases with water and saturated sodium chloride solution, drying over potassium carbonate, and concentrating in a rotary evaporator yielded the crude product as an oil (2.9 g). This crude product was combined with that obtained from a batch of equal size (this reaction was carried out in the presence of 3A molecular sieve, otherwise the same) and chromatographed on silica gel (toluene/methanol 4:1). 4.20 g of the title compound were obtained in this fashion as a brownish oil (80%).

Provenance & Evidence