A rapid, one-pot, four-component route to 2H-indazolo[2,1-b]phthalazine-triones

One-pot synthesis of polyhydropyridine derivatives via Hantzsch four component condensation in water medium: Use of a recyclable Lewis acid [Ce(SO₄)₂.4H₂O] catalyst

“…Green chemistry approaches are significant due to the reduction in by-products and waste produced, and lowering of energy costs. The possibility of performing multi-component reactions under green solvent conditions with a heterogeneous catalyst could enhance their efficiency from an economic as well as ecological point of view [21][22][23][24]. In this regard, a new, simple, mild and efficient method for the one-pot synthesis of 1,4-dihydropyrimidine derivatives is reported herein.…”

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

“…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. However, these methods have limitations such as the use of toxic metals, toxic organic solvents, expensive or large amounts of catalysts, and tedious work-up procedures.…”

H4SiW12O40 Catalyzed One‐Pot Synthesis of 12‐Aryl‐8,9,10,12‐tetrahydrobenzo[a] Xanthen‐11‐ones Under Solvent‐Free Conditions

“…Moreover, solvent-free reactions often provide clean, efficient and high-yielding organic processes in heterocyclic synthesis 28 . In continuation of our efforts to develop new, green chemistry methods [29][30][31] , we describe herein a clean and convenient synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo [a] xanthen-11-ones by three-component condensation reaction of 2-naphthol, aromatic aldehydes, and dimedone using catalytic amount of tungstosilicic acid as a recyclable catalyst under solvent-free conventional heating conditions (Scheme 1) 15-40 min. …”