New tetrahydropyrimidine-1,2,3-triazole clubbed compounds: Antitubercular activity and Thymidine Monophosphate Kinase (TMPKmt) inhibition

Two series of new tetrahydropyrimidine (THPM)-1,2,3-triazole clubbed compounds were designed, synthesized and screened for their antitubercular (anti-TB) activity against M. tuberculosis H₃₇Rv strain using microplate alamar blue assay (MABA). The most active compounds 5c, 5d, 5e and 5f were further examined for their cytotoxicity against the growth of RAW 264.7 mouse macrophage cells using MTT assay. The four compounds showed safety profiles better than or comparable to that of ethambutol (EMB). These compounds were evaluated for their inhibition activity against mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt). Compounds 5c and 5e were the most potent exhibiting comparable inhibition activity to that of the natural substrate deoxythymidine monophosphate (dTMP). An in silico study was performed including docking of the most active compounds 5c and 5e into the TMPKmt (PDB: ID 1G3U) binding pocket in addition to prediction of their physicochemical and pharmacokinetic properties to explore the overall activity of these anti-TB candidates. Compounds 5c and 5e are promising anti-TB agents and TMPKmt inhibitors with acceptable oral bioavailability, physicochemical and pharmacokinetic properties.

Design, synthesis and evaluation of some pyrazolo[3,4-d]pyrimidines as anti-inflammatory agents

New pyrazolo[3,4-d]pyrimidines substituted with various functionalities or attached to a substituted pyrazole ring through different linkages were synthesized. The synthesized compounds were evaluated for their anti-inflammatory activity using in vitro COX-1/COX-2 inhibition assay and in vivo formalin induced paw edema and cotton pellet-induced granuloma assays. Results revealed that compounds 17b and 18 possessed COX-1/COX-2 selectivity indices higher than diclofenac sodium and celecoxib. However, compounds 16a,b exhibited selectivity indices higher than diclofenac sodium and nearly equivalent to celecoxib, whereas, 9b displayed selectivity index comparable to diclofenac sodium. In vivo anti-inflammatory data showed that compounds 9b, 16a, 18 displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, the pyrazolyl derivatives 9b, 16b and 17b displayed anti-inflammatory activity about 2-2.5-fold that of diclofenac sodium and nearly 8-10.5-fold that of celecoxib in the cotton pellet-induced granuloma assay. The ulcerogenic effect of the active compounds was also investigated and results revealed that compounds 16a, 17a,b and 18 showed good gastrointestinal safety profile. Based on this, compounds 16a and 18 were considered as safe and effective leads in managing acute inflammation, while, 17b was prominent in controlling chronic inflammation.

Design, synthesis and molecular modeling studies of new series of antitumor 1,2,4-triazines with potential c-Met kinase inhibitory activity

The receptor tyrosine kinase c-Met is an attractive target for therapeutic treatment of cancers nowadays. Herein we describe the design and synthesis of a novel series of 1,2,4-triazine derivatives based on our lead NCI 748494/1, possessing different N-linkers to aromatic and heterocyclic rings. In addition, a molecular hybrid series combining the 1,2,4-triazine scaffold to the well-known anticancer drug 6-mercaptopurine (6-MP) was synthesized in order to explore its "double-drug" antitumor effect. The synthesized compounds were evaluated for their in vitro antitumor activity against three c-Met addicted cancer cell lines (A549, HT-29 and MKN-45). Most compounds showed moderate to excellent antitumor activity. Compound 3d showed potent inhibitory activity more than reference Foretinib, BMS-777607 and NCI 748494/1 with IC₅₀ values in the range 0.01-0.31 µM against the cancer cell lines. The calculated IC₅₀ of 3d against c-Met kinase was found to be 2.71 µM, which is more potent than NCI 748494/1 (IC₅₀ = 31.70 µM). Docking studies were performed to identify the binding mode of 3d with c-Met kinase domain in comparison to moderate and weak derivatives. The present study clearly demonstrates that 1,2,4-triazine ring exhibits promising antitumor activity and the double-drug optimization strategy led to identifying 3d as a potent c-Met kinase inhibitor suitable for further development.

Synthesis of 5,6-Diaryl-1,2,4-triazines

The synthesis of 6-(4-methoxyphenyl)-5-phenyl-3-oxo-2,3-dihydro-1,2,4-triazine (5a) from 4-methoxybenzoin, 4-methoxybenzil, or 4-methoxybenzoin semicarbazone and semi-carbazide hydrochloride is reported. The condensation of 4-methoxybenzil with thiosemi-carbazide yielded 6-(4-methoxyphenyl)-5-phenyl-3-thioxo-2,3-dihydro-I,2,4-triazine (5b) which was converted to its 3-oxo analogue 5 a with acetic anhydride. Reduction of 5 a and 5 b with zinc and aqueous acetic acid led to the corresponding 2,3,4,5-tetrahydro-1,2,4-triazines 6 a and 6b, respectively. Oxidation of 5 b with iodine in sodium carbonate solution afforded bis [6-(4-methoxyphenyl)-5-phenyl-1,2,4-triazin-3-yl]disulphide (7). Analogous triazines were prepared by condensing 3,3'-diiodobenzil with semicarbazide hydrochloride or thiosemicarbazide.

Synthesis, estrogen receptor binding affinity and biological evaluation of some 2-substituted estrone derivatives

This report details the preparation of modified estrogens which are structurally designed to possess estrogenic and/or antiestrogenic activity. The prominent feature of these estrogens is the introduction of a novel side chain in the 2-position of ring A of the steroid nucleus. Their synthesis includes the use of transformations based upon Mannich base chemistry: preparation of the intermediate 2-dimethylamino-methylestrone via aminomethylation of estrone and introduction of various functionalities via reaction of this Mannich base with different reagents. When evaluated for their interaction with the estrogen receptor by competitive binding assays, the tested products were found to be relatively weak competitors at 0 degree C. The uterotrophic and post-coital antifertility assays indicated effects varying in magnitude relative to estradiol. Ethyl[(2'-acetyl-3'-(3-hydroxyestra-17-oxo-1,3,5 (10)-trien-2-yl)]propionate (15) showed uterotrophic and antiimplantation activities of 95% and 20% respectively.

4',17-dioxo-5'H-estra-1(10),4-dieno[3,2-b]furan: synthesis, binding affinity to the estrogen receptor, uterotrophic and antiimplantation activities

4',17-Dioxo-5'H-estra-1(10),4-dieno[3,2-b]furan (3) has been prepared by several routes starting from 2-bromoacetylestrone (2). Performance of the reaction with thiourea at elevated temperature provided compound 3 in good yield. When other reagents such as thiosemicarbazide, morpholine, sodium hydroxide or sodium hydride were treated with 2-bromoacetylestrone at room temperature, the furano derivative 3 was also obtained as the sole product. This new type of structural modification provided an estrogen nucleus deprived of the 3-hydroxyl function which was previously thought to be an essential requisite for binding to the estrogen receptor (ER). When evaluated in vitro for binding to the ER and in vivo for uterotrophic and antifertility activities, the furano derivative 3 was capable of inhibiting [3H]E2 binding by 16% while still eliciting high uterotrophic (99%) and postcoital antiimplantation (100%) activities relative to estradiol.

Syntheses and in vitro antimicrobial evaluation of some benzimidazol-2-ylmethylthioureas, benzimidazol-2-ylacetylthiosemicarbazides and products of their condensation with monochloroacetic acid

N-Benzimidazol-2-ylacetyl-N'-[alkyl- and arylthio (carbamoyl)]hydrazines and N-benzimidazol-2-ylmethyl-N'-alkyl- and -arylthioureas were subjected to condensation with monochloroacetic acid to afford N-benzimidazol-2-ylacetyl-N'-2,3, 4,5-tetrahydro-4-oxo-3-alkyl- and -arylthiazol-2-ylidenehydrazines and 3-benzimidazol-2-ylmethyl-2-alkyl- and arylimino-2,3-dihydrothiazol-4-(5H)ones, respectively. In preliminary antimicrobial testing, some compounds turned out to have significant activity against Staphylococcus aureus.

Syntheses and in vitro antimicrobial activities of thiazolo-[3,2-a]benzimidazol-3(2H)-ones

Taking advantage of the nucleophilic reactivity of the 2-methylene carbon atom in thiazolo[3,2-a]-benzimidazol-3(2H)-one, a number of 2-isatinylidene and 2-arylazo derivatives have been prepared. The novel compounds were subjected to antimicrobial testing.

Arylidenepyruvic acid thiosemicarbazone and thiazoline derivatives as potential antimicrobial agents

Two novel series of arylidenepyruvic acid thiosemicarbazone and thiazoline derivatives were synthesized and evaluated as potential antimicrobial agents. These substances did not exhibit any significant antibacterial effects when tested against a variety of microorganisms.

Hydroxy- and amino-substituted piperidinecarboxylic acids as gamma-aminobutyric acid agonists and uptake inhibitors

The syntheses of (3RS,4RS)-4-hydroxypiperidine-3-carboxylic acid (4), (3RS,5SR)-5-hydroxypiperidine-3-carboxylic acid (20), (3RS,4SR)-4-acetamidopiperidine-3-carboxylic acid (10), and (3RS,5SR)-5-acetamidopiperidine-3-carboxylic acid (18), related to the specific gamma-aminobutyric acid (GABA) uptake inhibitors (RS)-piperidine-3-carboxylic acid (nipecotic acid) and (3RS,4SR)-4-hydroxypiperidine-3-carboxylic acid (21), are described. Furthermore, (3RS,4SR)-3-hydroxypiperidine-4-carboxylic acid (14), related to the specific GABA agonist piperidine-4-carboxylic acid (isonipecotic acid), has been synthesized. The structures of 4, 10, 14, 18, and 20 have been established by 270-MHz 1H NMR spectroscopic analyses. The affinity of the compounds for the GABA receptors and for the neuronal (synaptosomal) GABA uptake system in vitro has been measured. Compound 14 interacts selectively with the GABA receptors but less effectively than isonipecotic acid and the cis-isomer 22. Compounds 4, 18, and 20 are inhibitors of the GABA uptake system, although much weaker than nipecotic acid and (3RS,4SR)-4-hydroxypiperidine-3-carboxylic acid (21). Compound 10 is inactive in both test systems.

Potential antineoplastics I: substituted 3,5-dioxo-and 3-thioxo-5-oxo-2,3,4,5-tetrahydro-1,2,4-triazines

The synthesis of some 6-substituted 3,5-dioxo- and 3-thioxo-5-oxo-2,3,4,5-tetrahydro-1,2,4-triazines for possible antineoplastic activity is reported. The assigned structures were substantiated by IR, NMR, and mass spectral studies of representative members of the series. Four compounds were tested against P-388 lymphocytic leukemia and were inactive.