title: Applying green chemistry to the photochemical route to artemisinin.
abstract: Artemisinin is an important antimalarial drug, but, at present, the environmental and economic costs of its semi-synthetic production are relatively high. Most of these costs lie in the final chemical steps, which follow a complex acid- and photo-catalysed route with oxygenation by both singlet and triplet oxygen. We demonstrate that applying the principles of green chemistry can lead to innovative strategies that avoid many of the problems in current photochemical processes. The first strategy combines the use of liquid CO2 as solvent and a dual-function solid acid/photocatalyst. The second strategy is an ambient-temperature reaction in aqueous mixtures of organic solvents, where the only inputs are dihydroartemisinic acid, O2 and light, and the output is pure, crystalline artemisinin. Everything else-solvents, photocatalyst and aqueous acid-can be recycled. Some aspects developed here through green chemistry are likely to have wider application in photochemistry and other reactions.
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Zacharias
authors.initials: Z
authors.lastname: Amara
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Jessica F B
authors.initials: JF
authors.lastname: Bellamy
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Raphael
authors.initials: R
authors.lastname: Horvath
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Miller
authors.affiliation: Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby
authors.affiliation: Sanofi-Aventis Deutschland GMBH, C&BD Frankfurt Chemistry, Process Research, Industriepark Hoechst, Frankfurt am Main D-65926, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Burgard
authors.affiliation: Sanofi-Aventis Deutschland GMBH, C&BD Frankfurt Chemistry, Process Research, Industriepark Hoechst, Frankfurt am Main D-65926, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Rossen
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Martyn
authors.initials: M
authors.lastname: Poliakoff
authors.affiliation: 1] School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK [2] Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, 199 Talking East Road, Ningbo 315100, China.
authors.forename: Michael W
authors.initials: MW
authors.lastname: George
mesh_terms: D037621:Artemisinins / Q000138:chemical synthesis*; D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D055668:Photochemical Processes
chemical_list: D037621:Artemisinins; D002245:Carbon Dioxide; C031327:artemisinin