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PurposeThis work aims to synthesize a series of novel acyclic and/or heterocyclic systems, as precursors for dyes with potential antimicrobial activity that could be used for simultaneous dyeing and antimicrobial textile finishing. Thus, a series of novel pyridine, thiophene and pyrazolo[3,4-b]pyridine derivatives were synthesized, and their antimicrobial and textile finishing properties were studied and evaluated.Design/methodology/approachThe synthesis, structure elucidation and antimicrobial activities of the newly synthesized compounds based on 4,4-dicyano-3-phenyl-but-3-enoic acid phenylamide (1) were demonstrated. The minimal inhibitory concentration in μg/mL of the compounds showed significant antimicrobial activity against most of the tested organisms. On the other hand, their spectral characteristics and fastness properties were measured and evaluated. Antimicrobial activities of the dyed fabrics in terms of inhibition zones (mm) were measured and evaluated.FindingsA series of novel heterocyclic compounds (Schemes 1-3) were synthesized based on starting material (1). Compounds (1), 2, 4a, 8a and 9c exhibited comparable or even higher antibacterial activities than the selected standards (ampicillin), while compounds 2, 3c, 3d, 4a and 8b revealed higher antifungal activities than the selected standard (cycloheximide). On the other hand, some dyes showed high antimicrobial evaluation on the dyed fabrics (nylon 66, acetate and polyester) expressed as size (mm) of inhibition zones (Tables I-IV).Practical implicationsResults revealed that many hydrazo and azo derivatives were synthesized from some pyridines and thiophenes. The antimicrobial evaluation and textile finishing of the newly synthesized products revealed significant and potent values of antimicrobial activity.Originality/valueAll the synthesized compounds were novel and most of them exhibited higher antimicrobial activities than the selected standards antibiotics, thus are valuable for simultaneous dyeing and antimicrobial functional finishing of textile fabrics.

Many studies mentioned that Melatonin considers an anti-cancer agent. So in this study, a lot of novel Melatonin derivatives incorporated different heterocyclic ring systems such as triazole, thiadiazole, tetrazole, thiazole, thiophene and pyrazole were synthesized. The synthesized compounds 5, 6, 8, 11, 15, 16 and 19 were evaluated as anti-cancer by using two human cancer cell lines, Breast cancer (MCF7) and colon cancer (HCT-116). The synthesized compounds showed a gradual decrease in the cell viability of the two cell lines. We also observed that compound 16 was the lowest IC50 and the highest cytotoxic effects against the two cancer cell lines. Furthermore, the molecular-docking study was employed to determine the possible mode of action of the synthesized compounds against proteins (CDK2 and P53-MDM2) which, were considered to be potential proteins involved in the pathogenesis of cancer. We observed that compound 16 was the best-docked ligand against the targeted proteins, as it displayed the lowest binding energies, critical hydrogen bonds, and hydrophobic interactions compared to other tested compounds.

Reactivity of 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3- carbonitrile towards thioglycolic acid resulted in thiazole derivative 1. The latter reacted with different chemical reagents to give thiazole, pyrano[2,3-d]thiazole and thiazolo[ 4,5-d]thiazole derivatives. Cytotoxicity effects of the newly synthesized products against six cancer cell lines, namely, human gastric cancer (NUGC), human colon cancer (DLD- 1), human liver cancer (HA22T and HEPG-2), human breast cancer (MCF) and nasopharyngeal carcinoma (HONE-1) as well as against a normal fibroblast cell (WI-38) were evaluated. The study showed that the 4,5,6,7 tetrahydrobenzo[ b] thiophene derivatives 6a, 7, 8a,b, 9b and 10b,c w ere t he most active compounds. Their potencies were attributed to the presence of the electron withdrawing groups.

The 2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene was the key starting compound used to synthesize new thiazole, pyrimidine, pyran, pyridine and thiazine derivatives. The cytotoxicity of the synthesized compounds was studied towards the three cancer cell lines namely MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (central nervous system (CNS) cancer) in addition to the normal cell line (WI-38) using doxorubicin as the reference drug. The study showed that compounds 5, 9a, 15b, 17c, 18 and 21b were the most potent compounds.

The reaction of ethyl cyanoacetate 2 with o -phenylenediamine 1 gave the 2-cyanomethylbenzo[ c ]imidazole 3. The latter compound was used as the key starting material to synthesis biologically active heterocyclic derivatives. Thus, the reaction of compound 3 with cyclohexanone 4 and either of benzaldehyde ( 5a ), 4-methoxybenzaldehyde ( 5b ) or 4-chlorobenzaldehyde ( 5c ) gave the annulated derivatives 6a-c , respectively. The antitumor evaluations of the newly synthesized products against the three cancer cell lines MCF-7 (breastadeno-carcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer) showed that compounds 6b , 12 , 22b , 22c , 25 , 32 , 33 and 35 exhibited optimal cytotoxic effect against cancer cell lines, with IC 50 ’s in the nM range. Bioactive compounds are often toxic to shrimp larvae. Thus, in order to monitor these chemicals’ in vivo lethality to shrimp larvae ( Artemiasalina ), Brine-Shrimp Lethality Assay was used. Compounds 22b, 25 and 33 showed non toxicity against the tested organisms.

Attempting to produce cyclized systems with potential anti-proliferative activity, a series of novel thiophene and benzothiophene derivatives were designed and synthesized. The reactivity of the latter derivatives towards different chemical reagents was studied. Twenty-one compounds were synthesized and evaluated as anti-cancer agents. The results showed that ethyl 5-amino-3-(4-chlorostyryl)-4-cyanothiophene-2-carboxylate (5b), ethyl 5-amino-4-((4-methoxyphenyl)carbonyl)-3-methylhiophene-2-carboxylate (8c) and 5-3-(ethoxy-3-oxopropanamido)-3-methyl-4-(phenylcarbamoyl)thiophene-2-carboxylate (9) were the most active compounds towards three tumor cell lines – MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer) and a normal fibro-blast human cell line (WI-38) compared to the anti-proliferative effects of the reference control doxorubicin.