Formaldehyde → 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-1N aqueous hydrochloric acid mixture. The aqueous layer was extracted with chloroform and the chloroform extract discarded. The aqueous layer was then made basic with 14N 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 1N 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