Synthesis, spectral analysis and pharmacological study of N'- substituted-2-(5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazides

ABSTRACT A series of molecules bearing multiple functional groups were synthesized to study their antibiotic effect against Gram-positive and Gram-negative bacteria and lipoxygenase activity as well. 2,4-Dimethylcarbolic acid (1) was refluxed with ethyl 2-bromoacetate to synthesize ethyl 2-(2,4-dimethylphenoxy)acetate (2). Compound 2 was converted to the corresponding hydrazide 3, again on refluxing with hydrazine. The compound 5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-thiol (4) was synthesized by the reaction of 3 and CS2 in the presence of KOH. Compound 4 was further converted to the corresponding ester 5 and then 2-(5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide (6). The final molecules N'-substituted-2-(5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide, 8a-m, bearing ether, 1,3,4-oxadiazole, thioether, hydrazone and azomethine functional groups were synthesized by stirring the aryl carboxaldehydes 7a-m with 6 in methanol at room temperature. The depicted structures of all synthesized molecules were corroborated by IR, 1H-NMR and EIMS spectral data analysis. 8m and 8i showed substantial antibacterial activity and lipoxygenase inhibitory activity, respectively

Synthesis of some novel enzyme inhibitors and antibacterial agents derived from 5-(1-(4-tosyl)piperidin-4-yl)-1,3,4-oxadiazol-2-thiol

ABSTRACT Keeping in mind the pharmacological importance of the 1,3,4-oxadiazole moiety, a series of new S-substituted derivatives, 5a-h, of 5-(1-(4-tosyl)piperidin-4-yl)-1,3,4-oxadiazol-2-thiol (3) were synthesized. The reaction of p-toluenesulfonyl chloride (a) and ethyl isonipecotate (b) produced ethyl 1-(4-tosyl)piperidin-4-carboxylate (1) which was further transformed into 1-(4-tosyl)piperidin-4-carbohydrazide (2) by hydrazine hydrate in methanol. Compound 2 was refluxed with CS2 in the presence of KOH to synthesize 5-(1-(4-tosyl)piperidin-4-yl)-1,3,4-oxadiazol-2-thiol (3). The desired compounds, 5a-h, were synthesized by stirring 3 with aralkyl halides, 4a-h, in DMF using NaH as an activator. The structures of synthesized compounds were elucidated by 1H-NMR, IR and EI-MS spectral studies. These compounds were further evaluated for enzyme inhibitory activity against lipoxygenase and alpha-glucosidase, along with antibacterial activity against Gram-negative and Gram-positive bacteria

Convergent synthesis of new N -substituted 2-{[5-(1H -indol-3-ylmethyl)-1,3,4-oxadiazol-2-yl]sulfanyl}acetamides as suitable therapeutic agents

abstract A series of N-substituted 2-{[5-(1H-indol-3-ylmethyl)-1,3,4-oxadiazol-2-yl]sulfanyl}acetamides (8a-w) was synthesized in three steps. The first step involved the sequential conversion of 2-(1H-indol-3-yl)acetic acid (1) to ester (2) followed by hydrazide (3) formation and finally cyclization in the presence of CS2 and alcoholic KOH yielded 5-(1H-indole-3-yl-methyl)-1,3,4-oxadiazole-2-thiol (4). In the second step, aryl/aralkyl amines (5a-w) were reacted with 2-bromoacetyl bromide (6) in basic medium to yield 2-bromo-N-substituted acetamides (7a-w). In the third step, these electrophiles (7a-w) were reacted with 4 to afford the target compounds (8a-w). Structural elucidation of all the synthesized derivatives was done by 1H-NMR, IR and EI-MS spectral techniques. Moreover, they were screened for antibacterial and hemolytic activity. Enzyme inhibition activity was well supported by molecular docking results, for example, compound 8q exhibited better inhibitory potential against α-glucosidase, while 8g and 8b exhibited comparatively better inhibition against butyrylcholinesterase and lipoxygenase, respectively. Similarly, compounds 8b and 8c showed very good antibacterial activity against Salmonella typhi, which was very close to that of ciprofloxacin, a standard antibiotic used in this study. 8c and 8l also showed very good antibacterial activity against Staphylococcus aureus as well. Almost all compounds showed very slight hemolytic activity, where 8p exhibited the least. Therefore, the molecules synthesized may have utility as suitable therapeutic agents

Potent, Orally Bioavailable, and Efficacious Macrocyclic Inhibitors of Factor XIa. Discovery of Pyridine-Based Macrocycles Possessing Phenylazole Carboxamide P1 Groups

Factor XIa (FXIa) inhibitors are promising novel anticoagulants, which show excellent efficacy in preclinical thrombosis models with minimal effects on hemostasis. The discovery of potent and selective FXIa inhibitors which are also orally bioavailable has been a challenge. Here, we describe optimization of the imidazole-based macrocyclic series and our initial progress toward meeting this challenge. A two-pronged strategy, which focused on replacement of the imidazole scaffold and the design of new P1 groups, led to the discovery of potent, orally bioavailable pyridine-based macrocyclic FXIa inhibitors. Moreover, pyridine-based macrocycle 19, possessing the phenylimidazole carboxamide P1, exhibited excellent selectivity against relevant blood coagulation enzymes and displayed antithrombotic efficacy in a rabbit thrombosis model