Phosphatase CDC25B Inhibitors Produced by Basic Alumina-Supported One-Pot Gram-Scale Synthesis of Fluorinated 2-Alkylthio-4-aminoquinazolines Using Microwave Irradiation

A literature review on pharmacological aspects, docking studies, and synthetic approaches of quinazoline and quinazolinone derivatives

Quinazoline and quinazolinone derivatives piqued medicinal chemistry interest in developing novel drug candidates owing to their pharmacological potential. They are important chemicals for the synthesis of a variety of physiologically significant and pharmacologically useful molecules. Quinazoline and quinazolinone derivatives have anticancer, anti-inflammatory, antidiabetic, anticonvulsant, antiviral, and antimicrobial potential. The increased understanding of quinazoline and quinazolinone derivatives in biological activities provides opportunities for new medicinal products. The present review focuses on novel advances in the synthesis of these important scaffolds and other medicinal aspects involving drug design, structure-activity relationship, and action mechanisms of quinazoline and quinazolinone derivatives to help in the development of new quinazoline and quinazolinone derivatives.

Synthesis of benzo[b][1,5]diazocin-6(5H)-one derivatives via the Cu-catalysed oxidative cyclization of 2-aryl-1H-indoles with 1,1-enediamines

A novel protocol for the synthesis of highly functionalized benzo[b][1,5]diazocin-6(5H)-one derivatives (BDCOs, 4 and 5) from 2-aryl-1H-indoles and 1,1-enediamines was developed via a complex cascade of reactions including regioselective free radical oxidation, the 1,2-addition of imine, imine-enamine tautomerization, intramolecular cyclization, and ring expansion. The cascade reaction was enabled by refluxing a mixture of two substrates in the presence of di-tert-butyl peroxide (DTBP) as an oxidant and anhydrous CuI as a catalyst in toluene under argon protection. Consequently, a series of BDCOs (4 and 5) were synthesized with high regioselectivity in good yield. This protocol can be used for the synthesis of functionalized BDCOs via a one-pot oxidative annulation reaction rather than a multi-step reaction, which is suitable for both combinatorial and parallel syntheses of BDCOs.

A Review on Current Synthetic Methods of 4-Aminoquinazoline Derivatives

Quinazoline scaffold and its various derivatives, as an important category of heterocyclic compounds, have received much attention for the design and development of new drugs due to their various pharmacological properties like anticancer, anticonvulsant, antidepressant, antibacterial, antifungal, antioxidant, anti-HIV, antileishmanial, anticoccidial, antimalarial, anti-inflammatory, antileukemic, and antimutagenic. Among the various substituted quinazolines, 4-aminoquinazoline scaffold, as a privileged structure in medicinal chemistry, is present in many approved drugs and biologically active compounds. Furthermore, 4-aminoquinazoline derivatives are often applied as key intermediates in the preparation of bioactive compounds. The current review focuses on the key methods for the preparation of 4-aminoquinazoline derivatives, including the nucleophilic substitution reaction, metal-catalyzed approaches, microwave irradiation methods, cyclocondensation, and direct amination methods.

Design, synthesis, in silico and biological evaluations of novel polysubstituted pyrroles as selective acetylcholinesterase inhibitors against Alzheimer's disease

The objective of this study was to design new polysubstituted pyrrole derivatives as selective acetylcholinesterase (AChE) inhibitors to target Alzheimer's disease. In this context, a highly efficient, one-pot, sequential, multi-component synthesis of a diverse range of polysubstituted pyrroles was developed through a sequential domino strategy by the condensation of amines with 1,1-bis(methylthio)-2-nitroethene (BMTNE), Knovenagle reaction of arylglyoxals with malono derivatives and subsequent Michael addition and intramolecular cyclization reaction in EtOH at reflux. Thirty-nine synthesized compounds were evaluated as AChE and butyrylcholinesterase (BChE) inhibitors. Among the synthesized compounds, compound 4ad (IC₅₀ = 2.95 ± 1.31 µM) was the most potent and selective AChE inhibitor with no significant inhibition against butyrylcholinesterase BChE. A kinetic study of 4ad revealed that this compound inhibited AChE in an uncompetitive mode. Based on a molecular modeling study, compound 4ad due to its small size properly fitted into the active site of AChE compared to BChE and stabilized by H-bond and hydrophobic interactions with the critical residues of the AChE binding pocket. Consequently, it was proposed that the 4ad derivative can be an ideal lead candidate against AD with a simple and practical operation of synthetic procedures.

Application of Azide-Tetrazole Tautomerism and Arylsulfanyl Group Dance in the Synthesis of Thiosubstituted Tetrazoloquinazolines

Nucleophilic aromatic substitution reaction between 4-aryl­thio-2-chloroquinazolines and NaN3 takes place with an unusual sulfanyl group dance and leads to the formation of 5-(arylthio)tetrazolo[1,5-c]-quinazolines, which do not form the azide tautomer and do not undergo CuAAC reactions with alkynes. On the other hand, 5-azidotetrazolo[1,5-a]quinazoline (formally described as 2,4-diazidoquinazoline) undergoes regioselective nucleophilic aromatic substitution with thiols at C5 and forms 5-(alkyl/arylthio)tetrazolo[1,5-a]quinazolines, the structure of which has been proved by X-ray crystallography. The latter exist in tautomeric equilibrium with their 2-azidoquinazoline form, which provides possibility for copper-catalyzed azide–alkyne 1,3-dipolar cyclo­addition reaction, leading to the 4-alkyl/arylthio-2-(1H-1,2,3-triazol-1-yl)quinazolines.

An Environmentally Benign Cascade Reaction of 1,1-Enediamines (EDAMs) for Site-Selective Synthesis of Highly Functionalized 2,10-Dihydro-1H-imidazo[1',2':1,6]pyrido[2,3-b]indoles and Pyrroles

A novel protocol for the synthesis of pyrido[2,3-b]indoles (α-carbolines, 3) from (E)-3-(2-oxo-2-phenylethylidene) indolin-2-one derivatives 1 and 1,1-enediamine (EDAM) 2a via an unexpected cascade reaction in ethanol was developed. Pyrido[2,3-b]indole derivatives 4 were obtained by the same reaction, albeit by stirring the mixture for a longer period of time (about 48 h). As a result, two kinds of functionalized α-carbolines 3 and 4 were synthesized by the facile reaction of the (E)-3-(2-oxo-2-phenylethylidene)indolin-2-one derivatives and 2-(nitromethylene)imidazolidine under basic conditions (Cs₂CO₃) in ethanol. In addition, a diverse array of EDAM substrates (2b-2k) were tested in this reaction to afford the expected target compounds 5. This protocol is suitable for the combinatorial and parallel syntheses of natural-like products, including highly functionalized α-carbolines and pyrroles, especially 2-oxoindolin-3-yl pyrroles. This approach features several advantages, such as being a simple and practical operation (requiring only filtration and washing without column chromatography), furnishing excellent yields (72-98%), and producing diverse libraries of target compounds with potential biological activities.

Microwave-Assisted Synthesis of Quinazolines and Quinazolinones: An Overview

Microwave irradiation (MWI), as a unique, effective, sustainable, more economic, and greener source of energy compared to conventional heating, is applied in different organic transformations to result in the rapid formation of desired compounds due to thermal/kinetic effects. In this review, we try to underscore the applications of microwave irradiation (MWI) in the synthesis of quinazoline and quinazolinone derivatives that have been achieved and reported on in the last two decades.

Multicomponent Cascade Reaction by Metal-Free Aerobic Oxidation for Synthesis of Highly Functionalized 2-Amino-4-coumarinyl-5-arylpyrroles

A novel approach has been constructed for the synthesis of two types of 2-amino-4-coumarinyl-5-arylpyrroles (ACAPs, 5 and 6) through a cascade reaction and a metal-free catalyzed aerobic oxidation reaction of arylglyoxal monohydrates 1, 1,1-enediamines (EDAMs) 2 and 3, and 4-hydroxy-2H-chromen-2-ones 4 via multicomponent reactions to produce the target compounds with good to excellent yields. Specifically, hydroxyl-substituted 2-amino-4-coumarinyl-5-arylpyrroles, that is, 2-amino-4-coumarinyl-5-aryl-6-hydroxylpyrroles (ACAHPs) 6, were obtained by metal-free aerobic oxidation in 1,4-dioxane at simple reflux for approximately 10 h. As a result, ACAHPs 6 have been produced without metal catalysts or traditional oxidizing agents. This method represents a route to obtain the novel ACAPs in an environmentally friendly, concise, rapid, and practical manner with potential biological activity of the product.