Structure elucidation of a pyrazolo[3,4]pyran derivative by NMR spectroscopy.

The structure of a representative pyrazolo[3,4]pyran derivative was determined by 1D and 2D NMR techniques. Complete 1H and 13C chemical shifts for this compound are reported. Careful analysis of the HMBC (Heteronuclear Multi-Bond Correlation) spectrum helped to elucidate the configuration of the derivative around C7 and C8. The results showed that the characteristic double-strong and double-weak cross peak pattern in the HMBC spectrum for C7 and C8 might be useful for establishing the structures of other pyrazolo[3,4]pyran derivatives.