Fluoroalkyl ethers (4) of dihydroartemisinin (2) have been prepared by reaction of fluoroalkyl alcohols with dihydroartemisinin by different methods (BF3,Et2O or TMSCl catalysis or Mitsunobu reaction). Ethers 4a-d derived from primary fluoroalkyl alcohols were obtained in moderate to good yields by these methods. Ethers 4e-j have been prepared from fluoroalkyl secondary and tertiary alcohols and phenol using the Mitsunobu reaction. Although in vitro antimalarial activities of ethers toward Plasmodium falciparum W-2 asiatic strain are moderate, in vivo activities against Plasmodium berghei (NT 173) are excellent.
[EN] METHOD FOR CULTURING HEMATOPOIETIC STEM CELLS<br/>[FR] PROCÉDÉ DE CULTURE DE CELLULES SOUCHES HÉMATOPOÏÉTIQUES<br/>[JA] 造血幹細胞の培養方法
C-10 Ester and Ether Derivatives of Dihydroartemisinin − 10-α Artesunate, Preparation of Authentic 10-β Artesunate, and of Other Ester and Ether Derivatives Bearing Potential Aromatic Intercalating Groups at C-10
作者:Richard K. Haynes、Ho-Wai Chan、Man-Ki Cheung、Wai-Lun Lam、May-Kei Soo、Hing-Wo Tsang、Arnd Voerste、Ian D. Williams
providing new C-10 ester and ether derivatives of the antimalarial drug dihydroartemisinin (DHA, 2) have been examined. β-Artesunate has been prepared for the first time, and has been differentiated from the antimalarial α-artesunate; the latter has been incorrectly designated as the β-epimer in Chemical Abstracts and some primary literature. New ester and ether derivatives bearing potential intercalating