95458-48-3Relevant academic research and scientific papers
Development of 2,4-diaminopyrimidines as antimalarials based on inhibition of the S108N and C59R+S108N mutants of dihydrofolate reductase from pyrimethamine resistant Plasmodium falciparum
Tarnchompoo, Bongkoch,Sirichaiwat, Chawanee,Phupong, Worrapong,Intaraudom, Chakapong,Sirawaraporn, Worachart,Kamchonwongpaisan, Sumalee,Vanichtanankul, Jarunee,Thebtaranonth, Yodhathai,Yuthavong, Yongyuth
, p. 1244 - 1252 (2007/10/03)
The reduced binding of pyrimethamine to Serl08Asn (S108N) mutants of parasite dihydrofolate reductase (DHFR), which forms the basis of resistance of Plasmodium falciparum to pyrimethamine, is largely due to steric constraint imposed by the bulky side chain of N108 on Cl of the 5-p-Cl-phenyl group. This and other S108 mutants with bulky side chains all showed reduced binding to pyrimethamine and cycloguanil. Less effect on binding to some bulky mutants was observed for trimethoprim, with greater flexibility for the 5-substituent. S108N DHFR also binds poorly with other pyrimethamine derivatives with bulky groups in place of the p-Cl, and the binding was generally progressively poorer for the double (C59R+S108N) mutant. Removal of the p-Cl or replacement with m-Cl led to better binding with the mutant DHFRs. Pyrimethamine analogues with unbranched hydrophobic 6-substituents showed generally good binding with the mutant DHFRs. A number of compounds were identified with high affinities for both wild-type and mutant DHFRs, with very low to no affinity to human DHFR. Some of these compounds show good antimalarial activities against pyrimethamine-resistant P. falciparum containing the mutant DHFRs with low cytotoxicity to three mammalian cell lines.
Stuctural Studies on Bio-active Compounds. Part 5. Synthesis and Properties of 2,4-Diaminopyrimidine Dihydrofolate Reductase Inhibitors bearing Lipophilic Azido Groups
Bliss, Edward A.,Griffin, Roger J.,Stevens, Malcolm F. G.
, p. 2217 - 2228 (2007/10/02)
A series of 2,4-diamino-5-(azidoaryl)-6-alkylpyrimidines has been prepared.The azide (36) (MZP) can be reduced by thiol reagents to the corresponding amine (28) but reductive deazidation occured when the series of azidophenyl derivatives was heated with hydrazine hydrate.Degradation of azide (36) in a trifluoroacetic acid-trifluoromethanesulphonic acid mixture at 0 deg C affords a means of introducing the bulky trifluoromethylsulphonyloxy substituent into the hindered ortho-position of the 5-aryl substituent.The products formed from thermolysis and photolysis of the azide (36) and the planar analogue 2,4-diamino-6-azidoquinazoline (70) derive from the triplet nitrene reactive intermediates. The azido compounds are potent inhibitors of rat liver dihydrofolate reductase although not as active as metoprin.The azide (36), as its ethanesulphonic acid salt, was selected for clinical trial on the basis of its ease of synthesis and suitable biological and pharmaceutical properties, and has a shorter biological half-life than compounds of comparable hydrophobicity.
