Design, Synthesis and Antiproliferative Evaluation of Novel 1,2,4-Triazole/Schiff Base Hybrids with EGFR and B-RAF Inhibitory Activities

Background:

1,2,4-triazoles possess a broad spectrum of biological activities such as analgesic, antimicrobial, antitubercular, anti-inflammatory and antineoplastic activities. This heterocycle and their derivatives were included into a wide variety of therapeutically interesting drugs. Hence, it is of great interest to explore new 1,2,4-triazoles as cytotoxic agents targeting EGFR, B-Raf kinases.

Methods:

The final compounds 9a-b, 10a-b, 11a-b, 12a-b, 13a-b and 14a-f were prepared by refluxing a mixture of triazole 3a-b and 7a-d with the corresponding benzaldehyde derivatives 8a-d in absolute ethanol to afford the target final compounds in good yields. The newly synthesized triazole-containing compounds were assessed according to standard protocols for their in vitro antiproliferative activity against four human cancer cell lines including human pancreas cancer cell line (Panc-1), pancreatic carcinoma cells (PaCa-2), colon cancer cells (HT-29) and lung cancer cells (H-460) using the propidium iodide (PI) fluorescence assay. Compounds 9a and 13a were evaluated against EGFR, B-Raf and Tubulin anticancer targets.

Results:

Compounds 9a, 9b, 10a, 11a, 12a, 13a and 13b showed remarkable antiproliferative activity against the tested cell lines with IC50 range of 1.3-5.9µM. Compounds 9a and 13a with the least IC50 values in the anticancer screening assay were tested against three known anticancer targets including EGFR, B-Raf kinase and Tubulin. The results revealed that compound 13a showed the highest potency against B-Raf and EGFR kinases with IC50 = 0.7 and 1.9 µM, respectively.

Conclusion:

1,2,4-triazoles reported herein are potent EGFR, B-Raf inhibitors. These lead compounds will be subjected to more detailed mechanistic studies.

Synthesis, characterization and reactions of 2-deoxo-5-deazaalloxazines

5-Deazaflavins and their homologues have been known as potential riboflavin antagonists, bioreductives, and compounds with potent antitumor activity. 2-Amino-4-methylquinoline-3-carbonitrile (2) was prepared as unreported starting material for several interesting 2-deoxo-5-deazalloxazine derivatives. Cyclization of 2 using formamide afforded the 2,4-deoxo-5-deazaalloxazine derivative 7, which was subjected to deamination with nitrous acid to give the 2-deoxo-5-deazaalloxazine (8). The compound 8 was also obtained via 13 by treating the latter with refluxing formic acid or formamide and used as a precursor for synthesis of several 2-deoxo-5-deazaalloxazines 18, 19, 20, 21 and 22. The pharmacological and biological properties of these compounds are still under investigation.

Synthesis and biological activity of some new benzimidazolyl-azetidin-2-ones and -thiazolidin-4-ones

Arylidene-2-aminobenzimidazoles (1) were prepared by condensation of 2-aminobenzimidazole with aromatic aldehydes. Cyclocondensation of mercaptoacetic acid, chloracetylchloride and phthaloyl glycyl chloride on 1 giving the corresponding 4-thiazolidinones (2) and azetidinones (3 and 4) respectively, in good yields. The biological activities of the prepared compounds were screened against several strains of bacteria.

Synthesis of some new heterocyclic 1,3,4-oxadiazoles with antibacterial activity

2-N-Aryl/heterocyclic carboxamidomethylthio-5-p-chlorophenyl-1,3,4-oxadiazoles have been synthesized by the reaction of 1 and N-aryl/heterocyclic-2-chloracetamides in presence of basic medium. 2 and 3 react with heterocyclic thiols in ethanolic potassium hydroxide to give 3-S-substituted-mercaptomethyl-5-substituted-phenyl-1,3,4-oxadiazol-2-thione 5 and 6 respectively. Tert. amines react with 2 to yield the corresponding amino chlorides in good yield. Some of the prepared compounds were tested as antibacterials against Gram-positive and Gram-negative organism.