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A superacid-promoted method for the synthesis of 9,9-diarylfluorenes is described. The chemistry involves cyclizations and arylations with biphenyl-substituted heterocyclic ketones and a mechanism is proposed involving superelectrophilic intermediates. The key reactive intermediates-dicationic and trication fluorenyl cations have been observed by low-temperature NMR and the mechanism has been further studied using DFT calculations.
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http://dx.doi.org/10.1021/acs.joc.7b00311 | DOI Listing |
J Am Chem Soc
July 2025
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States.
The recent explosion in documented chemistry from Colobognatha, a millipede subterclass with more than 240 species, has rekindled interest in the defensive secretions from these ancient animals. Prior to 2020, studies on defensive secretions by Colobognatha─the only millipedes that produce terpenoid alkaloids─were limited to a single order, Polyzoniida. However, numerous species of the order Platydesmida have recently been shown to produce structurally diverse terpenoid alkaloids with potent biological activities.
View Article and Find Full Text PDFCurr Top Med Chem
March 2025
Department of Chemistry, School of Physical Sciences, Starex University, Gurugram, Haryana, 122413, India.
Thiazole, a five-membered heterocycle containing sulfur and nitrogen, is a pivotal component in the design and synthesis of organic derivatives. Its prevalence in natural sources and its integral role in the structure of drug molecules has made it a focal point for researchers. In this study, we compiled and reviewed research from the past decade and categorized the synthesized thiazole compounds into three groups (di-substituted mono-thiazoles, tri-substituted monothiazoles, and bis-thiazoles) based on how the substituents are attached to the thiazole scaffold and additionally discussed the different techniques used by researchers to measure the antimicrobial activity of newly created compounds.
View Article and Find Full Text PDFEur J Med Chem
May 2025
School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland. Electronic address:
The Dimroth Rearrangement (DR) is an isomerization process involving the translocation of exo- and endocyclic nitrogen atoms in heterocyclic systems via a ring opening, rotation, and ring closure mechanism. Originally discovered over 120 years ago, the mechanistic occurrence of the DR on multiple heterocycles has been widely studied, and its application to the synthesis of biologically active compounds is well documented, albeit on some occasions not directly referenced. A surprisingly high number of drug discovery programs take advantage of the DR for the synthesis of heterocycle-containing compounds, including 4-aminopyrimidines and 4-anilinoquinazolines.
View Article and Find Full Text PDFMed Chem
February 2025
Institute of Pharmaceutical Research, GLA University, Mathura, Uttar Pradesh, India.
Thiazine, a six-membered heterocycle containing nitrogen and sulfur atoms, is of paramount importance due to its diverse biological functions and broad therapeutic effects. The pharmacological attributes of 1,3-thiazine span a wide range of activities, including antileukemic, antimycobacterial, anti-inflammatory, sedative, hypnotic, anti-influenza, antituberculosis, melanogenesis inhibition, BACE1 inhibition (with anti-Alzheimer's potential), growth promotion, neuroprotective, and anticonvulsant properties. Consequently, novel synthetic methodologies and the design of new 1,3-thiazine derivatives are significantly influenced by recent research findings.
View Article and Find Full Text PDFBis(indolyl)methanes (BIMs) are important heterocycle-containing molecular scaffolds that show remarkable biological and pharmacological activities. This work reports the synthesis of novel BIMs using carbohydrate-derived 5-substituted-2-furaldehydes as renewable reactants. Structural diversity was introduced in the BIMs as substituents in the indole and furaldehyde moieties.
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