Some pyridazinone and phthalazinone derivatives and their vasodilator activities

An overview of pyridazin-3(2H)-one: a core for developing bioactive agents targeting cardiovascular diseases and cancer

Cardiovascular diseases (CVDs) and cancer are the top two leading causes of death globally. Vasodilators are commonly used to treat various CVDs. In cancer treatment, targeted anticancer agents have been developed to minimize side effects compared with traditional chemotherapy. Many hypertension patients are more prone to cancer, a case known as reverse cardio-oncology. This leads to the search for drugs with dual activity or repurposing strategy to discover new therapeutic uses for known drugs. Recently, medicinal chemists have shown great interest in synthesizing pyridazinone derivatives due to their significant biological activities in tackling these critical health challenges. This review will concentrate on pyridazin-3(2H)-one-containing compounds as vasodilators and anticancer agents, along with a brief overview of various methods for their synthesis.

Carbene-catalyzed enantioselective annulation of dinucleophilic hydrazones and bromoenals for access to aryl-dihydropyridazinones and related drugs

4,5-Dihydropyridazinones bearing an aryl substituent at the C6-position are important motifs in drug molecules. Herein, we developed an efficient protocol to access aryl-dihydropyridazinone molecules via carbene-catalyzed asymmetric annulation between dinucleophilic arylidene hydrazones and bromoenals. Key steps in this reaction include polarity-inversion of aryl aldehyde-derived hydrazones followed by chemo-selective reaction with enal-derived α,β-unsaturated acyl azolium intermediates. The aryl-dihydropyridazinone products accessed by our protocol can be readily transformed into drugs and bioactive molecules.

Polarity inversion of arylidene hydrazones to react with bromoenals via carbene organic catalysis is disclosed. The reaction enantioselectively affords 6-aryl-4,5-dihydropyridazinones and related drugs with proven commercial applications.

Ultrasound-promoted regio and chemoselective synthesis of pyridazinones and phthalazinones catalyzed by ionic liquid [bmim]Br/AlCl3

The first ultrasound-promoted multicomponent synthesis of pyridazinones and phthalazinones from arenes, cyclic anhydrides and ArNHNH(2) in the presence of an efficient recyclable catalyst, [bmim]Br/AlCl(3), in high yield and short reaction time is reported.

Synthesis and Spectral Characterisation of Some Phthalazinone Derivatives

1,2,4-Triazol-3-yl, 1,3,4-oxadiazol-2-yl, 1,3-dioxoisoindolin-2-yl, 1 H-pyrazol-4-yl, phthalazin-1(2 H)one, 5 H-2,3-benzodi-azepine-1,4-dione and pyridazine-1,4-dione derivatives were prepared via the reaction of the readily obtainable starting material 1-oxo-1,2-dihydrophthalazin-4-carbohydrazide with one carbon donor like phenyl isothiocyanate, phenyl isocyanate, triethylorthoformate, formic acid and different electrophilic reagents such as anhydrides, chromen-1,3-dione, chloroacetyl chloride, acetic anhydride, arylidene malononitrile, ethoxymethylene malononitrile and ethyl acetoacetate.

Synthesis and Antibacterial and Antifungal Studies of Novel Nitrogen Containing Heterocycles from 5-Ethylpyridin-2-ethanol

A novel series of chalcones, pyrimidines and imidazolinone is described; chalcones (4a-o) were prepared from the lead molecule 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde. Pyrimidine (5a-o) derivatives were prepared from the reaction of chalcones and guanidine nitrate in alkali media. Imidazolinones (6a-o) were synthesized from reaction of pyrimidine and oxazolone derivatives (prepared by Erlenmeyer azlactone synthesis). The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, (1)H and (13)C NMR spectral data. All the products were screened against different strains of bacteria and fungi. Most of these compounds showed better inhibitory activity in comparison to the standard drugs.

A facile synthesis of pyridazinone derivatives under ultrasonic irradiation

A new, efficient and general method for preparation of N-substituted-pyridazinones using ultrasound irradiation is reported. Under ultrasound the reaction time decreases substantially, the yields are high and the reaction conditions are mild. It was noticed that substituents at the 3-(6)-position of pyridazone heterocycle have a substantial influence on the reactivity, while the effect of the substituents at the 1-(2)-position seems to be of minor importance. A comparative study of the reactions performed under ultrasound conditions versus at room temperature has been done.

Pyridazinone derivatives: design, synthesis, and in vitro vasorelaxant activity

In an attempt to identify potential vasodilator-cardiotonic lead compounds, three series of pyridazinones were designed using three-dimensional pharmacophore developed with CATALYST software from a set of potent cyclic nucleotide phosphodiesterase III, cAMP PDEIII inhibitors. The features of the target compounds were based on the structures of many biologically active lead compounds with cAMP phosphodiesterase III inhibiting activity such as Milrinone and others. Compounds with higher fit scores to the developed pharmacophore were synthesized namely; 6-(3-ethoxycarbonyl-4-oxo-1,4-dihydroquinolin-6-yl)-4,5-dihydro-3(2H)-pyridazinones (3a and 3b), 6-[4-(2,6-disubstituted-quinolin-4-ylamino)phenyl]-4,5-dihydropyridazin-3(2H)-ones (5a-f), and 6-[3-(5-cyano-6-oxo-4-aryl-1,6-dihydro-2-pyridyl)phenylamino]-3(2H)pyridazinone (8a and 8b). The vasodilator activity of the newly synthesized compounds was examined on the isolated main pulmonary artery of the rabbit. Some of the tested compounds showed moderate vasorelaxant activity compared with standard drug, Milrinone.

Vasorelaxant activity of phthalazinones and related compounds

Several series of dihydrostilbenamide, imidazo[2,1-a]isoindole, pyrimido[2,1-a]isoindole and phthalazinone derivatives were obtained and their vasorelaxant activity was measured on isolated rat aorta rings pre-contracted with phenylephrine (10(-5)M). Some phthalazinones attained, practically, the total relaxation of the organ at micromolar concentrations. For the most potent compound 9h (EC(50)=0.43microM) the affinities for alpha(1A), alpha(1B) and alpha(1D) adrenergic sub-receptors were determined.

Some pyrrole substituted aryl pyridazinone and phthalazinone derivatives and their antihypertensive activities

In this work, some 2-nonsubstituted/2-methyl-/2-(2-acetyloxyethyl)-6-[4-(substituted pyrrol-1-yl)phenyl]-4,5-dihydro-3(2H)-pyridazinone, derivatives and 2-nonsubstituted/2-methyl- 4-[4-(substituted pyrrol-1-yl)phenyl]-1(2H)-phthalazinone derivatives were synthesised by reacting hexan-2,5-dion or 1-aryl-3-carbethoxypent-1,4-diones with corresponding 2-substituted/nonsubstituted 6-(4'-aminophenyl)-4,5-dihydro-3(2H)-pyridazinone or 2-substituted/nonsubstituted-4-(4'-aminophenyl)-(2H)-phthalazinone under Paal-Knorr pyrrole synthesis conditions. The antihypertensive activities of the compounds were examined both in vitro and in vivo. Some pyridazinone derivatives showed appreciable activity.