SYNTHESIS AND IN VITRO ANTIPROLIFERATIVE ACTIVITY OF NOVEL 2-ARYLIDENEAMINOBENZIMIDAZOLE DERIVATIVES.

A new class of Mannich bases 9-26, derivatives of 2-amino-1H-benzimidazole, were obtained in the condensation of Schiff bases 1-4 or 2-benzylaminobenzimidazoles 5-8 with selected secondary amines: morpholine, piperidine, N-methylpiperazine, N-phenylpiperazine, 1-(2-pyridyl)piperazine, 1(2-methoxyphenyl)piperazine, 1-(2-pyrimidinyl)piperazine and formaldehyde in ethanol. The pyrimido[1,2-albenzimidazole derivatives 27-29 have been synthesized in the reactions of Schiff base 2 with selected compounds containing active methylene group: acetylacetone, benzoylacetone and malononitrile. The structures 1-29 were confirmed by the results of elementary analysis and their IR, 1H- and 13C-NMR spectra. The products 1-29 are of interest for biological studies and can be substrates for further synthesis. All compounds were screened against the cells of MV4-11 human leukemia and then the most active of them 5, 7, 9-16, 24-26, 28, 29 were tested towards human T47D breast and A549 lung cancer cells as well as normal mouse fibroblasts (BALB/3T3). The most active compound against the cancer cell lines was 4-amino-3-cyano-2-(4-hydroxyphenylene)-1,2-dihydropyrimi-do[1,2-a]benzimidazole (29) (IC50 0.23 ± 0.05 µg/mL against MV4-11 cells) showing in parallel very low cytotoxicity towards mouse fibroblasts. Cisplatin was the control drug.

Synthesis and antiproliferative activity in vitro of new 2-thioxoimidazo[4,5-B]pyridine derivatives.

Two series of 2-thioxoimidazo[4,5-b]pyridine derivatives have been synthesized from 2,3-diaminopyridine (1) and 5-halogenosubstituted-2,3-diaminopyridines 2, 3. Mannich bases 7 - 12 and 24 - 29, derivatives of 1-arylamino-6-halogeno-2-thioxoimidazo[4,5-b]pyridine were obtained with selected secondary amines: morpholine, piperidine, 2-methoxyphenylpiperazine, pyrimidyn-2-yl-piperazine and formaldehyde in ethanol. The structures 7 - 12 and 24 - 29 were confirmed by the results of elementary analysis and their IR, 1H-NMR and MS spectra. All given structures 7 - 12 have been optimized to get the most stable low energy conformers. Synthesized compounds were of interest for biological studies or can be substrates for further synthesis. The selected compounds 7 - 10, 12- 17, 22, 25, 27 - 29 were screened for their antiproliferative activity in vitro against human cancer and normal mouse fibroblast cell lines.

Synthesis and antiproliferative activity in vitro of new pyrido[1,4-b]diazepine derivatives and imidazo[4,5-b]pyridine.

A novel series of esters 8-10 and hydrazones 4-6 was synthesized from 4-aryl-2-phenacylidene-1,3,4,5-tetrahydropyrido[2,3-b][1,4]diazepine (1-3). Subsequent treatment of hydrazone 4 with p-chlorbenzaldehyde furnished azine 7. Long-standing heating of ester 8 with hydrazine hydrate afforded 3-[1-(p-chlorophenylene)-2-(5-phenyl-1H-pyrazol-3-yl)-ethyl]-1,3-dihydroimidazo[4,5-b]pyridin-2-one (11). The structures of 4-6 and 8-10 were identified by the results of elemental analysis and their IR, 1H-NMR and MS spectra. Additionally, the structure of 11 was confirmed by X-ray diffraction method. Compounds 8-10 and 11 were examined for their antiproliferative activity in vitro against the cells of 5 human cancer cell lines, using SRB or MTT technique. Among tested compounds, only 11 revealed cytotoxic activity in vitro against all cell lines applied with ID50 (inhibitory dose 50%) values lower than 4 microg/mL, which is an international activity criterion for synthetic compounds. All compounds inhibit the proliferation of HL-60 human promyelocytic leukemia cell line.

Synthesis and antiproliferative activity in vitro of 2-aminobenzimidazole derivatives.

A novel series of Schiff bases 1-11, the derivatives of 2-aminobenzimidazole and substituted aromatic aldehydes, has been synthesised. Compounds 1-11 reduced by NaBH(4) formed 2-benzylaminobenzimidazoles 12-21. 2-(o-Bromobenzylamino)benzimidazole (15) acylated by cinnamoyl chloride gave 2-(o-bromobenzylamino)-1-cinnamoylbenzimidazole (22). Long heating of 15 and 19 with p-nitrocinnamoyl or cinnamoyl chloride led to the formation of pyrimido[1,2-a]benzimidazol-4-ones 23 and 24. The structures of 1-24 were identified by the results of elemental analysis and their IR, (1)H NMR and MS spectra. Among the compounds 1-24 evaluated for their antiproliferative activity in vitro, 16, 19, 20 and 22 exhibited cytotoxic activity against the cells of human cancer cell lines, namely SW707 (rectal), HCV29T (bladder), A549 (lung) and T47D (breast cancer).