Fumaric Acid → (S)-2-(4,4,7-trimethyl-1,4-dihydro-indeno[2,1-c]pyrazol-1-yl)-1-methyl-ethylamine fumarate

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Reaction Steps

0.7 g (2.5 mmol) of (S)-1-(2-azido-propyl)-4,4,7-trimethyl-1,4-dihydro-indeno[2,1-c]pyrazole dissolved in 50 ml of anhydrous methanol was hydrogenated over 70 mg of platinum oxide for 2 hours. The catalyst was subsequently filtered off, rinsed with ethanol and the solvent was removed in a vacuum. The colorless oil obtained was dissolved in 70 ml of anhydrous diethyl ether, filtered and treated while stirring with a solution of 290 mg (2.5 mmol) of fumaric acid in 5 ml of methanol. The mixture was stirred at room temperature for 4 hours and the white crystals were subsequently filtered off. 0.5 g (54%) of (S)-2-(4,4,7-trimethyl-1,4-dihydro-indeno[2,1-c]pyrazol-1-yl)-1-methyl-ethylamine fumarate (1:1) with m.p. 158° was obtained.

Provenance & Evidence