Silica sulfuric acid as an efficient catalyst for the preparation of 2H-indazolo[2,1-b]phthalazine-triones

Ionic Liquid 4-(3-Methyl-1-imidazolio)-1-butanesulfonic Acid Hydrogen Sulfate-catalyzed Synthesis of Phthalazinetrione Derivatives

“…The procedure was also applicable to aliphatic aldehydes, which gave satisfactory yields although longer reaction times were required in comparison with aromatic aldehydes (Table 4, entries 10 and 11). In addition, the three-component reactions using dimedone (Table 4, entries 1-9) generally gave better yields than cyclohexane-1,3-dione (Table 4, entries [12][13][14][15][16][17][18][19].…”

“…In addition, these compounds show good promise as new luminescence materials and fluorescence probes [12]. There are several methods to synthesize phthalazine derivatives, including the reaction of phthalhydrazide, aldehydes and dimedone or cyclohexane-1,3-dione catalyzed by p-TSA [13], H 2 SO 4 [14], H 4 SiW 12 O 40 [15], H 3 PW 12 O 40 [16], silica sulfuric acid [17], silicasupported polyphosphoric acid [18], TMSCl [19], phosphomolybdic acid (PMA)-SiO 2 [20], N,N,N ,Ntetrabromobenzene-1,3-disulfonamide and poly(Nbromo-N-ethylbenzene-1,3-disulfonamide) [21]. Most recently a one-pot four-component reaction for the synthesis of phthalazine derivatives was reported using Ce(SO 4 ) 2 · 4H 2 O [22] as catalyst.…”

Heteropoly Acid in Ionic Liquid - An Efficient Catalyst for the Preparation of 2H-Indazolo[2,1-b]Phthalazine-Triones

“…The combined ether extractions were dried over Na 2 SO 4 , concentrated and the residue recrystallized from ethyl acetate/n-hexane (1:3) to afford the pure product. The products 4a-4f are known compounds, and their structures were deduced by comparison of their physical and spectroscopic data with those previously reported [9][10][11][12]. …”

“…Phthalazine derivatives were reported to possess vasorelaxant [2], cardiotonic [3], and anticonvulsant [4], activities. Therefore, a number of methods have been reported in the literature for the synthesis of phthalazine derivatives [4][5][6][7][8][9][10][11]. Unfortunately, many of these processes suffer from one or other limitations such as harsh reaction conditions, low product yields, tedious workup procedures, relatively long reaction times, and cooccurrence of several side products, and difficulty in recovery and reusability of the catalysts.…”

Magnetic Nanoparticle Immobilized N-Propylsulfamic Acid as a Recyclable and Efficient Nanocatalyst for the Synthesis of 2H-indazolo[2,1-b]phthalazine-triones in Solvent-Free Conditions: Comparison with Sulfamic Acid

“…16 Although several reports on the synthesis of phthalazines fused with indazole have been published. [17][18][19][20][21][22][23][24][25][26] However, the development of an efficient and versatile method for the preparation of fused phthalazine with indazole is an active ongoing research area, and there is a potential for further improvement toward green chemistry.…”