Synthesis and antimalarial testing of neocryptolepine analogues: addition of ester function in SAR study of 2,11-disubstituted indolo[2,3-b]quinolines.

This report describes the synthesis, and in vitro and in vivo antimalarial evaluations of certain ester-modified neocryptolepine (5-methyl-5H-indolo[2,3-b]quinoline) derivatives. The modifications were carried out by introducing ester groups at the C2 and/or C9 position on the neocryptolepine core and the terminal amino group of the 3-aminopropylamine substituents at the C11 position with a urea/thiourea unit. The antiplasmodial activities of our derivative agents against two different strains (CQS: NF54, and CQR: K1) and the cytotoxic activity against normal L6 cells were evaluated.

Synthesis and in vitro antimalarial testing of neocryptolepines: SAR study for improved activity by introduction and modifications of side chains at C2 and C11 on indolo[2,3-b]quinolines.

To obtain a high antimalarial activity with neocryptolepine derivatives, modifying and changing the side chains at the C11 position with varying the substituents of an electron-withdrawing or electron-donating nature at the C2 position for a SAR study were executed. Installation of alkylamino and ω-aminoalkylamino groups at the C11 position of the neocryptolepine core was successful. For further variation, the aminoalkylamino substituents were transformed into the corresponding acyclic or cyclic carbamides or thiocarbamides.

Synthesis and in vitro antiproliferative activity of new 11-aminoalkylamino-substituted chromeno[2,3-b]indoles.

To search for new biological activities of the chromeno[2,3-b]indoles, the 5-oxa analog of the indolo[2,3-b]quinolines that are known to have a potent antitumor activity, a series of 11-amino derivatives with various substituents at the C-2 position were prepared. The synthesis of the chromeno[2,3-b]indole structure involves the cyclization of 2-phenoxy-3-indolecarboxylates 3, accessible from the indole-3-carboxylate 1 and phenols 2, producing the chromeno[2,3-b]indol-11(6H)-ones 4, which is followed by dehydroxychlorination with phosphorus oxychloride to afford the 11-chlorochromeno[2,3-b]indoles 5. The treatment of 5 with various amines produced the corresponding 11-aminated chromeno[2,3-b]indoles 6, while some of the 11-ω-aminoalkylamino derivatives 6 were transformed into the 11-ω-sulfonylaminoalkylamino derivatives 8.

Synthesis and in vitro antiproliferative activity of new 11-aminoalkylamino-substituted 5H- and 6H-indolo[2,3-b]quinolines; structure-activity relationships of neocryptolepines and 6-methyl congeners.

The present report describes the synthesis and antiproliferative evaluation of certain 11-aminoalkylamino-substituted 5H- and 6H-indolo[2,3-b]quinolines and their methylated derivatives. These 5-Me- and 6-Me-indolo[2,3-b]quinoline derivatives 10-14, 20 were prepared by amination at the C-11 position of the 11-chloro-5-methyl-5H- and 11-chloro-6-methyl-6H-indolo[2,3-b]quinolines with different substituents on the quinoline ring. The 11-aminoalkylaminomethylated 23, the homologue of 11, was prepared from the same intermediate for a further SAR study.