Structural Studies on Bioactive Compounds. 28. Selective Activity of Triazenyl-Substituted Pyrimethamine Derivatives against <i>Pneumocystis </i><i>carinii </i>Dihydrofolate Reductase
作者:Malcolm F. G. Stevens、Keith S. Phillip、Daniel L. Rathbone、Dennis M. O'Shea、Sherry F. Queener、Carl H. Schwalbe、Peter A. Lambert
DOI:10.1021/jm970050n
日期:1997.6.1
Triazenyl-substituted pyrimethamine derivatives 10a-s have been prepared by coupling diazotized 2,4-diamino-5-(3-amino-4-chlorophenyl)6-ethyl pyrimidine (1c) with a series of secondary amines in aqueous sodium carbonate solution. The triazenes which are stable and poorly soluble as free bases form more soluble, but unstable, salts with alkanesulfonic acids. The lead dimethyltriazene 2,4-diamino-5-[4-chloro-3-(3,3-dimethyltriazen-1-yl)phenyl]-6- ethylpyrimidine (4a) forms a crystalline ethanesulfonic acid salt (solvated with 2-propanol), which is protonated at the pyrimidine N-1 position as determined by X-ray crystallography. The ability of these new triazenes to inhibit Pneumocystis carinii dihydrofolate reductase in vitro has been compared to that of triazene 4a. The most potent and selective compound, 2,5-diamino-5-[3-[3-[2-(acetyloxy)ethyl]-3-benzyltriazen-1-yl]- 4-chlorophenyl]-6-ethylpyrimidine (14a), has an IC50 value of 0.17 mu M against the microbial enzyme and potentially useful selectivity (rat liver IC50/P. carinii IC50 = 114).
Structural Studies on Bioactive Compounds. 34. Design, Synthesis, and Biological Evaluation of Triazenyl-Substituted Pyrimethamine Inhibitors of <i>Pneumocystis carinii</i> Dihydrofolate Reductase
作者:David C. M. Chan、Charles A. Laughton、Sherry F. Queener、Malcolm F. G. Stevens
DOI:10.1021/jm0108698
日期:2001.8.1
The triazenyl-pyrimethamine derivative 3a (TAB), a potent and selective inhibitor of Pneumocystis carinii DHFR, was selected as the starting point for a lead optimization study. Molecular modeling studies, corroborated by a recent crystal structure determination of the ternary complex of P. carinii DHFR--NADPH bound to TAB, predicted that modifications to the acetoxy residue of the lead inhibitor could