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11.
Novel organometallic chalcones functionalized with a crown ether fragment as optical ion chemosensors 下载免费PDF全文
Fernando Godoy Tamara Maldonado Erick Flores Nicolás Agurto Rodrigo González Guillermo Ferraudi Graham Lappin 《应用有机金属化学》2018,32(3)
We previously reported the synthesis and characterization of new organometallic chalcones derived from ferrocene, cyrhetrene and cymantrene functionalized with a benzo‐15‐crown‐5 fragment. The ferrocene and cyrhetrene chalcones have been investigated as chemosensors for metal ions with optical response in acetonitrile. Several metal ions were selected considering the diameter of the cavity and the charge‐to‐radius ratio of the cation. The stoichiometry of the complexes was determined using Job's method. It was found that Na+ and Ca2+ complexes have a 1:1 stoichiometry while a 2:1 (metaloligand‐to‐cation) stoichiometry was determined for Ba2+ and Pb2+ complexes. The association constants were calculated according to the stoichiometry of the complex and the results showed that they are directly affected by the electron‐withdrawing nature of the organometallic fragment. Moreover, complexes of ferrocenyl chalcone have larger association constants than those of the cyrhetrenyl analogue. This experimental observation is consistent with the electronic properties of the ferrocenyl fragment. 相似文献
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Access to the Aeruginosin Serine Protease Inhibitors through the Nucleophilic Opening of an Oxabicyclo[2.2.1]heptane: Total Synthesis of Microcin SF608 下载免费PDF全文
Stefan Diethelm Corinna S. Schindler Prof. Dr. Erick M. Carreira 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):6071-6080
Serine proteases play key roles in many biological processes and are associated with several human diseases such as thrombosis or cancer. During the search for selective inhibitors of serine proteases, a family of linear peptides named the aeruginosins was discovered in marine cyanobacteria. We herein report an entry route into the synthetically challenging core fragment of these natural products. Starting from the common oxabicyclic building block 11 , we accessed the octahydroindole core of the aeruginosins, exemplified by the total synthesis of microcin SF608 ( 2 ). Key to the synthetic strategy is a highly efficient nucleophilic opening of an oxabicyclo[2.2.1]heptane producing the hydroindole motif of microcin SF608. Moreover, during the synthetic efforts we have observed an unusual regioselective epoxide reduction. Detailed experimental studies of this reaction led us to propose a mechanistic rationale involving intramolecular hydrogen atom delivery by a carbamate NH group to control the regioselectivity of the homolytic epoxide cleavage. 相似文献
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Michael A. Schafroth Giuseppe Zuccarello Simon Krautwald Dr. David Sarlah Prof. Dr. Erick M. Carreira 《Angewandte Chemie (International ed. in English)》2014,53(50):13898-13901
All four stereoisomers of Δ9‐tetrahydrocannabinol (Δ9‐THC) were synthesized in concise fashion using stereodivergent dual catalysis. Thus, following identical synthetic sequences and applying identical reaction conditions to the same set of starting materials, selective access to the four stereoisomers of THC was achieved in five steps. 相似文献
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Santana-Martínez Ivette Ramírez-Palma María Teresa Sánchez-Escalera Javier Martínez-Otero Diego García-Eleno Marco A. Dorazco-González Alejandro Cuevas-Yañez Erick 《Structural chemistry》2020,31(1):191-201
Structural Chemistry - Structural insights of a group of bi-1,2,3-triazoles derived from oxidative CuAAC are described through an X-ray crystallography study, distinguishing a dihedral angle which... 相似文献
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[reaction: see text] An optimized process for the addition of terminal alkynes to chiral nitrones using ZnCl2 and NEt3 in toluene is reported. The new reaction protocol is facile to perform and cost-effective. The resulting optically active propargyl N-hydroxylamines are isolated in good to excellent yield and high diastereoselectivity. 相似文献