Bi-heterocyclic benzamides as alkaline phosphatase inhibitors: Mechanistic comprehensions through kinetics and computational approaches.

Novel bi-heterocyclic benzamides were synthesized by sequentially converting 4-(1H-indol-3-yl)butanoic acid (1) into ethyl 4-(1H-indol-3-yl)butanoate (2), 4-(1H-indol-3-yl)butanohydrazide (3), and a nucleophilic 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazole-2-thiol (4). In a parallel series of reactions, various electrophiles were synthesized by reacting substituted anilines (5a-k) with 4-(chloromethyl)benzoylchloride (6) to afford 4-(chloromethyl)-N-(substituted-phenyl)benzamides (7a-k). Finally, the nucleophilic substitution reaction of 4 was carried out with newly synthesized electrophiles, 7a-k, to acquire the targeted bi-heterocyclic benzamides, 8a-k. The structural confirmation of all the synthesized compounds was done by IR, 1 H NMR, 13 C NMR, EI-MS, and CHN analysis data. The inhibitory effects of these bi-heterocyclic benzamides (8a-k) were evaluated against alkaline phosphatase, and all these molecules were identified as potent inhibitors relative to the standard used. The kinetics mechanism was ascribed by evaluating the Lineweaver-Burk plots, which revealed that compound 8b inhibited alkaline phosphatase non-competitively to form an enzyme-inhibitor complex. The inhibition constant Ki calculated from Dixon plots for this compound was 1.15 µM. The computational study was in full agreement with the experimental records and these ligands exhibited good binding energy values. These molecules also exhibited mild cytotoxicity toward red blood cell membranes when analyzed through hemolysis. So, these molecules might be deliberated as nontoxic medicinal scaffolds to render normal calcification of bones and teeth.

Synthesis, Antibacterial and Lipoxygenase Inhibition Studies of N-(Alkyl/aralkyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamides.

OBJECTIVES: The present research work was aimed to synthesize some new sulfonamides bearing 1,4-benzodioxin ring, which might have suitable antibacterial potential and can be used as possible therapeutic agents for inflammatory ailments. MATERIALS AND METHODS: The synthesis was accomplished by the reaction of 2,3-dihydro-1,4-benzodioxin-6-amine (1) with 4-methylbenzenesulfonyl chloride (2) using 10% aqueous Na2CO3 to afford N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamide (3). Further the parent molecule 3 was reacted with different alkyl/aralkyl halides (4a-e) to achieve N-(alkyl/aralkyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamides (5a-e), using polar aprotic solvent; N,N-dimethylformamide (DMF) and catalytic amount of lithium hydride as base. The characterization of synthesized compounds was conducted by contemporary spectral techniques e.g., IR, 1H-NMR and EI-MS. Then these molecules were subjected to screening against various bacterial strains and their inhibitory potential against Lipoxygenase was also ascertained. RESULTS: The screening results against various Gram-positive and Gram-negative bacterial strains revealed that N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamide (3), N-(2-bromoethyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamide (5a) and N-(2-phenethyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamide (5b) showed good inhibitory activity as compared to standard Ciprofloxacin. Moreover, N-(3-phenylpropyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfonamide (5c) and N-(4-chlorobenzyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-methylbenzenesulfon-amide (5e) displayed decent inhibition against lipoxygenase enzyme relative to standard Baicalein. CONCLUSION: On the basis of results obtained it can be concluded that the synthesized sulfonamides may provide an overall indispensable basis to introduce new drug candidates for the cure of inflammatory and other associated diseases.

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.