A5045730028- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Hedgehog Signaling Pathway Studies
- Chemical synthesis and alkaloids
- Synthetic Organic Chemistry Methods
- Chemical Synthesis and Analysis
- Microbial Natural Products and Biosynthesis
- Epigenetics and DNA Methylation
- Innovative Microfluidic and Catalytic Techniques Innovation
- Oxidative Organic Chemistry Reactions
- Marine Sponges and Natural Products
- Cyclization and Aryne Chemistry
- Steroid Chemistry and Biochemistry
- Plant biochemistry and biosynthesis
- Synthesis and Biological Activity
- Inflammatory mediators and NSAID effects
- Chemistry and Chemical Engineering
- Alkaloids: synthesis and pharmacology
- Traditional and Medicinal Uses of Annonaceae
- Crystallography and molecular interactions
- Phytochemical Studies and Bioactivities
- 3D Printing in Biomedical Research
- Nanomaterials for catalytic reactions
- Chemical Synthesis and Reactions
- Asymmetric Synthesis and Catalysis
Leibniz University Hannover
2022-2024
Max Planck Institute of Colloids and Interfaces
2023
Sun Yat-sen University
2023
Ludwig-Maximilians-Universität München
2023
Qujing Normal University
2023
Idorsia (Switzerland)
2023
Kyonggi University
2023
Minzu University of China
2023
Freie Universität Berlin
2016-2021
Rice University
2013-2016
The development of an enantioselective allylic alcohol dichlorination catalyzed by dimeric cinchona alkaloid derivatives and employing aryl iododichlorides as chlorine sources is reported. Reaction optimization, exploration the substrate scope, a model for stereoinduction are presented.
An improved sulfenylation method for the preparation of epidithio-, epitetrathio-, and bis-(methylthio)diketopiperazines from diketopiperazines has been developed. Employing NaHMDS related bases elemental sulfur or bis[bis(trimethylsilyl)amino]trisulfide (23) in THF, developed was applied to synthesis a series natural designed molecules, including epicoccin G (1), 8,8'-epi-ent-rostratin B (2), gliotoxin (3), (4), emethallicin E (5), haematocin (6). Biological screening selected synthesized...
From Homer to hedgehog: Cyclopamine, the first inhibitor of hedgehog signaling pathway, causes cyclopia in embryos but adults it is a potent anticancer drug. A concise biomimetic and diastereoselective synthesis cyclopamine (2) starting from commercially available dehydroepiandrosterone (1) now also provides access several analogues.
Triterpenoids and related abeo-steroids are of interest to the scientific community for their potent varied biological activities as well unique structures. Within this large diverse family natural products, fir metabolites (−)-spirochensilide A B particularly noteworthy controversial biogenesis. We herein report chemical synthesis spirochensilides, which involves a concerted sequence bioinspired rearrangements contributing its resolution. Points divergence after each rearrangement step also...
Abstract A catalytic asymmetric total synthesis of the potent and selective antileukemic Δ 12 ‐prostaglandin J 3 (Δ ‐PGJ ) is described. The convergent proceeded through intermediates 2 , formed enantioselectively from readily available starting materials coupled an aldol reaction followed by dehydration to afford stereoselectively cyclopentenone alkylidene structural motif molecule.
The synthesis of QRSTUVWXYZA′ domains 7, 8, and 9 the highly potent marine neurotoxin maitotoxin (1), largest secondary metabolite isolated to date, is described. devised synthetic strategy entailed a cascade Takai–Utimoto ester olefination/ring closing metathesis construct ring Y, hydroxydithioketal cyclization/methylation sequence cast X, Horner–Wadsworth–Emmons coupling WXYZA′ ketophosphonate 11 with QRSTU aldehyde 12 form enone 10, reductive hydroxyketone closure forge V. 2D NMR...
A series of Δ12-prostaglandin J3 (Δ12-PGJ3) analogues and derivatives were synthesized employing an array synthetic strategies developed specifically to render them readily available for biological investigations. The compounds evaluated their cytotoxicity against a number cancer cell lines, revealing nanomolar potencies certain lines. Four (2, 11, 21, 27) demonstrated inhibition nuclear export through covalent addition at Cys528 the receptor Crm1. One these (i.e., 11) is currently under...
Abstract The synthesis of strophasterol A, a moderator endoplasmatic reticulum (ER) stress in Alzheimer's disease, and the first member structurally unprecedented class secosterols, was achieved through implementation key step its proposed biosynthesis two C−H oxidations. Analysis innate reactivity intermediates enabled identification novel way to prepare an α‐chloro‐γ‐hydroxy‐δ‐keto enone, as well vinylogous α‐ketol rearrangement δ‐keto carboxylic acid.
A switchable radical framework reconstruction approach to structurally unique 13(14 → 8),14(8 7)diabeo-steroid swinhoeisterol was developed. The conversion of an ergostane skeleton proceeded through the intermediacy a 8)abeo-framework as present in dankasterone and periconiastone family natural products features β scission 14-alkoxy with concomitant generation C8-C13 bond. From this intermediate, dependent on conditions employed, cascade continues Dowd-Beckwith rearrangement leads formation...
No longer just analytical: Previously, (2R,3S)-isocitric acid (1), a component of the citric cycle, had not been available on preparative scale. A new route to this kilogram scale combines biotechnological formation through fermentation from sunflower oil with chemical separation process. In variety transformations into further chiral derivatives, 1 is established as valuable member pool (see scheme). Supporting information for article WWW under...
The combination of theoretical and computational studies with organic synthesis biological investigations has led to exo-cyclopamine. This stable highly potent derivative cyclopamine promises big potential as an experimental drug against several types human cancer.
A three-step sequence to access functionalized 4,5-dihydrooxepines from cyclohexenones has been developed. This approach features a regioselective Baeyer–Villiger oxidation and subsequent functionalization via the corresponding enol phosphate intermediate.
Abstract An enantioselective total synthesis of trioxacarcin DC‐45‐A2 ( 1 ) featuring a novel Lewis acid‐induced cascade rearrangement epoxyketone 6 to forge the polyoxygenated 2,7‐dioxabicyclo[2.2.1]heptane core molecule is described.
Steroids have long been sought after as synthetic targets. Their rearranged counterparts, though, only recently received more attention, when isolation and biological testing programs revealed several molecular entities that were both structurally intriguing well biologically relevant. This review will highlight contemporary approaches towards the growing class of seco- abeo-steroids some related triterpenoid natural products. 1 Introduction 2 Cyclocitrinol 2.1 Li’s Synthesis 2.2 Gui’s 3...
Abstract Withanolides are steroidal lactones from nightshade (Solanaceae) plants. Of the over 1,200 known representatives, many possess potent biological activities, but their drug potential has not been fully realised up until now. A central obstacle is limited availability of minor withanolides, caused by a lack knowledge about underlying biosynthetic pathways. Here, we combine phylogenomics with metabolic engineering to overcome this limitation. By sequencing genome medicinal plant and...
A biomimetic three-step transformation of classical "6-6-6-5"-steroids into their C-nor-D-homo-counterparts gives an easy and fast access to this highly important substructure natural products, as it is found in cyclopamine, nakiterpiosin. novel reagent combination allows for the rearrangement even 17-keto steroids with high endoselectivity. In several examples broadness strategy outlined.
Abstract The total synthesis of Δ 12 ‐prostaglandin J 3 (Δ ‐PGJ , 1 ), a reported leukemia stem cell ablator, through number strategies and tactics is described. signature cross‐conjugated dienone structural motif was forged by an aldol reaction/dehydration sequence from key building blocks enone 13 aldehyde 14 whose lone stereocenters were generated asymmetric Tsuji–Trost reaction Mukaiyama reaction, respectively. During this program, substituent‐governed regioselectivity pattern for the...
A general strategy for the synthesis of 3,4-dioxygenated quinolin-2-one natural products is reported. The key step a regioselective insertion arynes into unsymmetric imides. When performed in continuous flow, reaction proceeds within minutes, while lower yields and longer times are observed batch. resulting N-acylated 2-aminobenzophenones were transformed to (±)-peniprequinolone, (±)-aflaquinolones E F, (±)-6-deoxyaflaquinolone E, (±)-quinolinones B, (±)-aniduquinolone C 1-3 steps.