Search results for "Total synthesis"

Stereoselective Synthesis of Enantiomerically Pure Nupharamine Alkaloids from Castoreum

2009

An animalic note: The first total synthesis of the all-cis nupharamine 2, an alkaloid from beaver castoreum, is based on the stereoselective domino Mannich-Michael reaction of N-galactosylfurylaldimine to give 1 (Piv = pivaloyl), subsequent conjugate cuprate addition, and stereoselective protonation of the enolate. These reactions are all controlled by the carbohydrate. Protonation of the enolate after cleavage of the auxiliary leads to epimer 3.

ChemInform Abstract: Inhibitors of Inducible NO Synthase Expression: Total Synthesis of (S)-Curvularin (Ia) and Its Ring Homologues.

2008

Rational design of a fluopyram hapten and preparation of bioconjugates and antibodies for immunoanalysis

2015

A fluopyram hapten was designed in which insignificant electronic and structural modifications were foreseen and all potentially interacting chemical moieties were maintained. This hapten was prepared by total synthesis and three immunologically active bioconjugates were obtained and characterized. High-affinity and specific antibodies to fluopyram were raised.

Stereoselective Total Synthesis and Absolute Configuration of the Natural Decanolides (−)-Microcarpalide and (+)-Lethaloxin. Identity of (+)-Lethalox…

2005

[reaction: see text] Convergent, stereoselective syntheses of the pharmacologically active, naturally occurring lactones (-)-microcarpalide and (+)-lethaloxin have been achieved from the commercially available, chiral reagents (R)-glycidol, (S,S)-tartaric acid, and d-ribose as the starting materials. These syntheses have further served to establish the hitherto unknown absolute configuration of (+)-lethaloxin and to show its identity with (+)-pinolidoxin.

Total synthesis of two potent anti-inflammatory macrolactones of the oxacyclododecindione type

2015

An esterification/Friedel-Crafts-cyclization approach permitted the first successful synthetic entry into the oxacyclododecindione subclass of the dihydroxyphenylacetic acid lactone-type natural products. This route allowed the preparation of two highly active anti-inflammatory fungal secondary metabolites 14-deoxyoxacyclododecindione and 14-deoxy-4-dechlorooxacyclododecindione as well as their 14-desmethyl analogues.

Total synthesis and biological evaluation of seven new anti-inflammatory oxacyclododecindione-type macrolactones

2020

Through variation of our previously published total synthesis of two highly active anti-inflammatory macrolactones from the oxacyclododecindione family (J. Tauber, M. Rohr, T. Walter, G. Erkel and T. Opatz, Org. Biomol. Chem., 2015, 13, 7813-7821), seven new representatives of this compound class were prepared. Substitution of the 14-hydroxy group in oxacyclododecindione with a methyl substituent provided a readily accessible non-natural analogue which has similar pharmacological properties to the scarcely available natural product. Since the producible amount of substance is therefore no longer restricted by low fermentation yields, extensive in vivo studies become possible for the first t…

Synthesis of the phytohormone [11C]methyl jasmonate via methylation on a C18 Sep Pak? cartridge

2005

[11C]labeled (±)-methyl jasmonate was synthesized using a C18 Sep Pak™ at ∼100°C to sustain a solid-supported 11C-methylation reaction of sodium (±)-jasmonate using [11C]methyl iodide. After reaction, the Sep Pak was rinsed with acetone to elute the labeled product, and the solvent evaporated rendering [11C]-(±)-methyl jasmonate at 96% radiochemical purity. The substrate, (±)-jasmonic acid, was retained on the Sep Pak so further chromatography was unnecessary. Total synthesis time was 25 min from the end of bombardment (EOB) which included 15 min to generate [11C]methyl iodide using the GE Medical Systems PET Trace MeI system, 5 min for reaction and extraction from the cartridge, and 5 min …

Automated synthesis and purification of [18F]fluoro-[di-deutero]methyl tosylate

2013

Automated synthetic procedures of [ 18 F]fluoro-[di-deutero]methyl tosylate on a GE TRACERlab FX F-N module and a non-commercial synthesis module have been developed. The syntheses included azeotropic drying of the [ 18 F]fluoride, nucleophilic 18 F-fluorination of bis(tosyloxy)-[di-deutero]methane, HPLC purification and subsequent formulation of the synthesized [ 18 F]fluoro-[di-deutero]methyl tosylate (d2-[ 18 F]FMT) in organic solvents. Automation shortened the total synthesis time to 50min, resulting in an average radiochemical yield of about 50% and high radiochemical purity (>98%). The possible application of this procedure to commercially available synthesis modules might be of signi…

A high-yielding modular access to the lamellarins: synthesis of lamellarin G trimethyl ether, lamellarin η and dihydrolamellarin η.

2013

Inhibitors of inducible NO synthase expression: total synthesis of (S)-curvularin and its ring homologues.

2008

(S)-Curvularin and its 13-, 14-, and 16-membered lactone homologues were synthesized through a uniform strategy in which a Kochi oxidative decarboxylation and ring-closing metathesis reactions constitute the key processes. In the evaluation of the anti-inflammatory effects of the synthesized compounds in assays using cells stably transfected with a human iNOS promoter-luciferase reporter gene construct, the 14- and 16-membered homologues showed a slightly higher inhibitory effect towards iNOS promoter activity than curvularin itself. However, the larger ring homologues also exhibited higher cytotoxicity, manifest in downregulated eNOS promoter activity. In contrast, the di-O-acetyl and 4-ch…