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The conformational analysis of macrocycles is a complex and challenging problem. There are many factors that contribute to this complexity. These include a large number of degrees of freedom, transannular interactions such as hydrogen bonds and hydrophobic interactions, and a range of steric interactions, along with ring strain effects. To a greater extent than within acyclic molecules, these interactions within macrocycles are coupled such that changing one dihedral angle can significantly affect other dihedral angles, further complicating the situation. However, this coupling of bond rotations and transannular interactions enables the transmission of three-dimensional information from one side of a macrocycle to the other. Making relatively small structural modifications to a macrocycle can result in local conformational changes that propagate along the ring to affect distal structural features. The factors that control how such changes can propagate are poorly understood, and it is difficult to predict which modifications will result in significant conformational reorganizations of remote regions of a macrocycle. This review discusses examples where small structural modifications to macrocyclic scaffolds change the conformational preferences of structurally remote regions of the ring. We will highlight evidence provided for conformational changes triggered by remote substituents and explanations of how these changes might occur in an effort to further understand the factors that control such phenomena.
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http://dx.doi.org/10.1021/acs.chemrev.8b00742 | DOI Listing |
Adv Mater
July 2025
Institute of Molecular Aggregation Science, Tianjin University, Tianjin, 300072, China.
Precise control over the release of light energy, distinct from conventional thermal energy management, poses significant challenges in luminescent technologies. This study pioneers organic above-room-temperature thermoluminescent materials using radical pairs as energy storage centers (ESCs), enabling controlled light energy release from multi-hour afterglows to microsecond-scale explosive bursts, accelerating the energy release rate by up to 1.8 × 10 times.
View Article and Find Full Text PDFOrg Lett
July 2025
Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, P.R. China.
A three-component construction of eight-membered nitrogen-containing heterocycles via palladium-catalyzed imidoylative cyclization of 2-isocyano--(propa-1,2-dien-1-yl)benzamides with aryl halides and carbon nucleophiles has been developed. Sequential isocyanide and allene insertion reactions facilitated the formation of medium-sized rings, overcoming the unfavorable transannular interactions and entropic factors, followed by an allylic substitution to yield benzodiazocine derivatives under mild reaction conditions. When the nucleophile was linked with aryl iodide, challenging diazocine-fused macrocycles could be accessed through an intramolecular allylic substitution process.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
May 2025
Department of Cardiology, Division of Experimental Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Pulmonary regurgitation is a common consequence following the repair of tetralogy of Fallot and can lead to heart failure. Early detection of right ventricular dysfunction remains challenging, and current clinical markers have limited predictive value to identify which patients are at risk for heart failure and require interventions. This study aimed to investigate the potential of ventriculo-arterial coupling as a marker of early right ventricular dysfunction in a porcine model of chronic pulmonary regurgitation following transannular patch repair of neonatal pulmonary stenosis.
View Article and Find Full Text PDFMolecules
December 2024
Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, School of Pharmaceutical Sciences, Taizhou University, Taizhou 318000, China.
A comprehensive phytochemical investigation of the twigs/leaves and flower buds of , a rare deciduous shrub native to China, led to the isolation of 39 structurally diverse compounds. These compounds include 11 iridoid glycosides (- and -), 20 triterpenoids (, , and -), and 8 phenylpropanoids (-). Among these, amabiliosides A () and B () represent previously undescribed bis-iridoid glycosides, while amabiliosides C () and D () feature a unique bis-iridoid-monoterpenoid indole alkaloid scaffold with a tetrahydro--carboline-5-carboxylic acid moiety.
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
August 2024
Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, km 14.5 Carretera Toluca-Atlacomulco, Toluca, C.P. 50200, México.