Facile synthesis of non-steroidal anti-inflammatory active bisbenzamide-containing compounds

5-(4H)-Oxazolones and Their Benzamides as Potential Bioactive Small Molecules

The five membered heterocyclic oxazole group plays an important role in drug discovery. Oxazolones present a wide range of biological activities. In this article the synthesis of 4-substituted-2-phenyloxazol-5(4H)-ones from the appropriate substituted aldehydes via an Erlenmeyer–Plochl reaction is reported. Subsequently, the corresponding benzamides were produced via a nucleophilic attack of a secondary amine on the oxazolone ring applying microwave irradiation. The compounds are obtained in good yields up to 94% and their structures were confirmed using IR, ¹H-NMR, ¹³C-NMR and LC/MS data. The in vitro anti-lipid peroxidation activity and inhibitory activity against lipoxygenase and trypsin induced proteolysis of the novel derivatives were studied. Inhibition of carrageenin-induced paw edema (CPE) and nociception was also determined for compounds 4a and 4c. Oxazolones 2a and 2c strongly inhibit lipid peroxidation, followed by oxazolones 2b and 2d with an average inhibition of 86.5%. The most potent lipoxygenase inhibitor was the bisbenzamide derivative 4c, with IC₅₀ 41 μM. The benzamides 3c, 4a–4e and 5c were strong inhibitors of proteolysis. The replacement of the thienyl moiety by a phenyl group does not favor the protection. Compound 4c inhibited nociception higher than 4a. The replacement of thienyl groups by phenyl ring led to reduced biological activity. Docking studies of the most potent LOX inhibitor highlight interactions through allosteric mechanism. All the potent derivatives present good oral bioavailability.

Synthesis, anti-inflammatory, analgesic, COX1/2-inhibitory activity, and molecular docking studies of hybrid pyrazole analogues

This article reports on the design, synthesis, and pharmacological activity of a new series of hybrid pyrazole analogues: 5a–5u. Among the series 5a–5u, the compounds 5u and 5s exhibited potent anti-inflammatory activity of 80.63% and 78.09% and inhibition of 80.87% and 76.56% compared with the standard drug ibuprofen, which showed 81.32% and 79.23% inhibition after 3 and 4 hours, respectively. On the basis of in vivo studies, 12 compounds were selected for assessment of their in vitro inhibitory action against COX1/2 and TNFα. The compounds 5u and 5s showed high COX2-inhibitory activity, with half-maximal inhibitory concentrations of 1.79 and 2.51 μM and selectivity index values of 72.73 and 65.75, respectively, comparable to celecoxib (selectivity index =78.06). These selected compounds were also tested for TNFα, cytotoxicity, and ulcerogenicity. Docking studies were also carried out to determine possible interactions of the potent compounds (5u and 5s), which also showed high docking scores of −12.907 and −12.24 compared to celecoxib, with a −9.924 docking score. These selective COX2 inhibitors were docked into the active site of COX2, and showed the same orientation and binding mode to that of celecoxib (selective COX2 inhibitor). Docking studies also showed that the SO₂NH₂ of 5u and 5s is inserted deep inside the selective pocket of the COX2-active site and formed a hydrogen-bond interaction with His90, Arg513, Phe518, Ser353, Gln192, and Ile517, which was further validated by superimposed docked pose with celecoxib.

An efficient and facile synthesis of 3-amino-5-chromenyl-butenolides from 3-formyl chromone, dialkyl acetylenedicarboxylate, and primary amines

A three-component reaction of 3-formyl chromones, dialkyl acetylenedicarboxylate, and isocyanides in the presence of POCl(3) was used as a highly efficient and practical approach for the synthesis of 3-amino-5-chromenyl-butenolides. High yields and high bond forming efficiency, and simple operations are the advantages of this method. Graphical abstract.

Pseudo-five-component reaction between 3-formylchromones, meldrum's acid, isocyanides and primary arylamines: diversity-oriented synthesis of novel chromone-containing peptidomimetics

An efficient and practical method has been developed for the diversity-oriented synthesis of chromone-containing tripeptides via pseudo-five-component reaction between 3-formylchromones, Meldrum's acid, isocyanides and primary aromatic amines for the generation of a wide range of structurally interesting and pharmacologically significant compounds at ambient temperature. It is worth mentioning that in the course of this reaction, five new bonds (two C-C bonds, two C-N bonds and one C═O bond) are formed. In the present reaction three amide bonds are newly formed.

Facile diversity-oriented synthesis of novel dipeptide mimetic compounds containing bioactive molecular skeletons under microwave irradiation

The diversity-oriented synthesis of dipeptide mimetic compounds embedded with bioactive molecular skeletons have been successfully established via microwave-assisted reactions between various 4-arylidene-2-phenyloxazol-5(4H)-ones and a broad scope of amines including aliphatic, aromatic, and heteroaromatic ones. This synthetic approach has prominent features of short reaction time, high yields, operational simplicity, as well as widespread applications, leading to a facile and straightforward access to structurally diverse dipeptide analogues with potential bioactivities. Moreover, the preliminary evaluation on the cytotoxic activity of this type of dipeptide derivatives has resulted in the finding of five compounds with stronger cytotoxicity than doxorubicin hydrochloride at the concentration of 10 μg/mL.

Novel synthesis of [1]-benzothiepino[5,4-b]pyridine-3-carbonitriles and their anti-inflammatory properties

Reaction of 4-arylmethylene-3,4-dihydro-[1]-benzothiepin-5(2H)-ones 1 with malononitrile in the appropriate alcohol in the presence of sodium afforded the 2-alkoxy-4-aryl-5,6-dihydro-[1]-benzothiepino[5,4-b]pyridine-3-carbonitriles 2 and not the isomeric forms [1]-benzothiepino[4,5-c]pyridine-1-carbonitriles 3 in high regioselective manner. The assumed structure of 2 was inferred through independent synthetic reaction of 3,4-dihydro-[1]-benzothiepin-5(2H)-one (4) with ylidenemalononitriles 5 under the same applied reaction conditions and confirmed by single crystal X-ray diffraction studies. However, reaction of 4 with arylidenecyanothioacetamides 6 in refluxing ethanol in the presence of basic catalyst (piperidine or morpholine) does not afford the expected 4-aryl-3-cyano-5,6-dihydro-[1]-benzothiepino[5,4-b]pyridine-2(1H)-thiones 7 and instead 4-aryl-3,5-dicyano-6-thioxo-2(1H)-pyridinethiolate monohydrates were isolated as piperidinium or morpholinium salts 8. On the other hand, reaction of 6 with cyanothioacetamide in the presence of a sufficient amount of basic catalyst yielded exclusively 2-amino-4-aryl-3,5-dicyano-2-pyridinethiolates as piperidinium or morpholinium salts 9. Meanwhile, 7 were prepared through the reaction of 1 with cyanothioacetamide in refluxing ethanol in the presence of a catalytic amount of piperidine. Anti-inflammatory activity screening of the prepared compounds using in vivo acute carrageenan-induced paw oedema in rats exhibited that all the tested compounds possess considerable activity. In addition, few synthesized derivatives reveal remarkable anti-inflammatory properties (2d, k, l) comparable with indomethacin which was used as a reference standard during the pharmacological activity screening studies.