Pyridazines and their Benzo Derivatives

A Facile Microwave Assisted One‐pot Strategy for the Synthesis of Bis‐hexahydroquinazolin‐5(6H)‐ones

“…Thus, the infrared spectra of 2a-h showed strong peaks in the range of 1427 to 1619 cm -1 due to highly delocalised double bonds and carbonyl group stretching frequencies of enaminone functionalities. In the 1 H NMR spectra of 2a & 2e the NCH 2 protons of ethylene chain appeared as singlets at 2.83 ppm and 2.93 ppm respectively whereas the NCH 2 …”

Pyridazine derivatives and related compounds, part 8: Synthesis of different heterocycles from 3-hydrazinopyridazine

“…The reaction of the hydrazine 1 with phenyl isothiocyanate in boiling ethanol afforded thiocarbamoylhydrazine 2, while in boiling butanol afforded, unexpectedly, a single product. The isolated product was proven to be identical with 6,7,8-triphenyl-2,3-dihydro- [1,2,4]triazolo [4,3-b]pyridazine-3-thione 3. The latter compound was unequivocally prepared following the reported procedure [2], by refluxing 1 with carbon disulfide.…”

“…The isolated product was proven to be identical with 6,7,8-triphenyl-2,3-dihydro- [1,2,4]triazolo [4,3-b]pyridazine-3-thione 3. The latter compound was unequivocally prepared following the reported procedure [2], by refluxing 1 with carbon disulfide. Mechanistically, the formation of the bicyclic compound 3 from 1 involves the initial formation of 2 which undergoes immediate intramolecular nucleophilic attack of ring-2 nitrogen on the thione group with elimination of the phenylamino group.…”

“…Also a good deal of importance is being given to pyrazole, triazole, and their derivatives due to their wide use in medicinal chemistry [2]. Hence, it was thought that incorporation of the latter heterocyclic moieties into pyridazines moiety might modify their biologiCorrespondence to: A.…”

2- (3, 4- Dimethylphenyl - 3- [3, 4-Dichloro (or 3, 4-Dimethyl) Benzoyl])-Propanoic Acids as Precursors in the Synthesis of Some Heterocyclic Compounds

“…The growing number of papers describes the development of several pyridazine-based drugs and pharmacological tools (5) , drugs acting on the cardiovascular system (6)(7)(8)(9) , as agrochemicals (10) and wide range of biological action (11) . Several studies indicate that (NH) group adjacent to (C=O) group in the azine system may be an essential structural requirement in the binding of 3(2H)-pyridazinones to a variety of biological receptors (12) . Although all structural studies on this nucleus have been shown that 3(2H) pyridazinone exist in keto form (13) , but they involve ambident rings that possess a tautomeric form which is lack regio control as in the products 9 &11.…”