Configurational Analysis of Thebaine, Codeine and 14β-HydroxycodeinoneN-Oxides

The observed and calculated 1H and 13C chemical shifts of tertiary amines and their N‐oxides

“…In the early years of NMR when the configuration of chiral N ‐oxides was determined by chemical evidence7 or X‐ray,8 the effect of the N‐O group in amine N ‐oxides was observed for the first time in 1 H NMR. The reports dealing with the configuration determination of chiral N ‐oxides by NMR spectroscopy are mainly based on nuclear Overhauser effect (NOE) contacts of alkyl substituents on the nitrogen atom with other parts of the molecule 1, 9–12. The 1 J C, C coupling constants were also used for the discrimination of N ‐epimeric amine oxides 13…”

Development of chromatographic methods for thebaine detection and quantification along with some of related alkaloid derivatives

“…Various analytical methods have been reported and published which refer to thebaine or other alkaloid analysis and determination from Papaver plants like somniferum or bracteatum [7][8][9][10][11][12][13]. For instance, there are published methods for determination of alkaloids in Papaver somniferum and thebaine using HPLC with chemiluminescence detection [14][15][16], capillary electrophoresis analysis [17,18], infrared and Raman spectroscopy of alkaloids [19], infrared and ultraviolet spectroscopic determination [20] and configurational analysis of thebaine [21]. There are also other methods described in the literature, such as oxidative colorimetric analysis [22], determination of opiates by circular dichroism [23], colorimetric determination [24], TLC analysis of opiate alkaloids and drugs [25,26], ELISA (enzyme-linked immunosorbent assay) analysis of thebaine [27], FTIR spectroscopy of opiates and chemometric analysis [28], differential pulse polarography [29] and even a voltammetric analysis of thebaine [30].…”

13C GIAO DFT calculation as a tool for configuration prediction of N–O group in saturated heterocyclic N‐oxides

“…The reports dealing with the configuration determination of chiral N ‐oxides by NMR spectroscopy are mainly based on NOE contacts of alkyl substituents on the nitrogen atom with other parts of the molecule . The 1 J C,C coupling constants were also used for the discrimination of N ‐epimeric amine oxides .…”

“…[17] The reports dealing with the configuration determination of chiral N-oxides by NMR spectroscopy are mainly based on NOE contacts of alkyl substituents on the nitrogen atom with other parts of the molecule. [7,[19][20][21][22] The 1 J C,C coupling constants were also used for the discrimination of N-epimeric amine oxides. [23] In addition to that, the N-oxide configuration has been successfully established using predicted 13 C chemical shifts according to the multilinear regression analysis of chemical shifts differences of amine oxides and parent amines.…”