The asymmetric Friedel-Crafts alkylation reaction of indoles with α,β-unsaturated ketones catalyzed by chiral phosphoric acid is reported. A wide range of indoles and 4,7-dihydroindoles were allowed to react with α,β-unsaturated ketones to give the corresponding 1,4-adducts in good to high chemical yields and with excellent enantioselectivities.
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http://dx.doi.org/10.1039/c0ob00197j | DOI Listing |
Nat Commun
December 2024
Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Marine cyclopianes are a family of diterpenoid with novel carbon skeleton and diverse biological activities. Herein, we report our synthetic and chemical proteomics studies of cyclopiane diterpenes which culminate in the asymmetric total synthesis of conidiogenones C, K and 12β-hydroxy conidiogenone C, and identification of Immunity-related GTPase family M protein 1 (IRGM1) as a cellular target. Our asymmetric synthesis commences from Wieland-Miescher ketone and features a sequential intramolecular Pauson-Khand reaction and gold-catalyzed Nazarov cyclization to rapidly construct the 6-5-5-5 tetracyclic skeleton.
View Article and Find Full Text PDFFront Plant Sci
December 2024
Key Laboratory in Flavor and Fragrance Basic Research, Zhengzhou Tobacco Research Institute, China National Tobacco Corporation, Zhengzhou, China.
Cigar tobacco leaves exhibited distinct regional characteristics, and aroma compounds were the key substances determining the different style features of cigars. However, the differences in aroma characteristics and the mechanisms of key aroma compound synthesis have not been fully elucidated. This study collected filler tobacco leaves (FTLs) from 5 representative domestic and international production regions.
View Article and Find Full Text PDFIndian J Orthop
January 2025
Department of Orthopaedic Surgery, Hillel Yaffe M.C., 3100 Hadera, Israel.
Objective: To present the clinical result of spinal fixation system made entirely of Carbon-Fiber-Reinforced (CFR)-Hybrid Polyaryl-Ether-Ether-Ketone (PEEK).
Summary Of Background Data: Fusion surgery has been used to treat chronic low back pain caused by degenerative disk disease (DDD). The traditional pedicle screw system made of titanium, though biocompatible, can lead to complications, such as stress shielding and implant failure.
Cureus
November 2024
Department of Removable Prosthodontics, Syrian Arab Republic Damascus University Faculty of Dental Medicine, Damascus, SYR.
Background: Determining the distal cantilever length in All-on-Four (All-on-4) implant-supported prostheses is a major factor in the long-term success of these prostheses. The difference in mechanical properties of materials used in the fabrication of these prostheses, such as polyether ether ketone (PEEK), may have an impact on the determination of the cantilever length that best distributes stress.
Aim: To study the distribution of stress in All-on-4 mandibular prostheses in the bone, implants, and framework according to difference cantilever length in PEEK prosthetic framework using three-dimensional finite element analysis.
AACE Clin Case Rep
September 2024
Department of Medicine, Suburban Hospital, Johns Hopkins Medicine, Bethesda, Maryland.
Background/objective: Calcium channel blockers, when taken in overdose quantities, can cause hyperglycemia requiring so-called hyperinsulinemic-euglycemic therapy. The objective of this report was to describe a patient with calcium channel blocker toxicity resulting from overdose of amlodipine.
Case Report: A 74-year-old man presented with a fall and loss of consciousness.
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