54558-07-5

Usage

Synthesis Reference(s)

Journal of Heterocyclic Chemistry, 11, p. 755, 1974 DOI: 10.1002/jhet.5570110518

InChI:InChI=1/C8H6N2OS/c11-8-4-3-6(9-10-8)7-2-1-5-12-7/h1-5H,(H,10,11)

Upstream product

• 52240-00-3 6-(thien-2-yl)-2,3,4,5-tetrahydropyridazin-3-one 
• 88-15-3 2-Acetylthiophene 
• 298-12-4 Glyoxilic acid 
• 87702-21-4 4-(thien-2-yl)-4-oxobutyric acid methyl ester 
• 4653-08-1 4-oxo-4-thiophen-2-yl-butyric acid 

Downstream Products

• 28657-41-2 3-chloro-6-(2'-thienyl)pyridazine 
• 75792-87-9 3-hydrazino-6-thien-2-ylpyridazine 

Relevant academic research and scientific papers

Unexpected C-C bond cleavage: A route to 3,6-diarylpyridazines and 6-arylpyridazin-3-ones from 1,3-dicarbonyl compounds and methyl ketones

An unexpected C-C bond cleavage has been revealed in the absence of metal. This observation has been exploited to develop an efficient approach toward 3,6-diarylpyridazines and 6-arylpyridazin-3-ones from simple and commercially available 1,3-dicarbonyl compounds and methyl ketones.

Endothelin receptor antagonists

This invention relates to pyridizinone derivatives of formula I STR1 wherein the various substituents are defined in the specification, and salts thereof, which have useful pharmacological properties, in particular endothelin receptor-antagonistic properties. The compounds are thus useful for the treatment of illnesses associated with endothelin activities, such as hypertension, cardiac insufficiency, coronary heart disease, renal, cerebral and myocardial ischaemia, renal insufficiency, cerebral infarct, subarachnoid haemorrhage, arteriosclerosis pulmonary high blood pressure, inflammations, asthma, prostate hyperplasia, endotoxic shock and in complications after the administration of immunosuppressants which produce renal vasoconstriction.

COUPLING OF ORGANOTIN REAGENTS WITH ARYL, ACYL AND HETEROARYL HALIDES: SYNTHESIS OF PYRIDAZINE AND QUINOXALONE DERIVATIVES

Couplin of organotin reagents Bu3SnAr (Ar = 2- or 3-thienyl, 2- or 3-pyridyl) with ClCOCH2CH2CO2Et in the presence of PdCl(CH2Ph)(PPh3)2 yields β-ketoesters ArCOCH2CH2CO2Et which were converted with hydrazine hydrate into 6-substituted 4,5-dihydropyridazin-3(2H)-ones, and thence to 3-halogeno-6-substituted pyridazines.The latter also couple under similar conditions with Bu3SnAr to yield 3-heteroarylpyridazines.With catalysts, coupling of ClCOCO2Et and Bu3SnAr proceeds with loss of carbon monoxide giving ArCO2Et, but without catalyst ArCOCO2Et is formed from which the3-heteroarylquinoxalin-3-one is prepared.The reactions of Bu3SnAr with 4-XC6H4Br (X = H,-OMe, -CN, -NO2) are also described.

PREPARATION AND REACTIONS OF SOME 2-THIENYL AND 3-THIENYL PYRIDAZINONES AND PYRIDAZINES

The preparation and reactions of some pyridazinone derivatives with 2- and 3-thienyl substituents are described.Precursor 4-oxobutanoic acids Ar2COCH2CH(Ar1)CO2H (Ar1=Pb, Ar2=2-thienyl and Ar1=2-thienyl, Ar2=Pb) were obtained by addition of HCN to the chalcones Ar1CH=CHCOAr2 followed by acid hydrolysis of the resulting nitrile.Nitriles, ArCOCH(CH3)CH2CN were prepared by the Michael-Stetter reaction and converted via the acids to the 4,5-dihydropyridazin-3(2H)-ones.Two methods wereused to obtain pyridazin-3(2H)-ones viz oxidation of the 4,5-dihydro derivatives with selenium dioxide and base-catalyzed condensation of methanal or aryl aldehydes at the 4-position of the 4,5-dihydro compound.

One-pot preparation of 6-substituted 3(2H)-pyridazinones from ketones

A one-pot process for the preparation of 6-phenyl-3(2H)-pyridazinone from acetophenone and glyoxylic acid has been investigated and shown to have wide utility in the preparation of 6- and 5,6-substituted 3(2H)-pyridazinones. Limitations to the process encountered with 2'-hydroxyacetophenone and with basic hetero-aromatic ketones have been overcome, and the processes described offer the rapid and efficient synthesis of many 6-substituted pyridazinones from readily available ketones.

Synthesis and antihypertensive activity of new 6-heteroaryl-3-hydrazinopyridazine derivatives

The synthesis and pharmacological activity of new 6-heteroaryl-3-hydrazinopyridazines with antihypertensive action are described. The introduction of pyrrole, pyrazole, imidazole, triazole, tetrazole, thiophene, indole, and carbazole heterocyclic rings into the 6 position of the pyridazine nucleus has been carried out by three different methods of synthesis. The hypotensive action has been examined on normotensive and spontaneously hypertensive rats by comparison with dihydralazine (I). 6-Imidazol-1-yl derivatives have proved particularly active. Of these derivatives 3-hydrazino-6-(2-methylimidazol-1-yl)pyridazine (7c) achieves 4.9 times the activity of dihydralazine when administered orally to spontaneously hypertensive rats. The LD50 values of 7c and dihydralazine are very similar.

6- And 8-heteroaryl-1,2,4-triazolo[4,3-b]pyridazines

This disclosure describes novel 6- and 8-heteroaryl and substituted 6- and 8-heteroaryl-1,2,4-triazolo[4,3-b]-pyridazines and their use as agents for treating anxiety.