New quaternary indolizidine iminosugars, with hydroxymethyl group at the ring junction, namely, C-8a-hydroxymethyl-1-deoxycastanospermine congeners 1a, 2a, 3a and their 3-oxo analogs 1b, 2b, and 3b were synthesized by using intramolecular reductive aminocyclization/lactamization of d-mannose/D-glucose derived C5-γ-azido esters as a key step wherein both the rings of the indolizidine skeleton were built up in one pot following the cascade reaction pathway. The conformations ((5)C8 or (8)C5) of 1-3 were assigned on the basis of the (1)H NMR studies. All compounds were found to be potent inhibitors of various glycosidase enzymes with Ki and IC50 values in the micromolar/nanomolar concentration range and further substantiated by molecular docking studies. The effect of synthesized iminosugars 1-3 on the cytokine secretion of IL-4, IL-6, and IFN-γ was evaluated. All compounds were found to be TH1 bias increasing the TH1/TH2 cytokines ratio (IL-6 and IL-4) indicating their potency as immunostimulating agents. Our study suggests that immunomodulatory activity of indolizidine iminosugars can be tuned by minor structural/stereochemical alterations.
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http://dx.doi.org/10.1021/acs.jmedchem.5b00951 | DOI Listing |
Fitoterapia
January 2025
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, PR China; State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, PR China. Electronic address:
Alstoscholarisine L is an architecturally complex monoterpenoid indole alkaloid with a unique ring fusion pattern, isolated from the leaves of Alstonia scholaris. The 6/5/5/6/6/6-membered rings contain two lactonic rings and one aminal carbon and possess seven contiguous aligned stereocenters, three of which are quaternary. Its structure was elucidated by extensive spectroscopic data analyses, quantum chemical computations, and single-crystal X-ray diffraction.
View Article and Find Full Text PDFChem Biodivers
June 2024
School of Chemistry and Environmental Sciences, Shangrao Normal University, 334001, Shangrao, P. R. China.
Goniomitine is of the aspidosperma alkaloid family, with an angularly fused tetracyclic skeleton housing an all-carbon quaternary carbon chiral center alongside an aminal functional group. This natural product has garnered attention as a synthetic target due to its intriguing molecular architecture and anti-proliferative activity in recent years. Following the first synthesis of (-)-goniomitine by Takano in 1991, synthetic chemists have developed various methods.
View Article and Find Full Text PDFDrug Des Devel Ther
December 2023
Department of Chemistry, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia.
Background: The present study investigates the potential bioactivity of twelve experimentally designed C-2 quaternary indolinones against spp., a bacterial group of the Enterobacteriaceae family known to cause urinary tract infections. The study aims to provide insights into the bioactive properties of the investigated compounds and their potential use in developing novel treatments against spp.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2023
Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Center, School of Pharmaceutical Sciences, Chongqing University, 55 Daxuecheng South Road, Shapingba, Chongqing 401331, China.
We report here a homo-Mannich reaction of cyclopropanol with an iminium ion, generated by an asymmetric allylic dearomatization of indole, to construct a tricyclic hydrocarbazole core, which is shared by a variety of monoterpenoid indole alkaloids across families. Through this approach, an all-carbon quaternary stereogenic center as well as an allyl and a ketone group were installed. Using this functionalized hydrocarbazole as the structural platform, D ring and E rings of different sizes (i.
View Article and Find Full Text PDFOrg Lett
June 2023
College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China.
A palladium-catalyzed ring-opening [3 + 2]-annulation of spirovinylcyclopropanyl oxindoles with seven-membered cyclic -sulfonylimines has been developed. A wide range of seven-membered benzosultams featuring both a quaternary center and axially chiral biaryl scaffolds have been afforded in an average yield of 87% with moderate to excellent diastereoselectivities. The enantioenriched benzosultams were also accessed successfully in good yields with excellent atropoenantioselectivities enabled by the Pd(dba)/(,,)-SKP ligand.
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