Dan Zhang, An-jun Deng, Lin Ma
Jun 1, 2015
Citations
0
Influential Citations
2
Citations
Journal
Phytochemistry Letters
Abstract
Abstract Five new N -mono-/bis-substituted acetamide glycosides, N -{4- O -[3- O -(4- O -α- l -rhamnopyranosyl-β- d -glucopyranosyl)-α- l -rhamnopyranosyl]-phenethyl}-acetamide ( 1 ), N -methyl- N -{4- O -[3- O -(4- O -α- l -rhamnopyranosyl-β- d -glucopyranosyl)-α- l -rhamnopyranosyl]-phenethyl}-acetamide ( 2 ), N -methyl- N -{4- O -[3- O -(6- O -benzoyl-4- O -α- l -rhamnopyranosyl-β- d -glucopyranosyl)-α- l -rhamnopyranosyl]-phenethyl}-acetamide ( 3 ), N -methyl- N -{4- O -[3- O -(6- O -benzoyl-β- d -glucopyranosyl)-α- l -rhamnopyranosyl]-phenethyl}-acetamide ( 4 ), and N -methyl -N -{4- O -[3- O -(6- O - trans -cinnamoyl-4- O -α- l -rhamnopyranosyl-β- d -glucopyranosyl)-α- l -rhamnopyranosyl]-phenethyl}-acetamide ( 5 ), along with one known acetamide derivative, N -methyl- N -(4-hydroxyphenethyl)-acetamide, the shared aglycone of 2 – 5 , were isolated from the ethanol extract of the stems of Ephedra sinica . The structures of these new compounds were elucidated on the basis of extensive spectroscopic examination, mainly including multiple 1D and 2D NMR and HRESIMS examinations, and qualitative chemical tests. All N , N -bissubstituted acetamide glycosides were found to show the obvious rotamerism, as in the case of the isolated known N -methyl- N -(4-hydroxyphenethyl)-acetamide, under the experimental NMR conditions, with the ratios of integrated intensities between anti - and syn -rotamers always being found to be about 4 to 3.