Acetic Acid → 1-benzyl-N'-(1H-indol-3-ylmethyl)-N,N-dimethylcyclohexane-1,4-diamine dihydrochloride

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Reaction Steps

292 mg C-(1H-indol-3-yl)-methylamine were partly dissolved in dry 1,2-dichloroethane (10 ml) under argon. After addition of 463 mg 4-benzyl-4-dimethylamino-cyclohexanone (see example 3), glacial acetic acid (4 mmol) and sodium triacetoxyborohydride (550 mg), the suspension was stirred for 72 hours at room temperature. For working up, water (10 ml) was added to the reaction mixture. The organic phase was separated off and the aqueous phase was extracted twice with ether and then rendered strongly alkaline with sodium hydroxide solution. The mixture was extracted again with ethyl acetate (4×10 ml). A pale precipitate precipitated out of the combined ethyl acetate phases even during the processing. After cooling, this was filtered off with suction, washed twice with cold ethyl acetate and dried. The product obtained in this way (235 mg) was white and solid (m.p. 194-198° C.). 217 mg were dissolved hot in 2-butanone/ethanol (30+10 ml), and saturated ethanolic hydrochloric acid (1.5 ml; 1.85 M) was added at RT, while stirring. After two hours, no precipitate had yet precipitated out. Even after reducing the amount of solvent and cooling, no hydrochloride precipitated out. The mixture was therefore evaporated to dryness at 40° C. in vacuo and excess HCl was driven off. 260 mg 1-benzyl-N′-(1H-indol-3-ylmethyl)-N,N-dimethylcyclohexane-1,4-diamine dihydrochloride were obtained as the residue as a pale pink-colored solid of m.p. 170-174° C.

Provenance & Evidence