Structure−Activity Relationships of the Antimalarial Agent Artemisinin. 7. Direct Modification of (+)-Artemisinin and In Vivo Antimalarial Screening of New, Potential Preclinical Antimalarial Candidates
作者:Mitchell A. Avery、Maria Alvim-Gaston、Jeffrey A. Vroman、Baogen Wu、Arba Ager、Wallace Peters、Brian L. Robinson、William Charman
DOI:10.1021/jm020142z
日期:2002.9.1
On the basis of earlier reported quantitative structure-activity relationship studies, a series of 9beta-16-(arylalkyl)-10-deoxoartemisinins were proposed for synthesis. Several of the new compounds 7 and 10-14 were synthesized, employing the key synthetic intermediate 23. In a second approach, the natural product (+)-artemisinic acid was utilized as an acceptor for conjugate addition, and the resultant homologated acids were subjected to singlet oxygenation and acid treatment to provide artemisinin analogues. Under a new approach, we developed A one step reaction for the interconversion of artemisinin 1 into artemisitene 22 that did not employ selenium-based reagents and found that 2-arylethyliodides would undergo facile radical-induced conjugate addition to the exomethylene lactone of 22 in good yield. The lactone carbonyls, were removed sequentially by diisobutylaluminum hydride reduction followed directly by a second reduction (BF3-etherate/Et3SiH) to afford the desired corresponding pyrans. Six additional halogen-substituted aromatic side chains were installed via 22 furnishing the bioassay candidates 15-20. The analogues were examined for in vitro antimalarial activity in the W-2 and D-6 clones of Plasmodium falciparum and were additionally tested. in vivo in Plasmodium berghei- and/or Plasmodium yoelii-infected mice. Several of the compounds emerged as highly potent orally active candidates without obvious toxicity, Of these, two were chosen for pharmacokinetic evaluation, 14 and 17.
Structure−Activity Relationships of the Antimalarial Agent Artemisinin. 5. Analogs of 10-Deoxoartemisinin Substituted at C-3 and C-9
作者:Mitchell A. Avery、Sanjiv Mehrotra、Theresa L. Johnson、Jason D. Bonk、Jeffrey A. Vroman、Robert Miller
DOI:10.1021/jm9603577
日期:1996.1.1
the presence of triethylsilane. In this manner, 10-deoxoartemisinin (3) could be obtained from artemisinin (1) in greater than 95% overall yield. All analogs were tested in vitro against W-2 and D-6 strains of Plasmodium falciparum. Several of the analogs were much more active than the natural product (+)-artemisinin (1) or 10-deoxoartemisinin (3). Conventional structure-activity relationships are discussed