The superacid-promoted reactions of vinyl-substituted N-heterocycles have been studied. Diprotonated pyrimidines, quinoxalines, and quinazolines exhibit an unusual regioelectronic effect that controls the type of addition reaction observed. Depending on the ring position of the vinyl substituent, either conjugate addition or Markovnikov addition occurs. The mode of addition has been shown to correlate well to NBO calculated charges.
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http://dx.doi.org/10.1021/ja202557z | DOI Listing |
Int J Mol Sci
November 2024
Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, UK.
Different supramolecular motifs are formed by the crystallisation of amino-substituted derivatives of quinoxaline, pyrimidine and pyridazine. These were made from the corresponding mono- or dichlorinated heterocycles by a nucleophilic displacement reaction. The pyridine-type nitrogen atoms activate the chlorine atoms because they can stabilise a negative charge, which forms when the amine attacks the ring.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Chemistry, Osmania University, Hyderabad-500 007, India.
A metal- and solvent-free, one-pot and TFA-promoted method for the construction of hetero/aryl-substituted quinoxalin-2-ones, pyrazin-2(1)-ones, and pyrimidin-4(3)-ones is reported. This method involves the reaction of chloro-derivatives of nitrogen heterocycles with electron-rich arenes/heteroarenes, followed by hydroxylation. This protocol is easy to use, providing access to (hetero)aryl-substituted -heterocycles in good yields.
View Article and Find Full Text PDFPLoS One
November 2024
Department of Medical Genetics, School of Basic Medicine, Jilin Medical University, Jilin, Jilin Province, P.R. China.
Background: Alzheimer's disease (AD) is a common elderly disorder characterized by cognitive decline. Endoplasmic reticulum (ER) stress has been implicated in various neurodegenerative diseases, including AD. Stem cell factor (SCF) performs its biological functions by binding to and activating receptor tyrosine kinase c-Kit.
View Article and Find Full Text PDFEur J Med Res
October 2024
Department of Neurology, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), No.54 Youdian Road, Hangzhou, 310006, Zhejiang Province, China.
J Pak Med Assoc
October 2024
Department of Gastroenterology, Private Clinic, Karachi, Pakistan.
Primary non-response to the currently available direct acting anti-viral (DAAs) in chronic hepatitis C virus (HCV) is rare and expected in approximately only 3-4% of the patients. Among the plausible explanations, HCV resistant variant may be one of the causes among the several other viral and host factors implicated in cases who do not achieve cure. Ever since the approval of licensed DAAs in 2014, focus has been mainly on high cure rates.
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