Carthamin, a natural red pigment derived from safflower, was discovered centuries ago and has been utilized in several industries such as dye, food coloring, and natural medicine industries. Although it has been used since Egyptian times, its structural features were only determined in the mid-1900s when pioneering studies were conducted to elucidate the carthamin structure and assign its stereochemistry. Reproducing the complex biosynthesis of carthamin has been a common research goal since then. However, this has been rendered complex because of the unstable precursors and low yields from the multiple steps involved in the synthesis. Herein, we report the total synthesis of carthamin via a four-step procedure using (S)-C-β-D-glucosylquinochalcone as the starting compound. The synthesis involves mild conditions, short reaction time, and readily available compounds. After de-O-methylation, condensation, oxidative decarboxylation, and saponification, carthamin was obtained in an overall yield of 9.5% through the proposed method.
(S)‐4‐C‐β‐D‐Glucopyranosylquinochalcone, which is common to all yellow and red pigments of safflower petals, was synthesized as its stable methyl ether acetate in an overall yield of 3.6% via S‐diastereoselective oxidation of 3‐C‐(per‐O‐acetyl‐β‐D‐glucopyranosyl) phloroacetophenone using bis[(trifluoroacetoxy)iodo] benzene. This synthetic route is different from the previous one, including an oxidative dearomatization of the aryl C‐glycoside.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.