We introduce, for the first time, an inorganic base-mediated cyclization and auto-oxidation of bisallenones/bisalkynones. This reaction is realized under mild conditions through precise control of the base and atmosphere, providing a wide range of structurally diverse fused-pyran derivatives with moderate to excellent yields. Utilizing KOH as the initiator under a nitrogen atmosphere, a series of novel cyclohexane-fused pyran derivatives was obtained as the primary product. In contrast, under aerobic conditions with NaS as the catalyst, oxidative cyclization predominantly occurred, yielding cyclohexanone-fused pyran derivatives. The protocol also exhibits significant regioselectivity, particularly when asymmetric bisallenones/bisalkynones are selected as substrates.
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http://dx.doi.org/10.1039/d4ob00835a | DOI Listing |
J Org Chem
August 2024
Department of Medicinal Chemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India.
The stereo- and regioselective formation of chiral molecules is an interesting and important topic in organic synthesis due to its wide applicability and intricacy during synthesis. Herein, we disclose a method for the selective functionalization of glycal dienes for synthesizing different glycosides and branched sugars stereo- and regioselectively. The methodology is broad regarding the substrate scope in which various nucleophiles and glycals were explored.
View Article and Find Full Text PDFOrg Biomol Chem
August 2024
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100040, People's Republic of China.
We introduce, for the first time, an inorganic base-mediated cyclization and auto-oxidation of bisallenones/bisalkynones. This reaction is realized under mild conditions through precise control of the base and atmosphere, providing a wide range of structurally diverse fused-pyran derivatives with moderate to excellent yields. Utilizing KOH as the initiator under a nitrogen atmosphere, a series of novel cyclohexane-fused pyran derivatives was obtained as the primary product.
View Article and Find Full Text PDFOrg Lett
August 2024
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, School of Environment, Henan Normal University, Xinxiang, Henan 453007, China.
Presented herein is a novel synthesis of indenone-fused pyran derivatives via the cascade reactions of aryl enaminones with cyclopropenones. The formation of products involves a one-pot cascade procedure consisting of aryl C-H bond and enamine C-H bond functionalization along with C-C bond cleavage of cyclopropenone and 1,3-rearrangement of the in situ-formed allylic alcohol moiety followed by intramolecular O-nucleophilic addition and MeNH elimination. To our knowledge, this is the first synthesis of indenone-fused pyran derivatives via simultaneous formation of both indenone and pyran scaffolds through concurrent unsymmetrical relay C-H bond activation and double C-C/C-O bond formation.
View Article and Find Full Text PDFFuture Med Chem
November 2022
H. E. J. Research Institute of Chemistry, International Center for Chemical & Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.
To discover novel lead molecules against diabetes, Alzheimer's disease and oxidative stress, a library of arylated pyrazole-fused pyran derivatives, , were synthesized in a one-pot reaction. H-NMR spectroscopic and electron ionization mass spectrometry techniques were used to characterize the synthetic hybrid molecules . Analogs were screened against four indispensable therapeutic targets, including -amylase, -glucosidase, acetylcholinesterase and butyrylcholinesterase enzymes.
View Article and Find Full Text PDFActa Chim Slov
September 2022
Chemistry Department, faculty of science, Cairo university.
2-Amino-6-oxo-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (3) was prepared from the reaction of cyclohexane-1,4-dione with elemental sulfur and malononitrile in 1,4-dioxane and triethylamine as catalyst. The latter compound reacted with triethyl orthoformate and either malononitrile or ethyl cyanoacetate in 1,4-dioxane in the presence of triethylamine to produce 4H-thieno[2,3-f]chromene derivatives 10a,b. In addition, fused pyran and pyridine derivatives were synthesized starting from compound 3.
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