Ammonium Acetate → HCID 131712271, compound

Participants

Reaction Steps

In accordance with Reaction Scheme II, a 3-enol ether-6-hydroxymethylene-2-cyclohexenone, for example 3-ethoxy-6-hydroxymethylene-2-cyclohexenone, prepared by the method of Wenkert et al. J. Org. Chem., 27, 2278 (1962), is reacted with hydrazine hydrate in a mutual inert solvent such as ethanol to yield dl-6-ethoxy-4,5-dihydro-1H-indazole (VIII) and its 2H tautomer (VIIIa). Hydrolysis with acid, preferably a strong, highly ionized acid such as p-toluenesulfonic, trifluoroacetic, hydrochloric etc., yields dl-6-oxo-4,5,6,7-tetrahydro-1H-indazole (IX) and the 2H tautomer (IXa). Reductive amination of this oxo compound with ammonium acetate and sodium cyanoborohydride, or other suitable organometallic reducing agent of sufficient reducing power, in the presence of a mutual inert solvent yields the corresponding dl-6-amino-4,5,6,7-tetrahydro-1H-indazole, (X) and dl-6-amino-4,5,6,7-tetrahydro-2H-indazole, compounds coming within the scope of formulas I and II above wherein R is H and R1 is NH2.

Provenance & Evidence