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Two series of chalcone/aryl carboximidamide hybrids 4a–f and 6a–f were synthesised and evaluated for their inhibitory activity against iNOS and PGE2. The most potent derivatives were further checked for their in vivo anti-inflammatory activity utilising carrageenan-induced rat paw oedema model. Compounds 4c, 4d, 6c and 6d were proved to be the most effective inhibitors of PGE2, LPS-induced NO production, iNOS activity. Moreover, 4c, 4d, 6c and 6d showed significant oedema inhibition ranging from 62.21% to 78.51%, compared to indomethacin (56.27 ± 2.14%) and celecoxib (12.32%). Additionally, 4c, 6a and 6e displayed good COX2 inhibitory activity while 4c, 6a and 6c exhibited the highest 5LOX inhibitory activity. Compounds 4c, 4d, 6c and 6d fit nicely into the pocket of iNOS protein (PDB ID: 1r35) via the important amino acid residues. Prediction of physicochemical parameters exhibited that 4c, 4d, 6c and 6d had acceptable physicochemical parameters and drug-likeness. The results indicated that chalcone/aryl carboximidamides 4c, 4d, 6c and 6d, in particular 4d and 6d, could be used as promising lead candidates as potent anti-inflammatory agents. [ABSTRACT FROM AUTHOR]

A series of 3-acetyl-2-aryl-5-methylthio-2,3-dihydro-1,3,4-thiadiazoles 3a–g,N- (4-acetyl-5-aryl-4,5-dihydro-1,3,4-thiadiazol-2-yl) acetamide derivatives 5a–e and spiro-compound 7 was prepared from starting material dithiocarbazates using N-methylpyrrolidone (NMP) /acetic anhydride mixture. Furthermore, a new series of 5-amino-3- (methylthio) -1-substituted-1H-pyrazole-4-carbonitrile derivatives 12a–d was prepared using two synthetic routes: (i) via reaction of bis (methylthio) methylene malononitrile 8 with carbothiohydrazides 11a–d, or (ii) via reaction of methyl 5-amino-4-cyano-3- (methylthio) -1H-pyrazole-1-carbodithioate 9a with primary/secondary amines. The antimicrobial screening of newly synthesized compounds revealed that compounds 3b, 7, and 12d are the most potent against the Gram-positive (S. aureus) and the Gram-negative (E. coli) bacteria compared to ciprofloxacin as reference drug. Mechanistically, the theoretical docking results of 3b, 7 and 12d suggested that they may act as potent inhibitors of theDNA gyrase. [ABSTRACT FROM AUTHOR]

Ethyl 4-substituted-3-oxo-quinoxaline-2-carboxylates 3–5 were obtained via alkylation of ethyl 3-oxo-3,4-dihydroquinoxaline-2-carboxylate (1). Compound 1 was heterocyclized using hydrazines, ethylenediamine, and ethanolamine to give pyrazoloquinoxalines 6, 7, diazepinoquinoxaline 8, and oxazepinoquinoxaline 10. The quinoxaline-2-carboxamides 9, 11, 12 were prepared via condensation of compound 1 with different amines. Compound 1 was thiated using Lawesson's reagent affording quinoxaline-3-thione 13, in fair yield. In addition, the reaction of 4-methyl-3-oxoquinoxaline 3 with some binucleophiles led to a series of new oxoquinoxaline derivatives 14–18. The molecular structure of compounds 1, 3, and 9 was confirmed by X-ray crystallography. The anti-proliferative activity showed that among all the tested compounds, compounds 3, (IC50 2.51 ± 3.0, 4.22 ± 1.6 and 2.27 ± 1.9 µM), 11 (IC50 1.32 ± 2.61, 1.41 ± 1.23 and 1.18 ± 1.91 µM) and 17 (IC50 1.72 ± 1.32, 1.85 ± 0.94 and 1.92 ± 4.83 µM) showed noteworthy anti-proliferative effects against the three cancer cell lines, HCT116, HePG2 and MCF7, respectively, compared to the reference drugs doxorubicin (IC50 1.41 ± 0.58, 0.90 ± 0.62 and 1.01 ± 3.02 µM) and erlotinib (IC50 1.63 ± 0.81, 1.57 ± 0.62 and 1.49 ± 0.54 µM). Compounds 3 (0.899 nM), 11 (0.508 nM) and 17 (0.807) showed strong EGFR inhibitory activity compared to Erlotinib (0.439 nM) and these results are in agreement with the docking study. These results suggest that compounds could probably be promising anticancer agents with EGFR inhibitory activity. [ABSTRACT FROM AUTHOR]

This work focuses on optimizing an efficient green synthesis of arylamidoximes from appropriate nitrile and hydroxylamine hydrochloride in water and triethylamine (1.6 mol equivalent) as a base at room temperature for 6 h. This new green synthetic methodology is compared with previously known methods. The main advantages of this new process reported are good yield, easier work-up and short reaction times. Moreover, some of the synthesized arylamidoximes converted to 1,2,4-oxadiazole derivatives 13a,b and 14via the reaction with (4-acetylphenoxy)acetic acid 12. [ABSTRACT FROM AUTHOR]