Characterisation, extraction efficiency, stability and antioxidant activity of phytonutrients in Angelica keiskei

Synthesis of Biologically Active Natural Component 4-Hydroxyderricin Through Water-Accelerated [3,3]-Sigmatropic Rearrangement

“…14 These results lead us to choose the method b, which involves the Claisen-Schmidt condensation of the two phenolic units 3 and 5 to chalcone 6 and the [3,3]sigmatropic rearrangement of 6 to install the m-prenyl unit for the synthesis of 4-hydroxyderricin.…”

“…7 Two types of polyphenolic chalcones, 4-hydroxyderricin (1) and xanthoangelol (2), are especially rich in the plant, and the 4-hydroxyderricin exhibited the major responsibility for the various biological activities. 10 Sugamoto reported the synthesis of 4-hydroxyderricin via [1,3]-sigmatropic rearrangement of chalcone ether using montmorillonite K10 which showed relatively low rearrangement yield (Scheme 1), and this is the only reported total synthesis of 1 as far as we know. 11 We recently developed the water-accelerated [3,3]-sigmatropic rearrangement reaction for licochalcone A synthesis 12 and showed advantages promising higher yield and preventive effect to abnormal rearrangement which was known disadvantage 13 of [3,3]-sigmatropic rearrangement reactions.…”

“…One is Claisen-Schmidt condensation of benzaldehyde 3 with acetophenone 4, which is derived from the [3,3]-sigmatropic rearrangement of acetophenone 5 to build chalcone structure (method a), and the other is [3,3]-sigmatropic rearrangement reaction of chalcone 6, which is derived from ClaisenSchmidt condensation of benzaldehyde 3 with acetophenone 5 (method b).…”

“…For example, the [3,3]sigmatropic rearrangement of aryl allyl ether 7 produced the expected product 8 in 40% yield along with a deprenylated product 9 (10%). However, the reaction of chalcone 10 yielded licochalcone A 11 in 86% yield without any side product (Scheme 3).…”

“…However, the reaction of chalcone 10 yielded licochalcone A 11 in 86% yield without any side product (Scheme 3). 12 In licochalcone D synthesis, the [3,3]sigmatropic rearrangement reaction of aryl allyl ether 12 produced the desired product 13 in 72% yield without any side product, and the conjugated aryl ether 14 also yielded licochalcone D directly without additional deprotection procedure in water-accelerated [3,3]-sigmatropic rearrangement Scheme 2. Retrosynthetic approach to 4-hydroxyderricin.…”