Hydrochloric Acid → HCID 131712278, compound

Participants

Reaction Steps

A reaction mixture was prepared containing 630 mg. of dl-5-amino-4,5,6,7-tetrahydro-1H-indazole dihydrochloride and its 2H tautomer dihydrochloride 410 mg. of sodium acetate, and 75 ml. of ethanol. To this mixture was added 380 mg of sodium cyanoborohydride followed by 1 ml. of 37% aqueous formalin. The resulting mixture was stirred at ambient temperature for about 17 hours, after which time it was poured into an ice-1 N aqueous hydrochloric acid mixture. The aqueous layer was extracted with chloroform and the chloroform extract discarded. The aqueous layer was then made basic with 14 N aqueous ammonium hydroxide and the resulting alkaline solution extracted several times with a chloroform-isopropanol solvent mixture. The extracts were combined and the combined extracts washed with saturated aqueous sodium chloride and then dried. Evaporation of the solvent yielded 0.43 g. of a residue comprising dl-5-dimethylamino-4,5,6,7-tetrahydro-1H-indazole and dl-5-dimethylamino-4,5,6,7-tetrahydro-2H-indazole formed in the above reaction. NMR of the tautomeric mixture gave characteristic peaks at 142 cps (singlet-aminomethyl) 432 and 440 cps (broad singlet C-3H) using CDCl3. The compounds were further purified by dissolving the residue in 10 ml. of 1 N aqueous hydrochloric acid and diluting this mixture with anhydrous ethanol. This solution was evaporated to dryness in vacuo and the resulting residue crystallized from a methanol/ether solvent mixture. dl-5-Dimethylamino-4,5,6,7-tetrahydro-1H-indazole dihydrochloride and dl-5-dimethylamino-4,5,6,7-tetrahydro-2H-indazole dihydrochloride thus prepared melted at 230°-38° with foaming; yield=430 mg.

Provenance & Evidence