An efficient method for the stereoselective synthesis of "all center substituted" polycyclic pyrazoles from alkynyl cyclohexa-2,5-dienones and nonstabilized diazoalkanes via sequential [3 + 2]-cycloaddition/[1,5]-sigmatropic rearrangement and aza-Michael reactions is reported. The developed process is highly regioselective and stereoselective. It employs a wide substrate scope to furnish structurally diverse linear and bridged [4.4..0] ring-fused pyrazoles in moderate to good yields. One-pot and gram-scale syntheses and synthetic transformations have also been showcased.
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http://dx.doi.org/10.1021/acs.orglett.3c03967 | DOI Listing |
Seven novel polycyclic pyrazoline and pyrazole sensors were synthesised and screened for useful photophysical properties with pyrazoline 2 and pyrazole 7, displaying an Fe "turn-off" response in aqueous environments with Fe limits of detection (LoD) of 2.12 μM and 3.41 μM, respectively.
View Article and Find Full Text PDFRSC Adv
May 2024
Department of Chemistry, Faculty of Education, Ain Shams University Cairo Egypt
A simple synthetic method was performed to design a novel series of polycyclic systems consisting of carbazole-thiazolidinone-chromone hybrids 4a-e and carbazole-thiazolidinone-pyrazole hybrids 5a-e in excellent yields. The methodology depended on the one-pot four-component reaction of 3-amino-9-ethylcarbazole, substituted isothiocyanates, ethyl bromoacetate and 6-methyl-3-formylchromone in ethanol under ultrasound waves at 50 °C to give the carbazole-thiazolidinone-chromone hybrids 4a-e. The latter isolated products were treated with hydrazine hydrate in ethanol under ultrasound waves at 50 °C affording the corresponding carbazole-thiazolidinone-pyrazole hybrids 5a-e.
View Article and Find Full Text PDFJ Org Chem
May 2024
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Polycyclic energetic materials make up a distinctive class of conjugated structures that consist of two or more rings. In this work, 1,3-bis(3,5-dinitro-1-pyrazol-4-yl)-4,6-dinitrobenzene () was synthesized and investigated in detail as a polycyclic heat-resistant energetic molecule that can be deprotonated by bases to obtain its anionic (-) salts. All compounds were thoroughly characterized by H and C NMR, infrared spectroscopy, high-resolution mass spectrometry, and elemental analysis.
View Article and Find Full Text PDFOrg Lett
February 2024
Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh 226031, India.
An efficient method for the stereoselective synthesis of "all center substituted" polycyclic pyrazoles from alkynyl cyclohexa-2,5-dienones and nonstabilized diazoalkanes via sequential [3 + 2]-cycloaddition/[1,5]-sigmatropic rearrangement and aza-Michael reactions is reported. The developed process is highly regioselective and stereoselective. It employs a wide substrate scope to furnish structurally diverse linear and bridged [4.
View Article and Find Full Text PDFPharmaceuticals (Basel)
August 2023
Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
Novel analogs of quinoline and isoindoline containing various heterocycles, such as tetrazole, triazole, pyrazole, and pyridine, were synthesized and characterized using FT-IR, NMR, and mass spectroscopy, and their antioxidant and antidiabetic activities were investigated. The previously synthesized compound was utilized in conjugation with ketone-bearing tetrazole and isoindoline-1,3-dione to synthesize Schiff's bases and . Furthermore, hydrazide was treated with aryledines to provide pyrazoles -.
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