Microwave-Assisted Synthesis of Arylated Pyrrolo[2,1-a]Isoquinoline Derivatives via Sequential [3 + 2] Cycloadditions and Suzuki-Miyaura Cross-Couplings in Aqueous Medium

Clean and Efficient Green Protocol of N,N'-Bis(2-(arylazo)-2-(aroyl)vinyl)ethane-1,2-diamines in Aqueous Medium without Catalyst: Synthesis and Photophysical Characterization

An interesting platform for the construction of novel N,N'-bis(2-(arylazo)-2-(aroyl)vinyl)ethane-1,2-diamines is reported in this work. These bis-arylazo compounds were assembled based on the reaction of ethylenediamine with various 2-arylhydrazono-3-oxopropanals in aqueous conditions under both conventional stirring and microwave conditions at ambient temperature. The factors affecting the optimization conditions were intensively practiced. The structures of the new products were established from their spectroscopic analyses and X-ray single crystals. The photophysical behavior of the bis-arylazo derivatives was examined. The UV-vis spectra showed maximum absorption band in the range of 348-383 nm with molar extinction coefficients ranging from 0.89 × 104 to 4.02 × 104 M-1 cm-1. The highest molar absorptivity coefficient (∼45 × 103 M-1 cm-1) was observed in CHCl3 solvent. The fluorescence properties showed that some compounds were interesting fluorophore materials with high Stokes shifts. The photoluminescence study of some compounds was promising, with maximal emission peaks ranging between 417-436 nm.

Microwave-assisted chemoselective synthesis and photophysical properties of 2-arylazo-biphenyl-4-carboxamides from hydrazonals

The reaction of 3-oxo-2-arylhydrazonopropanals with acetoacetanilide in an equimolar ratio, under DBU/1,4-dioxane/microwave irradiation reaction conditions, resulted in chemoselective formation of 4-arylazo-5-hydroxy-benzamide derivatives. The structures of the obtained biphenyl-4-carboxamides were characterized by several spectroscopic techniques including IR, 1H- and 13C-NMR, MS and HRMS, and X-ray single crystals of three examples. The photophysical properties of the new products were also evaluated, with a particular focus on their absorption and emission spectra, which provided valuable information regarding their optical properties. The new compounds emitted 513-549 nm green fluorescence in acetone solution under UV irradiation.

Efficient and Recyclable Solid-Supported Pd(II) Catalyst for Microwave-Assisted Suzuki Cross-Coupling in Aqueous Medium

Solid-supported catalysts play efficient and crucial roles in organic synthesis. A solid-supported palladium(II) complex based on chitosan was synthesized and fully characterized using all possible tools (Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectrometry, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller analysis). The catalytic activity of the solid-phase catalyst in Suzuki cross-coupling reactions was evaluated in aqueous solvents under both conventional heating and microwave irradiation conditions. The recyclability and thermal stability of the prepared catalyst were also examined, and the catalyst was found to be active till five consecutive runs without a notable loss of activity under the microwave condition, with the turnover number and turnover frequency values reaching 19,019 and 114,114 h^-1, respectively.

Solvent-Free Synthesis of Pyrrolo [2,1-α] Isoquinolines via One-Pot Four- Component Reaction

Abstract:

An efficient four-component reaction to synthesize pyrrolo [2,1-a] isoquinolines from malononitrile, aromatic aldehydes, isoquinoline, and cyclohexyl isocyanide under solvent-free conditions is described. In a convenient, simple, and efficient one-pot procedure, the domino Knoevenagel-nucleophilic cycloaddition reaction affords excellent yields of products in less than 1 h.

Asymmetric Catalytic Synthesis of Hexahydropyrrolo-isoquinolines via Three-Component 1,3-Dipolar-Cycloaddition

An asymmetric three-component 1,3-dipolar cycloaddition of 3,4-dihydroisoquinolines, bromoacetates and α,β-unsaturated pyrazole amide is realized by using a chiral N,N'-dioxide-Y(OTf)₃ complex as the catalyst. The process includes a base-promoted formation of dihydroisoquinolium ylides in situ, and a chiral Lewis acid-catalyzed asymmetric [3+2] cycloaddition with α,β-unsaturated pyrazole amides. A series of hexahydropyrrolo-isoquinolines are obtained in moderate to good yields with excellent diastereo- and enantioselectivities.

Synthesis, Antitumor Activity, Molecular Docking and DFT Study of Novel Pyrimidiopyrazole Derivatives

BACKGROUND

In this investigation, 2-cyano-N-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl) acetamide (3) reacts with dimethylformamide dimethyl acetal (DMF-DMA) to afford the corresponding (E)- 2-cyano-3-(dimethylamino)-N-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)acrylam-ide (4) utilizing microwave irradiation. The condensation reactions of acrylamide derivative 4 with hydrazine derivatives obtain pyrazole derivatives 6a and 6b; respectively. The synthesized compounds demonstrate in vitro antitumor activity against liver tumor cell line HepG2. Furthermore, additional studies were carried out on the most effective compound 6b to evaluate the potential interaction against 4hdq synthase complex with ΔE= -4.5Kcal/mol and with short distance = 1.727Å and 2.027Å, respectively. The comprehensive theoretical studies of compounds 6a and 6b is based on bond length, bond angles and energy gap HOMO-LUMO. In addition, the vibrational frequencies of optimized compounds 6a and 6b were examined through DFT/B3LYP/6+31G(d) basis set.

METHODS

In this research, synthesis of novel pyrimidiopyrazole derivatives calculated the computational studies to find suitable drug-receptor interactions and biological activity.

RESULTS AND DISCUSSION

The synthesized pyrimidiopyrazole derivative 6b exhibited high antitumor activity IC50 =12.6 μg/ml and interacted it with 4hdq synthase complex with ΔE=-4.5Kcal/mol and with short distance = 1.727Å and 2.027Å. Furthermore, the optimized compounds utilize Gaussian 09W.

CONCLUSION

In the optimized pyrimidiopyrazole derivatives, 6b showed better antitumor activity HeG-2 against 5-flurouracil due to its energy and confirmed more potent of hydrogen bond interaction with protein pocket.

Pyrrolo[2,1-a]isoquinoline scaffold in drug discovery: advances in synthesis and medicinal chemistry

Pyrrolo[2,1-a]isoquinoline (PIq) is a nitrogen heterocyclic scaffold of diverse alkaloids endowed with several biological activities, including antiretroviral and antitumor activities. Several 5,6-dihydro-PIq (DHPIq) alkaloids, belonging to the lamellarins' family, have proved to be cytotoxic to tumor cells, as well as reversers of multidrug resistance. In this review, we provide an overview of the main achievements over the last decade in the synthetic approaches to access libraries of PIq compounds along with a survey, as comprehensive as possible, of bioactivity, mechanism of action, pharmacophore and structure-activity relationships of synthetic analogs of DHPIq-based alkaloids. The focus is mainly on the potential exploitation of the (DH)PIq scaffold in design and development of novel antitumor drugs.