71006-02-5Relevant articles and documents
Synthesis and further transformations of 8-chloro-3,4-dihydroisoquinoline
Hargitai, Csilla,Nagy, Tamás,Halász, Judit,Koványi-Lax, Gy?rgyi,Németh, Gábor,Simig, Gyula,Volk, Balázs
, p. 7009 - 7017 (2018/10/24)
Two procedures for the synthesis of barely accessible 8-chloro-3,4-dihydroisoquinoline were investigated. The first approach is based on a directed ortho-lithiation of N-pivaloyl meta-chlorophenylethylamine, followed by formylation and subsequent ring closure under acidic conditions. In the second, more advantageous variant, the N-hydroxyethyl ortho-chlorobenzylamine intermediate undergoes a Friedel-Crafts reaction, and the resulting tetrahydro derivative is oxidized with N-bromosuccinimide. The 8-chloro-3,4-dihydroisoquinoline key intermediate is then applied in Suzuki reactions to give various 8-aryl-3,4-dihydroisoquinolines, which are finally treated with alkyl or aryllithiums to give 1-substituted 8-aryl-1,2,3,4-tetrahydroisoquinolines. These novel 1,2,3,4-tetrahydroisoquinoline derivatives can be used as building blocks in the synthesis of potential drug candidates.
Structural studies on bioactive compounds. 34.1 Design, synthesis, and biological evaluation of triazenyl-substituted pyrimethamine inhibitors of Pneumocystis carinii dihydrofolate reductase
Chan,Laughton,Queener,Stevens
, p. 2555 - 2564 (2007/10/03)
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 exploit binding opportunities in the vicinity of an active site pocket bounded by residues Ile33, Lys37, and Leu72. Substitutions in the benzyl moiety with electron-donating and electron-withdrawing groups were predicted to probe face-edge interactions with amino acid Phe69 unique to the P. carinii enzyme. New triazenes 10a-v and 12a-f were prepared by coupling the diazonium tetrafluoroborate salt 6b of aminopyrimethamine with substituted benzylamines or phenethylamines. The most potent of the new inhibitors against P. carinii DHFR was the naphthylmethyl-substituted triazene 10t (IC50: 0.053 μM), but a more substantial increase in potency against the rat liver DHFR led to a reduction in selectivity (ratio rat liver DHFR IC50/P. carinii DHFR IC50: 5.36) compared to the original lead structure 3a (ratio rat liver DHFR IC50/P. carinii DHFR IC50: 114).
