Novel diphenylalkyl piperazine derivatives with dual calcium antagonistic and antioxidative activities

Chemistry of 2-(Piperazin-1-yl) Quinoline-3-Carbaldehydes

Abstract:

This review described the preparation of 2- chloroquinoline-3-carbaldehyde derivatives 18 through Vilsmeier-Haack formylation of N-arylacetamides and the use of them as a key intermediate for the preparation of 2-(piperazin-1-yl) quinoline-3-carbaldehydes. The synthesis of the 2- (piperazin-1-yl) quinolines derivatives was explained through the following chemical reactions: acylation, sulfonylation, Claisen-Schmidt condensation, 1, 3-dipolar cycloaddition, one-pot multicomponent reactions (MCRs), reductive amination, Grignard reaction and Kabachnik-Field’s reaction.

Insight into antimicrobial activity of substituted phenylcarbamoyloxypiperazinylpropanols

3-[4-(Substituted)phenyl-/4-(diphenylmethyl)phenylpiperazin-1-yl]-2-hydroxypropyl-1-[(substituted)phenyl]carbamates and their salts with hydrochloric acid were synthesized, characterized, and tested in vitro against Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 as reference and quality control strains, against three methicillin-resistant isolates of S. aureus, and three isolates of vancomycin-resistant E. faecalis. All the compounds were evaluated against Mycobacterium tuberculosis H₃₇R_a/ATCC 25177, M. kansasii DSM 44162, and M. smegmatis ATCC 700084. All of the tested compounds demonstrated very good activity against all the tested strains/isolates comparable with or better than that of clinically used drugs (ampicillin, ciprofloxacin, vancomycin, isoniazid). 1-[{(3-Trifluoromethyl)phenyl}carbamoyloxy-2-hydroxypropyl]-4-(3,4-dichlorophenyl)piperazin-1-ium chloride demonstrated the highest potency against all the tested strains/isolates (MICs ranged from 3.78 to 30.2 µM), and 1-[{(3-trifluoromethyl)phenyl}carbamoyloxy-2-hydroxypropyl]-4-(diphenylmethyl)piperazin-1-ium chloride was the most effective against all the screened mycobacterial strains (MICs ranged from 3.64 to 14.5 µM). All the investigated derivatives had strong antibiofilm activity against S. aureus ATCC 29123 and a synergistic or additive effect with gentamicin against isolates of E. faecalis with both intrinsic and acquired resistance to gentamicin. The screening of the cytotoxicity of the compounds was performed using human monocytic leukemia THP-1 cells. The IC₅₀ values of the most effective compounds ranged from ca. 2.8 to 7.3 µM; thus, it can be stated that the antimicrobial effect is closely connected with their cytotoxicity. These observations disqualify these compounds from further development as antimicrobial agents, but they can be considered potential multi-target drugs with a preferred anticancer effect with good water solubility and additional anti-infectious activity.

Synthesis and characterization of a disubstituted piperazine derivative with T-type channel blocking action and analgesic properties

Background

T-type calcium channels are important contributors to signaling in the primary afferent pain pathway and are thus important targets for the development of analgesics. It has been previously reported that certain piperazine-based compounds such as flunarizine are able to inhibit T-type calcium channels. Thus, we hypothesized that novel piperazine compounds could potentially act as analgesics.

Results

Here, we have created a series of 14 compound derivatives around a diphenyl methyl-piperazine core pharmacophore. Testing their effects on transiently expressed Cav3.2 calcium channels revealed one derivative (3-((4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)methyl)-4-(2-methoxyphenyl)-1,2,5-oxadiazole 2-oxide, compound 10e) as a potent blocker. 10e mediate tonic block of these channels with an IC50 of around 4 micromolar. 10e also blocked Cav3.1 and Cav3.3 channels, but only weakly affected high-voltage-activated Cav1.2 and Cav2.2 channels. Intrathecal delivery of 10e mediated relief from formalin and complete Freund’s adjuvant induced inflammatory pain that was ablated by genetic knockout of Cav3.2 channels.

Conclusions

Altogether, our data identify a novel T-type calcium channel blocker with tight structure activity relationship (SAR) and relevant in vivo efficacy in inflammatory pain conditions.

Manganese(ii) chloride catalyzed highly efficient one-pot synthesis of propargylamines and fused triazoles via three-component coupling reaction under solvent-free condition

A one-pot green and highly efficient method for the synthesis of propargylamines and distereoselective synthesis of fused triazoles via three-component coupling in the presence of manganese(ii) chloride and a catalyst-free 1,3-dipolar cycloaddition reaction without using a co-catalyst is reported.

Acaricidal properties of piperazine and its derivatives against house-dust and stored-food mites

BACKGROUND

Piperazine derivatives possess pharmacological properties, yet the acaricidal activity of these compounds has not been investigated. This study was conducted to evaluate the colour alteration and acaricidal activity of piperazine derivatives against Dermatophagoides spp. and Tyrophagus putrescentiae (Schrank) using filter paper and fumigant methods.

RESULTS

In a fumigant bioassay, 1-phenylpiperazine (7.83 microg cm(-2)) against D. farinae (Hughes) was found to be 4.7 times more toxic than DEET (36.84 microg cm(-2)), followed by benzyl benzoate (9.72 microg cm(-2)), piperazine (11.41 microg cm(-2)), 1-ethoxycarbonylpiperazine (20.14 microg cm(-2)) and 1-(2-methoxyphenyl)piperazine (22.14 microg cm(-2)). In a filter paper bioassay, 1-(2-methoxyphenyl)piperazine (3.65 microg cm(-2)) was 5.7 times more toxic than DEET (20.64 microg cm(-2)), followed by 1-ethoxycarbonylpiperazine (4.02 microg cm(-2)), 1-phenylpiperazine (4.75 microg cm(-2)), benzyl benzoate (7.83 microg cm(-2)) and piperazine (10.59 microg cm(-2)). Similar results have been exhibited with piperazine derivatives against D. pteronyssinus (Troussart). However, no activity against T. putrescentiae was observed for piperazine derivatives, except for piperazine.

CONCLUSIONS

These results indicate that piperazine derivatives may be suitable as vapour-phase acaricide fumigants owing to their high volatility, acaricidal activity and safety. 1-Phenylpiperazine was found to be an excellent mite indicator based on the colour change it induced. Taken together, these findings indicate that piperazine derivatives may be used to replace existing problematical acaricides owing to their activity and ability to act as a mite indicator.

Synthesis and antimicrobial activity of N-alkyl and N-aryl piperazine derivatives

A series of substituted piperazine derivatives have been synthesized and tested for antimicrobial activity. The antibacterial activity was tested against Staphylococcus aureus (MTCCB 737), Pseudomonas aeruginosa (MTCCB 741), Streptomyces epidermidis (MTCCB 1824) and Escherichia coli (MTCCB 1652), and antifungal activity against Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger. All synthesized compounds showed significant activity against bacterial strains but were found to be less active against tested fungi. In vitro toxicity tests demonstrated that compounds 4d and 6a showed very less toxicity against human erythrocytes.

Antioxidative activities of novel diphenylalkyl piperazine derivatives with high affinities for the dopamine transporter

A new series of diphenylalkyl piperazine derivatives with high affinities for the dopamine transporter (DAT), which were modified at both the diphenylalkyl moiety and the phenyl ring in the phenylamino moiety of 1-[4,4-bis(4-fluorophenyl)butyl]-4-[2-hydroxy-3-(phenylamino)propyl]piperazine 1, was evaluated for their inhibitory activities against auto-oxidative lipid peroxidation in canine brain homogenates. Some of these were approximately equivalent in activity to alpha-tocopherol as a potent antioxidant with IC(50) values of low micromolar order, and the 4-hydroxyphenyl derivative 11 showed the most potent antioxidative activity with an IC(50) value of 0.32 microM, exhibiting approximately 5-fold more potent activity than alpha-tocopherol. The structure-activity relationship (SAR) studies of the antioxidative activity of these derivatives are presented.

Enantioselective chromatography and molecular modeling of novel aryloxyaminopropan-2-ols with the alkyl carbamate function

A series of different racemic aryloxyaminopropan-2-ol derivatives 1a-d-3a-d with potential beta-adrenergic blocking effects related to propanolol 4 and atenolol 5 was resolved by HPLC using Chiralcel OD-H and Chiralpak AD as chiral stationary phases. Mobile phases consisted of a hexane/alcohol (propan-2-ol or ethanol) mixture doped with a modifier (DEA or TFA). The retention behavior of the compounds depended on the position of the carbamate attached to the aryloxy moiety and on the length of the alkyl residue in the carbamate. Enantiomers of the title compounds were baseline separated with the separation factors alpha and resolutions R(s) varying in the range of 1.34-4.55 and 1.50-10.65, respectively. The chromatographic systems developed can be used for the determination of the enantiomeric purity of the title compounds. Molecular modelling using empirical molecular mechanics and ab initio quantum chemistry methods provided low-energy structures in which sites of potential interactions responsible for retention behavior and chiral recognition could be identified.

Syntheses of novel diphenyl piperazine derivatives and their activities as inhibitors of dopamine uptake in the central nervous system

A new series of diphenyl piperazine derivatives containing the phenyl substituted aminopropanol moiety, which were modified at sites between the diphenyl and piperazine moieties, was prepared and evaluated for dopamine transporter binding affinity with [(3)H]GBR12935 in rat striatal membranes. These synthesized compounds showed apparent dopamine transporter binding affinities (IC(50)<30 nM) and some of them were approximately equivalent in activity to GBR12909 known as a potent dopamine uptake inhibitor, showing the activities with IC(50) values of nanomolar range. Among them, 1-[4,4-bis(4-fluorophenyl)butyl]-4-[2-hydroxy-3-(phenylamino)propyl]piperazine 2 was evaluated for extracellular dopamine levels in rat striatum using in vivo brain microdialysis. The intraperitoneal administration of 2 (0.01, 0.03, or 0.1 mmol/kg) induced dose-dependent increases of dopamine levels in rat striatal dialysates. The maximum increases in dopamine levels induced by 2 were greater than those by GBR12909. The pharmacological data of these novel diphenyl piperazine derivatives show that the compounds have potent dopamine uptake inhibitory activities in the central nervous system.