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At least 217 records · Page 12Linked to original sources
PubMed1978

1,4-Dimorpholino-7-phenylpyrido[3,4-d]pyridazine (SD-511) as a new type of diuretic agent.

Diuretic features of 1,4-dimorpholino-7-phenylpyrido[3,4-d]pyridazine (DS-511) were studied in rats and mice. DS-511 was similar in diuretic effect to that of hydrochlorothiazide (HC) in both species, but was more water diuretic and less potassium-releasing than HC. After oral administration of DS-511 to rats the diuretic effect promptly appeared and lasted for 4 to 5 h. These patterns on onset and duration were similar to those of furosemide and acetazolamide (AZ). DS-511 was effective in experimentally induced acidotic and alkalotic rats. When DS-511 was used in combinations with other diuretics such as HC, AZ and triamterene at their maximum effective doses, urine volume and sodium excretion further increased, but potassium did not. Diuretic activity of DS-511 was not reduced by daily oral administration for 10 days to rats. In rats DS-511 reversed antidiuretic hormone (ADH)-induced antidiuresis. These findings suggest that DS-511 differs in mode and/or site of action from the known diuretics.

Acidosis↗
PubMed1995

Effects of 3-[N-(2-chlorobenzyl)amino]-6-(1H-imidazol-1-yl) pyridazine dihydrochloride on various aromatase enzyme systems and experimental breast cancer.

The effects of 3-[N-(2-chlorobenzyl)amino]-6-(1H-imidazol-1-yl)pyridazine dihydrochloride (CAS 124070-28-3, MFT-279) on various aromatase enzyme systems and experimental breast cancer were studied. MFT-279 inhibited the aromatase enzyme in vitro with an IC50 value of 2.39 nmol/l. On the other hand, MFT-279 had no effect on cytochrome P-450 dependent reactions of steroid biosynthesis. In pregnant mares' serum gonadotropin (PMSG)-treated female rats, the elevation of ovarian aromatase activity was significantly suppressed by the oral treatment with MFT-279 at 10 and 20 mg/kg. When MFT-279 (20 mg/kg) was orally given to 9,10-dimethyl-1,2-benzanthracene (DMBA)-treated female rats once a day for 28 days, regression of tumors was observed. These results suggest that MFT-279 may be useful for the endocrine therapy of hormone dependent mammary carcinoma.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

1,2,3-triazole[4,5-d]pyridazines--IV. Preparation and adenosine receptor binding of new 4 and/or 7 aminoderivatives.

This paper reports the continuation of the studies on the 4-aminosubstituted 1,2,3-triazole[4,5-d]pyridazine derivatives which had shown binding affinity towards adenosine receptors. Biological results confirmed the greater activity of a benzyl substituent in the 1 position and the receptorial stereoselectivity related to the higher and more selective A1 affinity of the 4-D(+)-alpha-methylbenzylamino enantiomer 1b. The 4-phenylhydrazino substituent has shown an interesting binding activity about equipotent towards A1 and A2 receptorial sites. A surprisingly elevated A1 affinity (Ki = 7 nM), 440 fold higher than A2 affinity, is presented by compound 1d, bearing a m-toluidino substituent.

Animals↗
PubMed1994

1,2,3-Triazole[4,5-d]pyridazines--II. New derivatives tested on adenosine receptors.

This paper reports the synthesis and biological evaluation towards A1 and A2 adenosine receptors of new 1,2,3-triazole[4,5-d]pyridazines bearing lipophilic substituents in the 1 position. Some 1-benzyl-4-substituted amino derivatives were prepared and the cyclohexylamino-, anilino- and p-toluidino- derivatives showed an interesting moderately selective activity on the A1 receptor.

Animals↗
PubMed1994

Synthesis, benzodiazepine receptor affinity and anticonvulsant activity of 5-H-indeno[1,2-c]pyridazine derivatives.

Title compounds 1-36 were synthesized by reacting hydrazine with aldol adducts obtained from ninhydrin and methyl or alpha methylene ketones and aldehydes. Some of them showed a low, but significant benzodiazepine receptor affinity whose variation was interpreted through a structure-activity relationships study based on qualitative correlations and Comparative Molecular Field Analysis (CoMFA). Some indeno-pyridazine derivatives were found to possess an interesting anticonvulsant activity which however does not seem simply related to the benzodiazepine receptor modulation.

Animals↗
PubMed1994

1,2,3-triazole[4,5-d]pyridazines. III--Synthesis of new 4-amino derivatives and their affinity toward adenosine receptors.

This paper describes the preparation and adenosine receptor binding of new 1-benzyl-4-aminosubstituted-1,2,3-triazole[4,5-d]pyridazines and of other 4-aminoderivatives bearing in the 1 position other neutral substituents. The synthetic procedures consist of nucleophilic displacement reactions from the 4-chloro derivative (procedure 1), of displacement of O-sililated intermediates (procedure 2) and of the use of phosphorus pentoxide-triethylamine hydrochloride reagent (procedure 3). The A1 adenosine receptor affinity is confirmed for the 1-benzyl substituted compounds bearing in the 4 position an arylamino or cycloalkylamino group. In addition, the compound obtained by reaction with racemic alpha-methylbenzylamine shows an interesting A1 activity, unlike the 4-benzylamino derivative.

Amines↗
PubMed1977

[Research on heterocyclic compounds. VI. Imidazo(1,2-b)pyridazine derivatives].

The preparation of a group of imidazo[1,2-b]pyridazin-2-carboxylic and -2-acetic acids is reported. The ethyl esters of these acids were prepared by reaction of some 3-aminopyridazines with ethyl bromopyruvate or 4-bromoacetoacetate. The acids were obtained by hydrolysis of the corresponding esters, and their anti-inflammatory activity was tested.

Acetates↗
PubMedDate not supplied

1,2,3-Triazolo [4,5-d] pyridazines--V. Preparation and adenosine receptor binding of new 4-amino derivatives.

This paper reports the continuation of studies on the 4-aminosubstituted 1,2,3-triazolo [4,5-d] pyridazine derivatives which had shown binding affinity towards A1-adenosine receptors. 1-Benzyl derivatives bearing new amines and new 1-(substituted benzyl) derivatives were prepared and tested. The biological results showed that some compounds possessed high affinity (approximately 30-70 nM) and good selectivity toward the A1-adenosine receptors. Further information about structure-biological activity relationships was aquired.

Animals↗
PubMedDate not supplied

[The reaction of 3-(R-phenyl)-6-hydrazine pyridazine with 5-methylisatin and 1-morpholinomethyl-5-methylisatin].

This paper presents the synthesis of six hydrazones obtained by treating 5-methyl-isatin or 1-morpholino methyl-5-methyl-isatin with 3-(R-phenyl)-6-hydrazino-pyridazine (R = OCH3, Cl, Br) and two complex combination with copper, derived from 3-(p-anisyl-pyridazinyl)-hydrazone-5-methyl-indoline-2- one. The structure of the new compounds was confirmed by the results of the quantitative elementary and IR, UV-VIS spectral analysis. The biological tests point out that product VI, in which a copper atom binds two molecules of 3-(p-anisyl-pyridazinyl)-hydrazono-5-methyl-indoline-2-one, has a considerable antiinflammatory activity, giving a inflammation inhibition of 39, 6%. All the synthetized compounds have a moderate antimicrobial activity against Candida albicans.

Animals↗
PubMed2000

Encoded Helical Self-Organization and Self-Assembly into Helical Fibers of an Oligoheterocyclic Pyridine - Pyridazine Molecular Strand.

The conformational information of an oligoheterocyclic strand containing a repeating pyridine - pyridazine codon self-organizes into a helical molecular unit, which subsequently self-assembles into helical fibers and macrofibers in dichloromethane and pyridine. The spontaneous formation of helical structures is based on a general self-organization process enforced by the conformational information encoded within the molecular strand itself.

Journal Article↗
PubMed2001

A meso-helical coordination polymer from achiral dinuclear [Cu2(H3CCN)2(micro-pydz)3][PF6]2 and 1,3-bis(diphenylphosphanyl)propane-synthesis and crystal structure of 1 to infinity Cu(mu-pydz)2][PF6 (pydz=pyridazine).

Reaction of achiral [Cu2(H3CCN)2(mu-pydz)3][PF6]2 (1) (pydz = pyridazine) with bidendate 1,3-bis(diphenylphosphanyl)propane (2) in acetonitrile at room temperature in a 1:1 ratio yielded the mononuclear copper(I) complex [Cu[CH2(CH2PPh2)2]2][PF6] (3) together with new one-dimensional coordination polymer 1 to infinity[[Cu(mu-pydz)2][PF6]] (4). Air-sensitive single crystals of 4, suitable for X-ray structure determination, were grown from a mixture of dichloromethane/ hexane [crystal system: monoclinic; space group: C2/c: a = 21.910(3), b = 12.130(2), c = 25.704(3) A,beta = 110.08(10) degrees, V = 6416.65(16) A3]. The one-dimensional coordination polymer 1 to infinity[[Cu(mu-pydz)2][PF6]] (4) exhibits as outstanding feature the rare structure of a meso-helix.

Journal Article↗
PubMed2002

Synthesis and stereochemistry of dispiro substituted pyridazines: application of ellipticity-absorbance ratio spectra for proving enantiomeric relationship by HPLC-CD/UV detection.

The aim of our study was to synthesize vinylic and pyrido-fused pyridazines with a spirano moiety and to investigate their stereochemistry by spectroscopic and HPLC analyses. The vinylic compounds 5 were obtained by Knoevenagel condensation of cyclohexylidene malonates 1 with pyridazinecarbaldehyde 2. Compound 5b exhibits geometric isomerism identified by NMR, HPLC, and X-ray methods. The thermal rearrangement reactions of compounds 5 easily led to the pyridopyridazine derivatives 6. In the case of 6b, possessing both central and axial chirality, both diastereomers and the respective enantiomers were detected. Their stereochemical relationships could be determined by HPLC-CD/UV analyses with application of anisotropy spectra in a novel way.

Journal Article↗
PubMed2003

The toxic and anti-feedant activity of 2H-pyridazin-3-one-substituted 1,3,4-oxadiazoles against the armyworm Pseudaletia separata (Walker) and other insects and mites.

The toxicities and anti-feedant activities of thirteen asymmetrical 1,3,4-oxadiazoles containing a 2H-pyridazin-3-one group were investigated. The compounds were shown to possess considerable activity in retarding the development of larvae of a number of Lepidoptera, but they were all inactive against Homoptera, Diptera and Acarina. The compounds had powerful anti-feedant activity comparable with that of azadirachtin. The toxic symptoms of the poisoned larvae indicated that the compounds were novel insect growth regulators with a mode of action that might be similar to the chitin-synthesis inhibition of oxadiazole compounds and/or the juvenile hormone effect of pyridazinone compounds.

Animals↗
PubMed2006

Nucleosides with self-complementary hydrogen-bonding motifs: synthesis and base-pairing studies of two nucleosides containing the imidazo[4,5-d]pyridazine ring system.

Synthesis and base-pairing studies of two 2'-deoxyribonucleosides, containing a common heterocyclic base, 7(4)-amino-5(6)H-imidazo[4,5-d]pyridazin-4(7)one (1 and 2), have been reported. The synthesis was accomplished by base-promoted deoxyribosylation of ethyl 5(4)-cyanoimidazole-4(5)-carboxylate (6), followed by ring-closure with hydrazine hydrate. The 1H NMR-based base-pair studies were conducted using DMF-d7 as a solvent by measuring changes in chemical shifts of the amino, hydrazide, imidazole H-2, and the sugar H-1' protons of the nucleosides with variations in concentrations and temperatures. Large downfield chemical shifts were observed for the NH, NH2, and to a lesser extent for the H-1' protons when the temperature was lowered from 25 to 0 degrees C, and then further down to -50 degrees C in 10 degree intervals. The observed experimental data are consistent with the results of molecular modeling studies. Nucleoside 2 exhibited low level antiviral activity against HIV-1 in CEM-SS cells with an IC50 of 89.2 microM. No cellular toxicity was observed at the highest concentration of the compound tested.

Anti-HIV Agents↗
PubMed2003

Redox-adaptable copper hosts. Pyridazine-linked cryptands accommodate copper in a range of redox States.

A series of structurally characterized copper complexes of two pyridazine-spaced cryptands in redox states + (I,I), (II,I), (II), (II,II) are reported. The hexaimine cryptand L(I) [formed by the 2 + 3 condensation of 3,6-diformylpyridazine with tris(2-aminoethyl)amine (tren)] is able to accommodate two non-stereochemically demanding copper(I) ions, resulting in [Cu(I)(2)L(I)](BF(4))(2) 1, or one stereochemically demanding copper(II) ion, resulting in [Cu(II)L(I)()](BF(4))(2) 3. Complex 3 crystallizes in two forms, 3a and 3b, with differing copper(II) ion coordination geometries. Addition of copper(I) to the monometallic complex 3 results in the mixed-valence complex [Cu(I)Cu(II)L(I)](X)(3) (X = PF(6)(-), 2a; X = BF(4)(-), 2b) which is well stabilized within this cryptand as indicated by electrochemical studies (K(com) = 2.1 x 10(11)). The structurally characterized, octaamine cryptand L(A), prepared by sodium borohydride reduction of L(I), is more flexible than L(I) and can accommodate two stereochemically demanding copper(II) ions, generating the dicopper(II) cryptate [Cu(II)(2)L(A)](BF(4))(4) 4. Electrochemical studies indicate that L(A) stabilizes the copper(II) oxidation state more effectively than L(I); no copper redox state lower than II,II has been isolated in the solid state using this ligand.

Journal Article↗
PubMed2006

One-pot cyclizations of dilithiated oximes and hydrazones with epibromohydrin. Efficient synthesis of 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and oxazolo[3,4-b]pyridazin-7-ones.

The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.

Journal Article↗