Adamantylazoles. 5. The molecular structure of 1-(1-adamantyl)pyrazoles

The crystal structures of 1-(1-adamantyl)-3,5-dimethylpyrazole 1 and 1-(1-adamantyl)-3,4,5-trimethylpyrazole 2 were studied by X-ray analysis. The space groups and cell parameters are: 1 , Cc, 13.4452(4), 14.9407(4), 7.1119(2) Å, 90, 111.944(2), 90°, with Z = 4. 2, P2₁/c, 6.7466(1), 21.2565(7), 10.1462(2) Å, 90, 106.368(2), 90°, with Z = 4. The final disagreement factors were 0.069 and 0.061, for 721 2σ(I)] and 1950 2σ(I)] observed reflexions, respectively. Compound 1 presents the adamantyl residue disordered between the two usual conformations. The experimental dipole moments and the carbon-13 chemical shifts (both in hexadeuteriodi-methylsulfoxide and in the solid state) were measured and discussed in connection with the structure of these compounds.