Structure Elucidation of a Pyrazolo[3,4]pyran Derivative by NMR Spectroscopy

Xuehui Liu,Yuxin Cui

doi:10.3390/12051117

Abstract

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.

Highlights

Recent advances in chemical biology have prompted a need for reliable methods and strategies for combinatorial synthesis of abundant small molecule libraries, which can be used to elucidate the function of proteins [1]
We have analyzed the configuration of a representative compound with 1D- and 2D-NMR spectroscopy and our results showed that the 6-member ring product was the dominant product of the palladium-catalyzed reaction between compound A and aryl iodides
By using HSQC and HMBC spectra combined with analysis of the 13C-NMR line shapes and the predicted chemical shifts obtained using the ChemOffice software package, complete proton and carbon assignments were made and long-range connectivity determined from the HMBC data (Table 1)

Summary

Introduction

Recent advances in chemical biology have prompted a need for reliable methods and strategies for combinatorial synthesis of abundant small molecule libraries, which can be used to elucidate the function of proteins [1]. The final step of the synthetic method involved a palladium-catalyzed cyclization, but under the reaction conditions more than one product was possible (Figure 1). By using HSQC and HMBC spectra combined with analysis of the 13C-NMR line shapes and the predicted chemical shifts obtained using the ChemOffice software package, complete proton and carbon assignments were made and long-range connectivity determined from the HMBC data (Table 1).

Results

Conclusion