... Phytochemistry. Volume 68, Issue 5, March 2007, Pages 692–696. ... This functional group was located at C-4″ of the rhamnopyranosyl unit due to the downfield shift of C-4″ and the upfield shifts of C-3″ and C-5″ by +0.8, −1.7, and −1.8 ppm, respectively. ...