Photoredox reactions are placed in sequence with asymmetrictransferhydrogenations of aryl ketones to provide chiral alcohols with enantioselectivities of up to 99 % ee. The method relies on a single chiral‐at‐metal iridium catalyst which is added at the beginning of the two step sequence and only a final purification of the reaction product is required.
Antimalarial Activity of New Dihydroartemisinin Derivatives. 7. 4-(<i>p</i>-Substituted phenyl)-4(<i>R</i> or <i>S</i>)-[10(α or β)-dihydroartemisininoxy]butyric Acids<sup>1-6</sup>
作者:Ai J. Lin、Akram B. Zikry、Dennis E. Kyle
DOI:10.1021/jm9607919
日期:1997.4.1
or S)-[10(alpha or beta)-dihydroartemisininoxy]butyric acids were synthesized as new potential antimalarial agents. Two approaches were taken in the design of these new molecules in an attempt to (a) increase the lipophilicity of the molecule and (b) decrease the rate of oxidative dealkylation of the target compounds. The new compounds showed a 2-10-fold increase in in vitro antimalarial activity against
A compound represented by general formula (1) (wherein R
1
represents a hydrogen atom, an optionally substituted C
1-6
alkyl group or the like; R
2
represents a hydrogen atom, an optionally substituted C
1-6
alkyl group or the like; R
3
represents a hydrogen atom or an optionally substituted C
1-6
alkyl group; R
4
represents a hydrogen atom, an optionally substituted C
1-6
alkyl group or the like; X
1
represents an optionally substituted C
2-6
alkynylene group or the like; A represents an optionally substituted bivalent aromatic hydrocarbon group or the like; X
2
represents an optionally substituted C
1-6
alkylene group or the like; Y
1
represents an oxygen atom or the like; and R
5
represents a hydrogen atom or the like) or a salt thereof is useful as an antibacterial agent.