Synthesis of C-ring hydrogenated sinomenine cinnamate derivatives via Heck reactions

Abstract

The synthesis of C-ring hydrogenated sinomenine derivatives is accomplished from sinomenine by treatment with Zn-Hg/HCl, halogenation with NIS, and Heck reactions with various acrylates. A total of nine novel sinomenine cinnamate derivatives are obtained in 84%–93% yields. The structures of all the derivatives are characterized by 1H NMR, 13C NMR, and MS spectroscopy.

The present and future synthetic strategies of structural modifications of sinomenine

“…15,16 In the absence of the enone moiety, the iodination of C-ring non-functionalized derivatives also provided iodide 4 with a comparable yield (84%). 17 Halogenations using NXS also worked well in other substrates with 1,2-and 1,4-reduced enone of the C-ring. 16 Only monohalogenated products were observed when using NXS as the halogenating reagent.…”

“…Catalytic cross-coupling reactions of aryl iodide 4 with various acrylates and Pd(OAc) 2 by the Heck reaction generated cinnamate derivatives 9a-e with high yields (84-93%, Scheme 4). 17 Using a microreactor for the Heck reaction provided the same products 9f-j with higher yields by 46-68% in a short reaction time (20 min). 24 Generally, palladium-catalyzed cross-coupling reactions afforded (E)-isomers of adducts as the major products because the syn-β-hydride elimination of the reaction occurred via the less steric congestion to afford the thermodynamically favourable (E)-olefin.…”

“…61 Further reduction of the C-ring yielded 58 in one-pot from 1 with a high yield (81%) via the Clemmensen reduction of the in situ generated diketone 57 from hydrolysis (Scheme 24). 17 A small amount of two incomplete reduction products was also reported with either one ketone or one hydroxy group left in the C-ring, but the actual structural configurations were not determined.…”

Analysis of hygroscopicity and pyrolysis behaviour of propanediol esters synthesized by the enzymatic method

“…In the synthesis of esters, traditional chemical methods had high yields while polluting the environment 16 . In contrast, the use of recyclable and reusable lipases as catalysts for the synthesis of esters was in line with the green safety theme as well as sustainable production 17 .…”

“…14,15 In the synthesis of esters, traditional chemical methods had high yields while polluting the environment. 16 In contrast, the use of recyclable and reusable lipases as catalysts for the synthesis of esters was in line with the green safety theme as well as sustainable production. 17 Therefore, in this study, the synthesis of flavour molecular compounds with hydroxyl groups was carried out using Novozym 435 as a catalyst and transesterification reaction of propanediol with vinyl benzoate and vinyl cinnamate.…”