The Investigation of ¹H NMR Spectra of 2,3-Dihydro-4-Pyridinones Derived from Bisdemethoxycurcumin

Problem statement: The studied dihydropyridones were synthesized via microwave assisted reaction of bisdemethoxycurcumin and amines or amine acetates which is new approach in the synthesis of this important class of compounds and the deep study of their NMR spectra seems reasonable. Approach: ¹H NMR spectra of dihydropyridones derived from curcumin were discussed and their structures were elucidated accordingly. Results: The one dimentional, HOMO-and HETERO-COSY spectra indicated the presence of two doublets of doublets signals of two geminaly coupled protons with ²J values of 16 Hz. Both these protons coupled to the same vicinal proton within a six-membered ring with ³J coupling constants of 3J values of 7 and 4 Hz. Computational calculations using B3LYP/6-311+G(d,p)//B3LYP/6-31G(d,p) level of theory were undertaken to predict the chemical shifts of one molecule via the GIAO method. Conclusion: The above mentioned theoretical method affords good approach for the prediction of the NMR spectra of the studied compounds.