Biomimetic synthesis of nudicaulins I and II, yellow pigments from the Iceland poppyPapaver nudicaule

Abstract

We describe the biomimetic synthesis of nudicaulins I and II, yellow pigments from the Iceland poppy Papaver nudicaule.

Optimized Synthesis and Antioxidant Activity of Anthocyanins Delphinidin-3-O-glucoside and Petunidin-3-O-glucoside

“…Nevertheless, the extraction of pure anthocyanins from natural sources remains a formidable challenge. , Dp3G and Pt3G, with natural content below 12%, are particularly elusive. Chemical synthesis has emerged as an alternative, but existing pathways like aldol condensation, flavonoid reduction by metals, and biomimetic oxidation routes pose challenges like low efficiency, lengthy processes, high costs, and operational risks . The scarcity of reported synthesis methods contributes to the high market cost of pure anthocyanins, hindering research on their functionality …”

Selective Iodination Enables Anthocyanin Synthesis to Be More General

“…At the same time, it is noteworthy that the synthesis of 5-or 7-glucose-substituted anthocyanin remains under-reported. Sperry et al 20 developed a synthetic method to connect glucose to the para position of phloroglucinol aldehyde for nudicaulins synthesis. To selectively protect the ortho-hydroxyl, benzoyl chloride was employed and then glycosylated by glucopyranosyl bromide.…”

“…A ring synthesis of 3-glucose-substituted anthocyanins requires just 2,4,6-trihydroxy benzaldehyde with AC 2 O and DMAP refluxed in ethyl acetate to yield compound 3 (Scheme ). The A ring synthesis method of 3,7-anthocyanin diglucoside was according to the report of Sperry et al 2,4,6-Trihydroxy benzaldehyde and BzCl were stirred in potassium hydroxide solution at 0 °C to obtain ortho-protected compound 10 , and then it was coupled with 2,3,4,6-tetra- O -acetyl- d -glucopyranosyl bromide in an Ag 2 O suspension in quinoline at room temperature to give compound 4 (Scheme ). To synthesize the 3,5-anthocyanin diglucoside, we initially tried a method that protects the para-position of 2′,4′,6′-trihydroxyacetophenone .…”