A “One Pot,” Environmentally Friendly, Multicomponent Synthesis of 2‐Amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines and Their Antimicrobial Activity

Abstract

A series of multifunctional 2‐amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines (4a, 4b, 4c, 4d, 4e, 4f) was synthesized by multicomponent reaction of 3‐formylindole (1), cyanoethylacetate (2), and guanidine hydrochloride (3) with NaOH by using green chemical techniques, viz. microwave irradiation and grindstone technology. The same reactants when refluxed in ethanol also gave titled compounds (4a, 4b, 4c, 4d, 4e, 4f). Compared with conventional procedure, the reaction can be carried out under milder conditions, requiring a shorter reaction time and giving higher yields following the green chemistry methodology. All the synthesized compounds have been characterized on the basis of elemental analyses and spectral data (IR, 1H NMR, 13C NMR, and mass). All synthesized compounds were also evaluated for their antimicrobial activity against nine pathogenic bacteria, antifungal activity against Rhizopus stolonifer, Aspergillus flavus, and Fusarium oxysporum and antibacterial activity against Escherichia coli and Pseudomonas aeruginosa at different concentrations. Most of the compounds showed mild to moderate activity.

Chemical Waltz of Organic Molecules “On Water”: Saline-Assisted Sustainable Regioselective Synthesis of Fluorogenic Heterobioconjugates via Click Reaction

“…Inspired by recent reports on bio-orthogonal chemistry exploiting weakly or nonfluorescent reagents to produce highly fluorescent molecules, which could be exploited for tagging of biomolecules in living systems, especially in aqueous medium, − and in continuation to our previous work on fluorescent coumarin-based compounds, − herein, we describe a green protocol for the preparation of heterobioconjugate-based 1,4-disubsituted 1,2,3-traizoles through a 1,3-dipolar cycloaddition reaction using NaCl as a salting-out agent in water under ultrasonic irradiation at ambient temperature. Additional advantage of this protocol is recycling of the traditional Cu­(I) catalytic system up to seven cycles, which enhances the viability of this method by reducing the loading of toxic Cu.…”

Recent advances in the application of indoles in multicomponent reactions

“…A one-pot three-component reaction of indole-3-aldehyde derivatives 1, ethyl cyanoacetate 6, and guanidine hydrochloride 69 under three different conditions, including microwave irradiation, grindstone technology and reux, was developed to afford 2-amino-5-cyano-4-[(2-aryl)-1H-indol-3-yl]-6-hydroxypyrimidines 70 (Scheme 26) 86 The products 70 were evaluated for their antimicrobial activity against nine pathogenic bacteria and showed mild to moderate activity.…”

Synthesis and Antiviral Bioactivity of Novel 2‐Substituted Methlthio‐5‐(4‐Amino‐2‐Methylpyrimidin‐5‐yl)‐1,3,4‐Thiadiazole Derivatives

“…The IR spectrum of 9a-9v displayed absorption bands between 3371.5 and 3089.9 cm À1 corresponding to N-H, 1639.4-1423.4 cm À1 corresponding to C¼C and C¼N function. The 1 H-NMR spectrum of 9b in DMSO-d 6 displayed a triplet at δ 1.41 ppm and a multiplet at δ 3.23-3.25 ppm that corresponds to S-CH 2 CH 3 functionality, a singlet at δ 2.43 ppm integrating for three protons was assigned to methyl protons of pyrimidine-CH 3 . A singlet that appeared at δ 8.06 ppm was observed because of the protons of NH 2 group.…”

“…Pyrimidine ring system is very important because several of its derivatives have been found to be medicinally useful. Synthetic studies of fused pyrimidines have been reported extensively because of their structural diversity, associated with a wide spectrum of biological activity including insecticidal , acaricidal , fungicidal , antimicrobial , herbicidal , antiviral , and anticanceral activity . In the ambit of application in antiviral area, many pyrimidine derivatives with good anti‐tobacco mosaic virus (TMV) activity have been described.…”