PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Piperazines”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2004

Synthesis and structure-activity relationships of indole and benzimidazole piperazines as histamine H(4) receptor antagonists.

We describe the structure-activity relationships for a series of ligands structurally related to the recently identified (5-chloro-1H-indol-2-yl)-(4-methyl-piperazin-1-yl)-methanone (1) as histamine H(4) receptor (H(4)R) antagonists. Furthermore, we identified related benzimidazoles as novel lead compounds for the H(4)R. The ligands have been evaluated by radioligand displacement studies and functional assays for their interaction with both the human histamine H(3) and H(4) receptors and exhibit pK(i) values up to 7.5 at the human H(4)R.

Benzimidazoles↗
PubMed2005

Synthesis and antimalarial evaluation of new N1-(7-chloro-4-quinolyl)-1,4-bis(3-aminopropyl)piperazine derivatives.

Synthesis and evaluation of the activity of new N(1)-(7-chloro-4-quinolyl)-1,4-bis(3-aminopropyl)piperazine derivatives against a chloroquine-resistant strain of Plasmodium falciparum are described. Selectivity indices were improved for two compounds versus the lead 1, the bis-cyclopropylmethyl derivative, thus increasing the therapeutic interest of our family. As our previous studies conducted on the mode of action of our compounds made us hypothesize the existence of original mechanisms and/or original targets, terminal amino derivatives can be considered as promising tools further mechanistical studies, as probes for affinity chromatography.

Animals↗
PubMed2005

Melanocortin subtype-4 receptor agonists containing a piperazine core with substituted aryl sulfonamides.

The biological activity for a set of melanocortin-4 receptor (MC4R) agonists containing a piperazine core with an ortho-substituted aryl sulfonamide is described. Compounds from this set had binding and functional activities at MC4R less than 30 nM. The most selective compound in this series was >25,000-fold more potent at MC4R than MC3R, and 490-fold more potent at MC4R than MC5R. This compound also reduced food intake after oral dosing at 25, 50, and 100 mg kg(-1) in fasted mice.

Animals↗
PubMed2005

Surfing the piperazine core of tricyclic farnesyltransferase inhibitors.

In order to fully explore structure-activity relationships at the 1- and 2-positions of the piperazine core of tricyclic farnesyltransferase inhibitors, an 11,718-member ECLiPS library was synthesized and screened in a farnesyltransferase scintillation proximity assay. A detailed description of the library and analyses of the screening data will be provided.

Enzyme Inhibitors↗
PubMed2006

BACE-1 inhibitory activities of new substituted phenyl-piperazine coupled to various heterocycles: chromene, coumarin and quinoline.

The protease beta-secretase plays a central role in the synthesis of pathogenic amyloid-beta in Alzheimer's disease. Here, we report a new series of analogues based on the phenyl-piperazine scaffold coupled to various heterocyclic moieties, which demonstrate improved inhibitory activities on BACE-1 (FRET assay) compared to already known naphthyl counterparts. The obtained results suggest further structural modifications to access to more potent BACE-1 inhibitors.

Amyloid Precursor Protein Secretases↗
PubMed2006

Synthesis and antibacterial activity of new fluoroquinolones containing a substituted N-(phenethyl)piperazine moiety.

N-(Phenethyl)piperazinyl quinolone derivatives that bear a methoxyimino-substituent have been synthesized and evaluated for antimicrobial activity against Gram-positive and Gram-negative microorganisms. In addition, to define structure-activity relationships, ciprofloxacin derivatives containing 2-oxo-2-phenylethyl or 2-hydroxyimino-2-phenylethyl moieties at N-4 position of piperazine ring were prepared and tested. Ciprofloxacin derivatives, containing a N-(chloro-substituted phenethyl) residue, showed in vitro Gram-positive and Gram-negative activity generally comparable or superior to that of reference quinolones.

Anti-Bacterial Agents↗
PubMed2004

Piperazine-linked bisbenzamidines: a novel class of antileishmanial agents.

A series of 13 1,4-diarylpiperazines has been prepared, evaluated for antileishmanial activity and their binding affinity to DNA was measured. Among these compounds, 1,4-bis[4-(1H-benzimidazol-2-yl)phenyl]piperazine (14) emerged as the most active compound with an IC(50) value of 0.41 microM which is about sevenfold more potent than pentamidine.

Animals↗
PubMed2006

Synthesis, characterization and in vitro biological studies of novel cyano derivatives of N-alkyl and N-aryl piperazine.

Cyano derivatives of N-alkyl and N-aryl piperazine have been synthesized and screened for antibacterial and antifungal activities. All the synthesized compounds showed the antibacterial activity against pathogenic strains of Staphylococcus aureus (MTCCB 737), Pseudomonas aeruginosa (MTCCB 741), Streptomyces epidermidis (MTCCB 1824) and Escherichia coli (MTCCB 1652) and antifungal activity against pathogenic strains of Aspergillus fumigatus (ITCC 4517), Aspergillus flavus (ITCC 5192) and Aspergillus niger (ITCC 5405). All compounds showed mild to moderate antimicrobial activity. However, compounds 3c, 4a and 6 showed potent antibacterial activity against pathogenic strains used in the study. Compounds 3a, 3b, 4b, and 4d showed mild to moderate antifungal activity against Aspergillus pathogenic strains. The compounds reported in this study were assessed for there cytotoxicity using MTT colorimetric assay on Hela cells. All the compounds showed cell viability more than the control drug gentamicin, with compound 2 having highest i.e. 95% cell viability.

Acetonitriles↗
PubMed2006

Synthesis and evaluation of novel 1-(1H-1,2,4-triazol-1-yl)-2-(2,4-difluorophenyl)-3-[(4-substitutedphenyl)-piperazin-1-yl]-propan-2-ols as antifungal agents.

A series of 1-(1H-1,2,4-triazol-1-yl)-2-(2,4-difluorophenyl)-3-[(4-substitutedphenyl)-piperazin-1-yl]-propan-2-ols have been designed and synthesized on the basis of the structure-activity relationships and antimycotic mechanism of azole antifungal agents. Their structures were confirmed by elemental analysis, IR, MS, (1)H NMR and (13)C NMR. Results of preliminary antifungal tests against six human pathogenic fungi (Candida albicans, Candida parapsilosis, Cryptococcus neoformans, Candida tropicalis, inherently fluconazole-resistant Candida krusei, Candida glabrata) in vitro showed that all title compounds exhibited activity against fungi tested to some extent except against C. tropicalis. Compound 5b showed higher activity against C. albicans, C. parapsilosis and C. krusei than fluconazole, and its MIC values were determined to be 0.5microg/mL, 1microg/mL and 4microg/mL, respectively. Compound 5k showed higher activities against Torulopsis glabrata than fluconazole (with the MIC value of 2microg/mL). Compounds 5a, 5c, 5f, 5g, 5i exhibited higher activities against C. parapsilosis than fluconazole (with the MIC values of 2microg/mL, 2microg/mL, 2microg/mL, 1microg/mL and 2microg/mL, respectively).

Antifungal Agents↗
PubMed2005

Synthesis and biological evaluation of new thiazolyl/benzothiazolyl-amides, derivatives of 4-phenyl-piperazine.

A series of thiazolyl-N-phenyl piperazines has been synthesised and tested for anti-inflammatory activity. Their R(M) values were determined as an expression of their lipophilicity. Theoretical calculation of their lipophilicity, as clog P and logPsk also performed. The effect of the synthesised compounds on inflammation, using the carrageenin induced mouse paw oedema model was studied. In general, the studied compounds were found to be potent anti-inflammatory agents (44-74.1%). Anti-inflammatory activity was influenced by some structural characteristics of the synthesised compounds. An attempt was made to correlate their biological activity with some physicochemical parameters using a quantitative structure-activity relationship approach (QSAR).

Amides↗
PubMed2005

Development of simultaneous gas chromatography-mass spectrometric and liquid chromatography-electrospray ionization mass spectrometric determination method for the new designer drugs, N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP) and their main metabolites in urine.

To prove the intake of recently controlled designer drugs, N-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP), a simple, sensitive and reliable method which allows us to simultaneously detect BZP, TFMPP and their major metabolite in human urine has been established by coupling gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). GC-MS accompanied by trifluoroacetyl (TFA) derivatization and LC-MS analyses were performed after the enzymatic hydrolysis and the solid phase extraction with OASIS HLB, and BZP, TFMPP and their major metabolites, 4'-hydroxy-BZP (p-OH-BZP), 3'-hydroxy-BZP (m-OH-BZP) and 4'-hydroxy-TFMPP (p-OH-TFMPP), have found to be satisfactorily separated on a semi-micro SCX column with acetonitrile-40 mM ammonium acetate buffer (pH 4) (75:25, v/v) as the eluent. The detection limits produced by GC-MS were estimated to be from 50 ng/ml to 1 microg/ml in the scan mode, and from 200 to 500 ng/ml in the selected ion monitoring (SIM) mode. Upon applying the LC-ESI-MS technique, the linear calibration curves were obtained by using the SIM mode for all analytes in the concentration range from 10 ng/ml to 10 microg/ml. The detection limits ranged from 5 to 40 ng/ml in the scan mode, and from 0.2 to 1 ng/ml in the SIM mode. These results indicate the high reliability and sensitivity of the present procedure, and this procedure will be applicable for proof of intake of BZP and TFMPP in forensic toxicology.

Animals↗
PubMed2006

Comparative investigation of N,N'-bis-(dithiocarboxy)piperazine and diethyldithiocarbamate as precipitants for Ni(II) in simulated wastewater.

The performances of a coordination polymerization precipitant, N,N'-bis-(dithiocarboxy)piperazine (BDP) were compared with the widely used heavy metal precipitant, diethyldithiocarbamate (DDTC), through the treatment of three kinds of nickel-containing wastewaters, NiSO(4), nickel citrate (NiCA) and Ni(2+)-dye. Results indicated that both BDP and DDTC at their stiochiometric doses could reduce 50.00 mg l(-1) free nickel(II) to lower than 1.0 mg l(-1) (discharge limit of nickel ions in China) and 10% precipitants doses increase could treat NiCA containing 50.00 mg l(-1) Ni(2+) to meet the discharge limit. But [NiBDP](n) coordination polymerization precipitates had more rapid settling speed than Ni(DDTC)(2) precipitates. It was also observed that BDP could still partly remove Reactive Brilliant Red X-3B from Ni(II)-dye integrated wastewater through the adsorption of the precipitates [NiBDP](n), in addition to precipitating Ni(II). A 1:1 stiochiometric dose of BDP/Ni(II) could decrease Ni(II) from 50.00 to 0.87 mg l(-1), and simultaneously reduce the dye from 30.00 to 19.52 mg l(-1).

Adsorption↗
PubMed2005

2-[4-(3,4-Dimethylphenyl)piperazin-1-ylmethyl]-1H benzoimidazole (A-381393), a selective dopamine D4 receptor antagonist.

2-[4-(3,4-Dimethylphenlyl)piperazin-1-ylmethyl]-1H benzoimidazole (A-381393) was identified as a potent dopamine D4 receptor antagonist with excellent receptor selectivity. [3H]-spiperone competition binding assays showed that A-381393 potently bound to membrane from cells expressing recombinant human dopamine D4.4 receptor (Ki=1.5 nM), which was 20-fold higher than that of clozapine (Ki=30.4 nM). A-381393 exhibited highly selective binding for the dopamine D4.4 receptor (>2700-fold) when compared to D1, D2, D3 and D5 dopamine receptors. Furthermore, in comparison to clozapine and L-745870, A-381393 exhibits better receptor selectivity, showing no affinity up to 10 microM for a panel of more than 70 receptors and channels, with the exception of moderate affinity for 5-HT2A (Ki=370 nM). A-381393 potently inhibited the functional activity of agonist-induced GTP-gamma-S binding assay and 1 microM dopamine induced-Ca2+ flux in human dopamine D4.4 receptor expressing cells, but not in human dopamine D2L or D3 receptor cells. In contrast to L-745870, A-381393 did not exhibit any significant intrinsic activity in a D4.4 receptor. In vivo, A-381393 has good brain penetration after subcutaneous administration. A-381393 inhibited penile erection induced by the selective D4 agonist PD168077 in conscious rats. Thus, A-381393 is a novel selective D4 antagonist that will enhance the ability to study dopamine D4 receptors both in vitro and in vivo.

Animals↗
PubMed2005

In vivo evaluation of [123I]-4-iodo-N-(4-(4-(2-methoxyphenyl)-piperazin-1-yl)butyl)-benzamide: a potential sigma receptor ligand for SPECT studies.

In this study, in vivo evaluation in mice and rabbits of [123I]-4-iodo-N-(4-(4-(2-methoxyphenyl)-piperazin-1-yl)butyl)-benzamide ([123I]-BPB), a potential radioligand for visualisation of the sigma receptor by single photon emission computed tomography (SPECT), is reported. The compound possesses appropriate lipophilicity (log P=2.2) and binds sigma-1 and sigma-2 receptors (pKi=6.51 and 6.79, respectively). In mice, this new radioiodinated tracer exhibited high brain uptake (4.99% ID/g tissue at 10 min postinjection) and saturable binding (3.06% ID/g tissue at 10 min postinjection) as determined by pretreatment with unlabeled [123I]-BPB. A metabolite study demonstrated no (less than 5%) labeled metabolites in the brain. In rabbits, regional brain distribution was investigated and the tracer displayed high, homogeneous central nervous system uptake. Selectivity was assessed by competition experiments with known sigma ligands. Metabolite analysis showed no (less than 8%) labeled metabolites in the rabbit brain. In conclusion, our findings indicate that [123I]-BPB is not a suitable tracer for visualisation of D3 receptors while its potential for sigma receptor imaging is severely hampered by its affinity for dopamine receptors.

Animals↗
PubMed1997

Specific binding of 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenyl propyl) piperazine (GBR-12935), an inhibitor of the dopamine transporter, to human CYP2D6.

The binding of [3H]1-[2-(diphenylmethoxy)ethyl]-4-(3-phenyl propyl) piperazine (GBR-12935), an antagonist of the dopamine transporter, to human P450s expressed in yeast cells was investigated. Among the ten forms of human P450 tested (CYP1A1, 1A2, 2A6, 2B6, 2C8, 2C9, 2C18, 2D6, 2E1, and 3A4), [3H]GBR-12935 bound most strongly to CYP2D6. The calculated Kd of [3H]GBR-12935 binding to CYP2D6 was 42.2 nM, indicating that GBR-12935 has a high affinity for CYP2D6. The characteristics of [3H]GBR-12935 binding to CYP2D6 were investigated by competitive studies using several chemicals. The binding of [3H]GBR-12935 to CYP2D6 was not changed by dopamine, suggesting that these binding sites are not dopamine-sensitive binding sites. The binding of [3H]GBR-12935 to CYP2D6 was decreased partially by substrates or inhibitors of CYP2D isoforms (quinine, quinidine, propranolol, bufuralol, imipramine, and desipramine). By means of binding studies using several forms of expressed human P450, we demonstrated that the CYP2D isoform is one GBR-12935 binding site that is insensitive to dopamine.

Carrier Proteins↗
PubMed1997

Determination of trazodone and its metabolite, 1-m-chlorophenyl-piperazine, in human plasma and red blood cell samples by HPLC.

OBJECTIVES: To develop an HPLC method for the analysis of trazodone and its metabolite, 1-m-chlorophenyl-piperazine (m-CPP), in human plasma and red blood cells. DESIGN AND METHODS: The analytes were extracted by heptane containing 1.5% isoamyl alcohol, back extracted into phosphoric acid and analyzed by reverse phase HPLC with UV detection. RESULTS: In seven randomly selected, male, human subjects plasma concentrations (nmol/l) were 380-5841 for trazodone and 14-237 for m-CPP while those in packed red blood cells were 98-634 for trazodone and 15-155 for m-CPP. Plasma trazodone concentrations were 4-11-fold higher than those in red blood cells while those of m-CPP were about equal. This may be the first report on concentrations of trazodone and m-CPP in human red blood cells. CONCLUSIONS: This sensitive method can be used for monitoring trazodone and m-CPP in human plasma and red blood cells.

Adult↗