Heterocyclic Tautomerism. The Solution and Crystal Structures of 1-(4',6'-Dimethylpyrimidin-2'-yl)-3-methylpyrazol-5-ol

Abstract

Both in the solid state and in solution, the title compound is shown to exist as the OH tautomer (3), which is stabilized by a strong intramolecular hydrogen bond. Crystals of the pyrazol-5-ol (3) are monoclinic: P 2₁/c, a 9.692(5), b 7.371(5), c 15.345(8) Å, β 106.07(4)º, Z 4; the structure was refined to R 0.072 and R_w 0.062.