A novel medium size lactam ring analoges as antibacterial agents: Synthesis, biological evaluation and molecular docking studies.

A novel series of medium size (S)-3-alkyl-3,4,6,7-tetrahydro-1H-benzo[e][1,4]diazonine-2,5-dione (6a-f) analogues were synthesized from (E)-3-(2-nitrophenyl)acrylicacid (2) reacting with various amino acid esters using Di-isopropyl Carbodiimide as a coupling agent. The final cyclization is carried out by using reagent 1-Ethyl-3(3-dimethylaminopropyl) Carbodiimide Hydrochloride. The synthesized compounds have been supported by Mass, 1H-NMR and 13C-NMR. Further antibacterial studies were conducted, where some molecules are noticed with potent activity, especially molecule 6d shown highest activity which was also supported by molecular docking studies. All final molecules were docked with enzyme peptide deformylase to determine the probable binding conformation.

Design, synthesis, in silico and in vitro evaluation of thiophene derivatives: A potent tyrosine phosphatase 1B inhibitor and anticancer activity.

A series of novel methyl 4-(4-amidoaryl)-3-methoxythiophene-2-carboxylate derivatives were designed against the active site of protein tyrosine phosphatise 1B (PTP1B) enzyme using MOE.2008.10. These molecules are also subjected for in silico toxicity prediction studies and considering their corresponding drug scores, it implied that, the molecules are promising as anticancer agents. The designed compounds were synthesized by using suitable methods and characterized. They were subjected to inhibitory activity against PTP1B and in vitro anticancer activity by MTT assay. Most of the tested compounds showed potent inhibitory activity against PTP1B, among the compounds tested, compound 5b exhibited the highest activity (IC50=5.25µM) and remarkable cytotoxic activity at 0.09µM of IC50 against the MCF-7 cell line. In addition to this, compound 5c also showed potential anticancer activity at 2.22µM of IC50 against MCF-7 and 0.72µM against HepG2 cell lines as well as PTP1B inhibitory activity at IC50 of 6.37µM.

Active site directed docking studies: synthesis and pharmacological evaluation of cis-2,6-dimethyl piperidine sulfonamides as inhibitors of acetylcholinesterase.

Hypocholinergic function associated with Alzheimer's disease (AD) is well-accepted hypothesis, in this regard, many research attempts have been made to elevate the reduced cholinergic neurotransmission, among them two main treatment strategies were widely explored, namely stimulation of muscarinic receptor 1 and/or reversible inhibition of acetylcholinesterase (AChE) enzyme. In an attempt to improve the efficacy and to minimize general side effects of these AChE inhibitors, many lead molecules are developed in research; one among them is piperidine derivative. Donazepil is a widely prescribed AChE inhibitor which displays a piperidine ring in its structure. In the present study, we have docked cis-2,6-dimethyl piperidine sulfonamides (3a-i) on AChE enzyme and synthesized by nucleophilic substitution reaction between cis-2,6-dimethyl piperidine and alkyl/aryl sulfonyl chlorides in the presence of triethylamine. These piperidine sulfonamides were subjected to in vitro AChE enzyme inhibition studies and in vivo antiamnesic study to reverse scopolamine induced memory loss in rats. Two derivatives (3a and f) in this class of piperidines (3a-i) showed considerable inhibition against different sources of AChE in vitro and reduced average number of mistakes done by wistar rats as compared to scopolamine treated group in vivo (rodent memory evaluation).

Synthesis and screening for acetylcholinesterase inhibitor activity of some novel 2-butyl-1,3-diaza-spiro[4,4]non-1-en-4-ones: derivatives of irbesartan key intermediate.

The association of bioactive nucleus with other pharmacological agents is hoped to improve the efficacy of the treatment by combining the effects of different pharmacological mechanisms of action. Keeping this in view, a series of 2-butyl-1,3-diaza-spiro[4,4]non-1-en-4-one derivatives have been synthesized by interaction of 2-butyl-1,3-diaza-spiro[4,4]non-1-en-4-one with different bioactive aralkyl halides in presence of powdered potassium carbonate by two different methods viz., conventional and microwave irradiation. The yields under conventional and microwave irradiation methods were in the range of 60-65% and 80-90%, respectively. The structure elucidation of the new compounds has been carried out with the help of elemental analysis and spectral data. All the synthesized compounds have been screened for their efficacy as acetylcholinesterase (AChE) inhibitor. AChE inhibitory activity study was carried out by using Ellman colorimetric assay with neostigmine as a reference standard against targets from different species, such as pure electric eel AChE, human serum AChE, and rat brain AChE. Among the compounds synthesized, compounds 5a, 5b, 5j showed good inhibition against AChE.

Chemistry and structural evaluation of different phospholipase A2 inhibitors in arachidonic acid pathway mediated inflammation and snake venom toxicity.

PLA2 inhibitors specific to Group I and II PLA2 isoforms are therapeutically important as anti-inflammatory molecules and against venom toxicity. From various natural sources diversified molecules with PLA2 inhibition and concomitant neutralization of inflammatory reactions and venom toxicity were characterized. Using these molecules, lead compounds are generated in several laboratories. Analogues of lead molecules were generated by substituting different types of functional groups in order to obtain a molecule with optimal PLA2 inhibition. The lead molecules characterized as PLA2 inhibitors are indoles, azetidinones, piperazines, isoxazolidines, isoxazolines, diazepinones, acenaphthenes and several substrate analogues. The lead optimization involves relative hydrophobicity and substitution of functional groups, such as electron withdrawing or donating. Many such groups are placed on hydrophobic moiety and their positional bioisosters are characterized. Among these analogue piperazine derivatives on optimization with respect to hydrophobicity and electronegativity showed inhibition at nanomolar levels. Structural analysis of many lead molecules indicated that a PLA2 inhibitor should have both hydrophobic moiety and polar functional groups. Each lead molecule requires optimization in this regard for effective inhibition.

Synthesis and in vitro antimicrobial studies of medicinally important novel N-alkyl and N-sulfonyl derivatives of 1-[bis(4-fluorophenyl)-methyl]piperazine.

A series of novel substituted 1-[bis(4-fluorophenyl)-methyl]piperazine derivatives (4a-g) and (5h-m) have been synthesized. The synthesized compounds were characterized by IR and 1H NMR. All the synthesized compounds were evaluated in vitro for their efficacy as antimicrobial agents against representative strains of Gram-positive (Staphylococcus aureus ATCC 25953, Streptococcus pneumoniae ATCC 49619, Bacillus cereus 11778, and Bacillus subtilis 6051) and Gram-negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2853, Proteus vulgaris ATCC 2853, and Salmonella typhi ATCC 9484) by paper disc diffusion and microdilution methods. Among the newly synthesized compounds 4e, 5l, and 5m showed potent antimicrobial activities, when compared to the standard drug.

Synthesis and efficacy of 1-[bis(4-fluorophenyl)-methyl]piperazine derivatives for acetylcholinesterase inhibition, as a stimulant of central cholinergic neurotransmission in Alzheimer's disease.

The cholinergic hypothesis of Alzheimer's disease (AD) has spurred the development of numerous structural classes of compounds with different pharmacological profile aimed at increasing central cholinergic neurotransmission. Thus proving a symptomatic treatment for this disease are cholinomimetics with the pharmacological profile of acetyl cholinesterase (AchE) inhibitors. The novel bioactive 1-[bis(4-fluorophenyl)-methyl]piperazine derivatives were synthesized under mild conditions using different aryl/alkyl halides and heterocyclic alkyl halides with 1-[bis(4-fluorophenyl)-methyl]piperazine in the presence of powdered potassium carbonate in N,N-dimethylformamide. All the synthesized compounds were characterized by spectroscopic techniques, elemental analysis and were screened for their efficacy as AchE inhibitor. Some derivatives in this class showed good inhibition against AchE as compared to neostigmine as standard.