The rate of microbial resistance has continued to rise significantly as the availability of new antibiotics has declined. A new series of pyridine and thienopyridine derivatives were designed, synthesized and tested as antimicrobial agents. The reaction of 4-bromo acetophenone and vetraldehyde (3,4-dimethoxy benzaldehyde) in ethanol and sodium hydroxide solution afforded the corresponding chalcone which was used as a suitable precursor to prepare a new series of pyridine derivatives. The treatment of the latter chalcone with 2-cyanothioacetamide afforded the corresponding pyridinethione which was used as a precursor to synthesize the targeted thienopyridine derivatives in good to excellent yield by the reaction with 2-chloro-N-arylacetamide derivatives, α-haloketones, methyl iodide or chloroacetonitrile in one or two steps. The structure of the synthesized compounds was confirmed chemically by their preparations with other pathways and their spectral data. The newly synthesized pyridine and thienopyridine derivatives exhibited good to strong antimicrobial activity against microbial strains E. coli, B. mycoides and C. albicans. With maximal antimicrobial activity against B. mycoides (33 mm) and C. albicans (29 mm), respectively, compounds 12a and 15 demonstrated the highest inhibition zone. Compound 12a prevented the growth of E. coli, at MIC level of 0.0195 mg/mL, and B. mycoides and C. albicans at MIC level below than 0.0048 mg/mL, respectively. Additionally, compound 15 prevented the visible growth of E. coli, B. mycoides, and C. albicans at MIC values of >0.0048, 0.0098, and 0.039 mg/mL, respectively. The relation between the chemical structure of the synthesized pyridine and thienopyridine compounds and their antimicrobial properties was discussed in the SAR study.

Twelve novel chalcone derivatives were prepared using the Claisen–Schmidt condensation reaction. The reaction of 4‐acetyl‐5‐furan/thiophene‐pyrazole derivatives 5 with the corresponding aldehydes 6 afforded the targeted chalcone derivatives 7a–l in good yields. The newly synthesized chalcones were fully characterized by spectrometric and elemental analyses. The in vitro anticancer activities of the novel compounds 7a–l were evaluated against four human cancer cell lines: HepG2 (human hepatocellular carcinoma), MCF7 (human Caucasian breast adenocarcinoma), A549 (lung carcinoma), and BJ1 (normal skin fibroblasts). Compound 7g emerged as the most promising compound, with IC₅₀ = 27.7 µg/ml against A549 cells compared to the reference drug doxorubicin (IC₅₀ = 28.3 µg/ml), and IC₅₀ = 26.6 µg/ml against HepG2 cells compared to the reference drug doxorubicin (IC₅₀ = 21.6 µg/ml). The gene expression and DNA damage values and the DNA fragmentation percentages for compound 7g were determined on the lung and liver cell lines. The expression levels of the AMY2A and FOXG1 genes increased significantly (p < 0.01) in the negative samples of lung cancer cells compared with treated cells. Also, the expression values of the PKM and PSPH genes improved significantly (p < 0.01) in the negative samples compared with treated samples of liver cancer cells. The DNA damage values increased significantly (p < 0.01) in treated lung cell line samples (7g) and the positive control. The results showed a significant decrease (p < 0.05) in DNA damage values in the negative samples of liver cancer cells compared to those treated with 7g. However, the DNA fragmentation values increased significantly (p < 0.01) in the treated lung and liver cell line samples compared with the negative control.