A highly flexible green synthesis of 1H-pyrazolo[1,2-b]phthalazine- 5,10-dione derivatives with CuI nanoparticles as catalyst under solvent-free conditions

CuI nanoparticles as an efficient catalyst have been used for the preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones by the four-component condensation reaction of phthalic anhydride, hydrazine monohydrate, aromatic aldehydes and malononitrile or ethyl cyanoacetate under solventfree conditions in good to excellent yields, short reaction times and environmentally benign, milder reaction conditions.     

One-pot four-component synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives

The synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives by NiCl₂-catalyzed novel one-pot four-component condensation reaction of phthalimide, hydrazine, malononitrile (or ethyl cyanoacetate), and aromatic aldehydes was reported. This work provides a simple, efficient, and eco-friendly method for the construction of pyrazolo[1,2-b]phalazine-5,10-dione derivatives.     

Electrocatalytic multicomponent assembling of phthalhydrazide,aldehydes and malononitrile: An efficient approach to 1H-pyrazolo[1,2-b]phthalazine-5,10-diones

Electrocatalytic multicomponent transformation of phthalhydrazide, aromatic aldehydes and malononitrile in n-propanol in an undivided cell in the presence of sodium bromide as an electrolyte leads to 1H-pyrazolo[1,2-b]phthalazine-5,10-diones in short reaction times (4–8 min) and high yields (85–98%) at room temperature. The developed efficient electrocatalytic approach to the corresponding 1H-pyrazolo[1,2-b]phthalazine-5,10-diones is beneficial from the viewpoint of diversity-oriented large-scale processes and represents a new example of the ecologically pure synthetic concept for electrocatalytic multicomponent reactions strategy.     

Efficient and convenient synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives mediated by L-proline

An efficient, four-component, one-pot condensation reaction of phthalimide or phthalic anhydride, aromatic aldehydes, and ethyl cyanoacetate for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives mediated by L-proline in excellent yields is reported.     

Silica-supported tungstic acid (STA): A recyclable catalyst for the synthesis of 1H-indazolo [1,2-b]phthalazine-trione and spiro-triazolo[1,2-a]indazole-tetraone derivatives under solvent-free condition

Abstract

An efficient one-pot synthesis of 1?H-indazolo[1,2-b]phthalazine-trione and spiro-triazolo[1,2-a]indazole-tetraone derivatives via three-component condensation reaction of phthalhydrazide or 4-phenylurazole, aldehydes or isatins and dimedone in the presence of a catalytic amount of silica-supported tungstic acid (STA), as a heterogeneous solid acid catalyst under solvent-free conditions is presented. This ecofriendly protocol offers several advantages such as a cost-effective procedure with excellent yields, short reaction time, simple workup, recovery and reusability of catalyst with broad scope of usable substrates. This has made the protocol sustainable and economic.     

Zinc–proline complex as a novel and efficient catalyst for the green synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones

A simple, efficient and green approach to the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones has been developed via one-pot three-component reaction of aromatic aldehyde, malononitrile and phthalhydrazide catalyzed by zinc–proline complex (Zn[L-proline]₂) using H₂O: PEG₄₀₀?=?6: 4 as solvent. Atom economy, good to excellent yield, operational simplicity and easy workup are important features of this method.

Graphical abstract

     

β-Alanine-functionalized magnetic graphene oxide quantum dots: an efficient and recyclable heterogeneous basic catalyst for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 2,3-dihydroquinazolin-4(1H)-one derivatives

In this research, we report a novel synthesis of magnetic β-alanine-functionalized-graphene oxide quantum dots Fe₃O₄@GOQDs-N-(β-alanine) as a recyclable and eco-friendly heterogeneous nanocatalyst. The catalytic efficiency of these nanosheets was explored as a basic catalyst for a one-pot three-component synthesis of various 1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 2,3-dihydroquinazolin-4(1H)-one derivatives. The reactions proceeded smoothly under mild and green conditions to afford the respected products in excellent yields. The structure of this newly fabricated catalyst was successfully confirmed by different analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, field emission-scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, and thermogravimetric analysis. The stability and recyclability of the catalyst were examined by performing the model reaction in six consecutive runs. The recovered catalyst from the first run was directly used for the next runs with no significant loss of catalytic activity.     

A novel one-pot isocyanide-based four-component reaction: synthesis of highly functionalized 1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates and 1H-pyrazolo[1,2-a]pyridazine-1,2-dicarboxylates

A new protocol has been developed for the efficient synthesis of structurally diverse 1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates and 1H-pyrazolo[1,2-a]pyridazine-1,2-dicarboxylates via a four-component reaction of hydrazine hydrate, dialkyl acetylenedicarboxylates, isocyanides and various cyclic anhydrides such as succinic anhydride, maleic anhydride and phthalic anhydride in ethanol/acetone (1:1) at room temperature in good to moderate yields.     

Silica tungstic acid (STA) as a highly efficient and reusable catalyst for the synthesis of benzoxanthenes under solvent-free conditions in ultrasonication

An environmentally benign, ultrasound-promoted synthesis of biologically active benzoxanthene derivatives has been developed by silica-supported tungstic acid as an efficient catalyst under solvent-free conditions. The major advantages of the present protocol are operational simplicity, use of an inexpensive catalyst, bypassing the chromatographic purification, good yields, and short reaction times. The catalyst could be reused at least five consecutive cycles, without loss of its catalytic activity.     

[Bu3NH][HSO4] catalyzed: an eco-efficient synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and 2H-indazolo[2,1-b]phthalazine-triones under solvent-free conditions

Research on Chemical Intermediates - A Brønsted acidic ionic liquid [Bu3NH][HSO4] as an eco-efficient catalyst for the one-pot multicomponent synthesis of...     

Mild preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives with magnetic Fe3O4 nanoparticles coated by (3-aminopropyl)-triethoxysilane as catalyst under ambient and solvent-free conditions

An efficient, one-pot quantitative procedure for preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives from four-component condensation reaction of hydrazine monohydrate, phthalic anhydride, malononitrile or ethyl cyanoacetate, and aromatic aldehydes in the presence of magnetic Fe₃O₄ nanoparticles coated by (3-aminopropyl)-triethoxysilane as catalyst under mild, ambient, and solvent-free conditions is described. Simple procedure, high yield, short reaction time, and environmentally benign method are advantages of this protocol. The magnetic Fe₃O₄ nanoparticles coated by (3-aminopropyl)-triethoxysilane can be recovered and reused several times without loss of activity.     

A highly efficient green synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives and their photophysical studies

A task-specific ionic liquid, [Bmim]OH, has been used for an efficient synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones by one-pot cyclocondensation reaction of phthalhydrazide, aromatic aldehydes, and malononitrile or ethyl cyanoacetate under microwave irradiation. The advantages of this method include the use of green catalyst, no organic solvent, easy work-up and excellent yields. The photophysical properties for some 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives have been investigated for the first time.     

Four-Component Domino Reaction for the Synthesis of 1-(1H-Indol-2-yl)-1H-pyrazolo[1,2-b]phthalazine-5,10-diones

Facile, efficient, four-component domino reaction of dialkylphthalates, hydrazine hydrate, indole-3-carboxaldehydes, and malononitrile/ethyl cyanoacetate leads to the formation of 1-(1H-indol-2-yl)-1H-pyrazolo [1,2-b] phthalazine-5,10-diones in the presence of InCl₃ as catalyst in refluxing ethanol for 1 h in good yields. This four-component domino reaction transformation presumably proceeds via sequential addition, dehydration, condensation, and cyclization steps.     

One-pot three-component reaction of isocyanides, dialkyl acetylenedicarboxylates and phthalhydrazide: synthesis of highly functionalized 1H-pyrazolo[1,2-b]phthalazine-5,10-diones

Protonation of the highly reactive 1:1 intermediate produced in the reaction between alkyl isocyanides and electron-deficient acetylenic esters with phthalhydrazide, leads to a vinylisonitrilium cation, which undergoes an addition reaction with the conjugate base of the phthalhydrazide to produce dialkyl 3-(alkylamino)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates in fairly good yields at room temperature.     

Combining a Click–Multicomponent Reaction: One-Pot Synthesis of 1,2,3-Triazol-4-ylmethyl 3-Amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2-b]phthalazine-2-carboxylate Derivatives

(1,2,3-Triazol-4-yl)methyl-3-amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2-b]phthalazine-2-carboxylate derivatives were synthesized by a four-component, one-pot condensation reaction of benzaldehyde derivatives, an active methylene compound (prop-2-ynyl-2-cyanoacetate), azides, and phthalhydrazide in the presence of Cu(OAc)₂/sodium ascorbate as catalysts and 1-methyl-1H-imidazolium trifluoroacetate ([Hmim]TFA) as an ionic liquid medium in good to excellent yields.     

A green and convenient protocol for the synthesis of diarylmethanes via a one-pot,three-component reaction catalyzed by a novel silica tungstic acid (STA) under solvent-free conditions

A cost-effective and eco-friendly synthesis of diarylmethanes derivatives has been developed through the Mannich type Friedel–Crafts addition reaction of tertiary aromatic amine formaldehydes with β-naphthol/indole using silica-supported tungstic acid (STA) as a recyclable heterogeneous acid catalyst in solvent-free condition. Here, we proposed two schemes using the same catalyst. The effects of different solvents have been studied and a comparison of silica-supported tungstic acid with different acid catalysts has also been made.     

One-pot green synthesis of novel 5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine derivatives with eco-friendly biodegradable eggshell powder as efficacious catalyst

Research on Chemical Intermediates - An eco-friendly and efficient green protocol is developed for the synthesis of sixteen pyrazolo-phthalazine derivatives (5a–p) by using...     

Green synthesis of 1H-pyrazolo[1,2-b]phthalazine-2-carbonitrile derivatives using a new bifunctional base–ionic liquid hybrid magnetic nanocatalyst

The ionic liquid-base N,N,2,2,6,6-hexamethyl-N-(3-(trimethoxysilyl)propyl)piperidin-4-amonium iodide was grafted onto titana-coated NiFe₂O₄ nanoparticles for obtaining an efficient and reusable ionic liquid-base hybrid nanocatalyst. The structure of hybrid nanoparticles was characterized using FT-IR (Fourier-transform infrared spectroscopy), field emission scanning electron microscopy, EDS (energy-dispersive X-ray spectroscopy), EDS map scan, Brunauer–Emmett–Teller surface area analysis, CHN (elemental analysis), vibrating sample magnetometer and thermogravimetric analysis techniques. Furthermore, this novel hybrid catalyst was used in one-pot three-component synthesis of 3-amino-1-aryl-5,10-dioxo-1H-pyrazolo[1,2-b]phthalazine-2-carbonitrile derivatives under green and environmentally benign conditions. This protocol avoids the use of harmful catalysts, toxic solvents and harsh reaction conditions. The products were synthesized in excellent yields within short reaction time and identified using elemental analysis, FT-IR, ¹H NMR and ¹³C NMR spectroscopies.