Heterocycles, 57, 307-316 (2002)

DOI: 10.3987/COM-01-9407

Synthesis, 1H and 13C NMR study of pyrazoles derived from chiral cyclohexanones (3-methylcyclohexanone, menthone, pulegone, dihydrocarvone and carvone)

The 1H and 13C chemical shifts of four tetrahydroindazoles (two of them existing as diastereomeric mixtures) and one aldazine were measured and assigned. These compounds were obtained from monoterpenic ketones (R)-(+)-3-methylcyclohexanone, (2S,5R)-(-)-menthone, (R)-(+)-pulegone, (5R)-(+)-dihydrocarvone, and (R)-(-)-carvone in a two-step procedure. The annular tautomerism in CDCl3solution was calculated and compared with ab initio calculations (B3LYP/6-31G*).