Multinuclear magnetic resonance spectroscopy allowed us to characterize four 1 (2), 5, 6, 7- tetrahydro-4H-indazol-4-one derivatives (1–4) and establish the most stable tautomer in each case. The crystal structure of 6, 6-dimethyl-1 (2), 5, 6, 7-tetrahydro-4H-indazol-4-one (2)(orthorhombic space group P2 (1) 2 (1) 2 (1), a= 10.1243 (8), b= 21.526 (2), c= 24.992 (2) Å, Z= 4, 293K) presents two different trimers, bonded through N–H⋯ N hydrogen bonds ...
