4.75 g mexamine and 4 g sodium carbonate were suspended in 20 mL acetonitrile in a 100 mL Erlenmeyer flask with a 40 mm stir bar. 16 g fresh methyl tosylate was dissolved in 20 mL acetonitrile and added to the flask. The flask was stoppered with an open stopcock adapter, the mixture was stirred for 9 hours at 50 °C and 500 rpm, cooled down, vacuum-filtered, washed thoroughly with 3 x 25 mL acetone and dried in air to yield 20.17 g white powder, presumably a mix of sodium carbonate, sodium tosylate, and N,N,N,O-tetramethylserotonin tosylate.
The powder was suspended in 25 mL ethanolamine in a two-neck 100 mL boiling flask flushed with argon and equipped with a stir bar, a thermometer adapter, and a gas intake-exhaust adapter connected to a gas bubbler. Under argon flow the suspension was stirred for 4.5 hours at 160 °C and cooled down to room temperature. The solidified reaction mixture was broken up with a spatula, dissolved with stirring and a bit of heating in 125 mL water, basified with 2 g potassium carbonate, and extracted with 3 x 20 mL N-amyl acetate using a 250 mL separatory funnel. The combined extracts were washed with 5 mL concentrated NaCl brine using a 125 mL separatory funnel and gravity-filtered into a 100 mL Erlenmeyer flask with 3 g benzoic acid. The mixture was stirred and heated up until precipitating benzoate salts redissolved, then slowly cooled down and kept in a refrigerator overnight. The crystals were filtered, powderized and washed thoroughly with heptane, dried in air to yield 6.05 g ivory powder, presumably 5-methoxy-N,N-dimethyltryptammonium benzoate (71% yield), melting point 123.6 °C.
The benzoate salt was suspended in 25 mL fairly concentrated aqueous NaOH (pH > 12) and vortexed for a minute with 50 mL heptane at the temperature over 75 °C in a 100 mL Erlenmeyer flask. The heptane was pipetted out, the hot extraction was repeated 3 more times (200 mL heptane in total). The combined extracts were evaporated to ~150 mL under a fan while stirring with some potassium carbonate, hot-filtered into an Erlenmeyer flask, reheated and slowly cooled down to refrigerator temperature. The solvent was decanted and the large white crystals on the bottom were dried in the same flask under vacuum to yield 5-methoxy-N,N-dimethyltryptamine, melting point 68.4 °C (lit. 69.5 °C).
The powder was suspended in 25 mL ethanolamine in a two-neck 100 mL boiling flask flushed with argon and equipped with a stir bar, a thermometer adapter, and a gas intake-exhaust adapter connected to a gas bubbler. Under argon flow the suspension was stirred for 4.5 hours at 160 °C and cooled down to room temperature. The solidified reaction mixture was broken up with a spatula, dissolved with stirring and a bit of heating in 125 mL water, basified with 2 g potassium carbonate, and extracted with 3 x 20 mL N-amyl acetate using a 250 mL separatory funnel. The combined extracts were washed with 5 mL concentrated NaCl brine using a 125 mL separatory funnel and gravity-filtered into a 100 mL Erlenmeyer flask with 3 g benzoic acid. The mixture was stirred and heated up until precipitating benzoate salts redissolved, then slowly cooled down and kept in a refrigerator overnight. The crystals were filtered, powderized and washed thoroughly with heptane, dried in air to yield 6.05 g ivory powder, presumably 5-methoxy-N,N-dimethyltryptammonium benzoate (71% yield), melting point 123.6 °C.
The benzoate salt was suspended in 25 mL fairly concentrated aqueous NaOH (pH > 12) and vortexed for a minute with 50 mL heptane at the temperature over 75 °C in a 100 mL Erlenmeyer flask. The heptane was pipetted out, the hot extraction was repeated 3 more times (200 mL heptane in total). The combined extracts were evaporated to ~150 mL under a fan while stirring with some potassium carbonate, hot-filtered into an Erlenmeyer flask, reheated and slowly cooled down to refrigerator temperature. The solvent was decanted and the large white crystals on the bottom were dried in the same flask under vacuum to yield 5-methoxy-N,N-dimethyltryptamine, melting point 68.4 °C (lit. 69.5 °C).
