A highly efficient domino protocol has been developed for the synthesis of 6-aryl-4-(methylthio/amine-1-yl)-2-oxo-2-pyran-3-carbonitriles and 4-aryl-2-(amine-1-yl)-5,6,7,8-tetrahydronaphthalene-1-carbonitriles from simple and readily available α-aroylketene dithioacetals, malononitrile, secondary amines, and cyclohexanone. This elegant domino process involved consecutive addition-elimination, intramolecular cyclization, and ring opening and closing sequences. Notably, in situ generated 2-imino-4-(methylthio/amine-1-yl)-6-aryl-2-pyran-3-carbonitrile plays multiple roles in the construction of various novel polyaromatic hydrocarbons.
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http://dx.doi.org/10.1021/acsomega.7b00627 | DOI Listing |
J Org Chem
January 2025
Key Laboratory of Biomass Green Chemical Conversion of Yunnan Provincial Education Department, Yunnan Key La-boratory of Chiral Functional Substance Research and Application, School of Chemistry & Environment, Yunnan Minzu University, Kunming 650504, P. R. China.
We report a base-promoted, metal-free multicomponent tandem reaction, involving a [4 + 1 + 1] cycloaddition process between -substituted nitroarenes, aldehydes, and ammonium salts. Modifying the substituents on the nitroaromatic compounds effectively provides structurally diverse 2-substituted and 4-alkenylquinazolines with good to excellent yields (77%-90% and quinazoline 51 examples) and high tolerance for various inorganic ammonium salts (13 examples, such as NH·HO, NHCl, and NHHF). A new method for constructing 2,4-substituted quinazoline compounds with high selectivity from simple nitrogen source compounds was developed, and the reaction can be scaled up to a gram scale.
View Article and Find Full Text PDFChemistry
November 2024
Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
We report the development of an azanide (NH) surrogate which enables the facile conversion of electron-deficient (hetero)aryl halides into primary N-aryl amines under transition-metal-free conditions. The designed amidine reagent is easy to prepare, bench stable, and undergoes facile N-arylation under basic conditions at 40 °C. Intermediate N-aryl amidines are readily cleaved to form N-aryl amines in situ through hydrolysis or base-promoted elimination.
View Article and Find Full Text PDFOrg Biomol Chem
November 2024
Strait Institute of Flexible Electronics (SIFE, Future Technologies), Fujian Key Laboratory of Flexible Electronics, Fujian Normal University and Strait Laboratory of Flexible Electronics (SLoFE), Fuzhou 350117, China.
Herein, an efficient, base catalyzed cascade vinylogous Michael/Michael cycloaddition reaction of α-alkylidene succinimides and oxindole-derived pyrazolones has been successfully developed. A variety of highly functionalized cyclopentanes fused with spirooxindoles were obtained in good yields, with excellent diastereoselectivities and exclusive vinylogous site-selectivities. This strategy represents the first example of α-alkylidene succinimides serving as nucleophilic reagents to trigger a vinylogous cascade reaction.
View Article and Find Full Text PDFOrg Lett
October 2024
Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.
Herein, we evolve a base-promoted synthesis of 2-chromen-2-one and chromeno[2,3-]pyrrole scaffolds via (4 + 2) annulation of α-alkylidene succinimides with 2-hydroxyphenyl-substituted -quinone methides (-QMs). Extremely selective and switchable cyclizations were obtained by modifying the base. This metal-free protocol is highlighted by its mild reaction conditions and broad substrate scope, and the viability of the existing protocol was additionally illustrated by gram-scale synthesis and further modification.
View Article and Find Full Text PDFBioorg Chem
October 2024
Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital of Henan University, Henan University, Kaifeng 475000, China. Electronic address:
The approach of metabolic chemical reporters (MCRs) for labeling proteins has been widely used in the past several decades. Nevertheless, artificial side reaction generated with fully protected MCRs, termed S-glyco-modification, occurs with cysteine residues through base-promoted β-elimination and Michael addition, leading to false positives in the proteomic identification. Therefore, next generation of MCRs, including partially protected strategy and modifications on the backbone of monosaccharides, have emerged to improve the labeling efficiency.
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