1H and 13C NMR Study of 1-Hydrazino-2,3-dihydro-1H-pyrazolo[1,2-a]pyridazine-5,8-diones and -1H-pyrazolo[1,2-b]phthalazine-5,10-diones and Their Ring-Chain Tautomerism

Abstract

Treatment of 1-hydroxy-2,3-dihydro-1H-pyrazolo[1,2-a]pyridazine-5,8-diones and -1H-pyrazolo[1,2-b]phthalazine-5,10-diones with hydrazides produces corresponding acylhydrazino derivatives. In this work, ten new hydrazino derivatives were synthesized, and their properties were studied by 1 H and 13 C NMR spectroscopy. These compounds exhibited several types of structural variation, including ring-chain tautomerism, cis-trans isomerism with respect to the substituents in the pyrazole ring, and (E)/(Z) rotamerism with respect to the nitrogen−carbon hydrazide bond with partial double-

A green and efficient method for the synthesis of homodimeric (β-dicarbonyl) arylmethanes and dihydropyridine from dimedone in water

“…Homodimeric (β-dicarbonyl) arylmethane derivatives have attracted considerable attention since they exhibit potent bioactivity, like anti-inflammatory, antibiotic and anti-oxydant principle [1][2][3]. Several syntheses have been developed for the preparation of these homodimeric compounds.…”

An Efficient Three Component Synthesis of 1H-Indazolo[2, 1-b]phthalazine-triones Catalyzed by Orthophosphoric Acid in Water-Phenol System

“…Amongst, nitrogen heterocyclic containing a phthalazine moiety was reported to possess anticonvulsant 10 , cardiotonic 11 , vasorelaxant 12 antimicrobial 13 , anti-inflammatory 14 , antifungal 15 and anticancer 16,17 activities. Newly, three-RESEARCH ARTICLE component reactions of dimedone (5,5- 23 , N-halo sulphonamides 24 , silica supported poly phosphoric acid 25 , 26 Mg(HSO 4 ) 2 , phosphor sulfonic acids 27 , nano silica sulphuric acid 28 , sulfonated polyethylene glycol 29 and boron sulfonic acid 30 .…”

β-Cyclodextrine-SO3H: the most efficient catalyst for one-pot synthesis of 2H-indazolo[2,1-b]phthalazine-triones under solvent-free conditions

“…Heterocycles containing phthalazine moiety constitute as an important structural motif attributing to their pharmacological and biological activities [4,5]. Besides these they are endowed with anticonvulsant [6], cardio tonic [7] and vasorelaxant activities [8] and also comply as anti-inflammatory, analgesic, antihypoxic and antipyretic agents [9]. Numerous protocols have been developed for the synthesis of 3,4-dihydro-1H-indazolo [1,2-b]phthalazine-1,6,11(2H,13H)-triones using p-TSA [10], ionic liquids [11], (S)-CSA [12], dodecylphosphonic acid (DPA) [13], heteropoly acids [14], Ce(SO 4 ) 2 Á4H 2 O [15], solid acids [16], montmorillonite K-10 [17], N-halosulfonamides [11], silicasulfuric acid [18], phosphomolybdic acid-silica (PMA-SiO 2 ) [19] as catalysts.…”