Search results for "ALKALOIDS"

Zur C-17-Oxidation von Clavinalkaloiden mit primärer alkoholischer Hydroxylgruppe

1975

Die Oppenauer-Oxidation von 1 mit Cyclohexanon fuhrt zu dem Aldolkondensationsprodukt 4 und der Carbonsaure 3. Analog konnte Lysergsaure (8) in geringer Menge aus 6 gewonnen und im Reaktionsgemisch von 7 nachgewiesen werden. Damit wurden erstmals Clavinalkaloide mit primarer alkoholischer Hydroxylgruppe chemisch zu den entsprechenden Carbonsauren oxidiert. C-17-Oxidation of Clavine Alkaloids with a Primary Alcoholic Hydroxyl Group. 1 is converted by Oppenauer oxidation with cyclohexanone to the aldol condensation product 4 and to the carboxylic acid 3. Lysergic acid (8) was obtained in a small yield by the analogous reaction of 6 and was found in the reaction mixture of 7. Thus clavine alka…

Partialsynthese neuer Ergolinderivate aus Clavinalkoloiden, 5. Mitt. N-1- und N-6-mono- und disubstituierte Festuclavine

1985

Festuclavin (1), 6-Cyano-6-nor-1 (3), 6-Nor-1 (5) und 6-Allyl-6-nor-1 (7) lassen sich in flussigem Ammoniak mit Kalium und dem entsprechenden Iodid in ihre 1-Allyl- und 1-Propyl-Derivate uberfuhren. Die Darstellung von 7 aus 5 wird beschrieben. Partial Syntheses of New Ergoline Derivatives from Clavine Alkaloids, V: Festuclavines Mono- and Disubstituted at N-1 and N-6 Festuclavine (1), 6-cyano-6-nor-1 (3), 6-nor-1 (5) and 6-allyl-6-nor-1 (7) were converted to their 1-allyl- and 1-propyl derivatives with potassium and the corresponding iodide in ammonia. The preparation of 7 from 5 is described.

The hedgehog receptor patched is involved in cholesterol transport.

2011

International audience; BACKGROUND: Sonic hedgehog (Shh) signaling plays a crucial role in growth and patterning during embryonic development, and also in stem cell maintenance and tissue regeneration in adults. Aberrant Shh pathway activation is involved in the development of many tumors, and one of the most affected Shh signaling steps found in these tumors is the regulation of the signaling receptor Smoothened by the Shh receptor Patched. In the present work, we investigated Patched activity and the mechanism by which Patched inhibits Smoothened. METHODOLOGY/PRINCIPAL FINDINGS: Using the well-known Shh-responding cell line of mouse fibroblasts NIH 3T3, we first observed that enhancement …

Green coffee, bioactive compounds’ analysis of experimental cultivation in Sicily: a new frontier in the Sicilian food sector

2023

Recently, climate change represents a new possibility for tropical cultivars fruit in Mediterranean areas. The focus of this work is the evaluation of the real possibility of coffee cultivation in Sicily, like coffee plants grown in tropical and subtropical regions. The objective was to evaluate plant adaptation to our climate and to study the chemical qualities of green coffee pulps and seeds: total phenolic content, antiradical capacity, fatty acids, amino acids, alkaloids, vitamins, proximate composition, polyphenolic profile and other bioactive compounds of cosmetic, pharmaceutical and agrary interest. Temperature, light and vegetative growth of Coffea arabica L. cv. “Caturra” plants we…

Selective chiral inhibition of Ca2+ entry promoted by bisbenzyltetrahydroisoquinolines in rat uterus.

1992

Abstract The effects of diltiazem and six bisbenzyltetrahydroisoquinoline alkaloids (antioquine, 7-O-methylantioquine, dimethylantioquine, monterine, granjine and cordobimine) were studied in rat isolated uterus in order to clarify the mechanisms of their relaxant actions. All the compounds tested completely relaxed KCl-induced contractions and totally or partially inhibited oxytocin-induced rhythmic contractions. Only alkaloids with absolute configurations (1R,1′S or 1R,1′R) acted intracellularly, promoting relaxation of contractile responses induced by oxytocin in a Ca2+-free medium, as does papaverine. Alkaloids of the antioquine series (1S,1′R) selectively inhibited Ca2+ entry. The grea…

Synthesis and Antiproliferative Activity of 2,5-bis(3′-Indolyl)pyrroles, Analogues of the Marine Alkaloid Nortopsentin

2013

2,5-bis(3′-Indolyl)pyrroles, analogues of the marine alkaloid nortopsentin, were conveniently prepared through a three step procedure in good overall yields. Derivatives 1a and 1b exhibited concentration-dependent antitumor activity towards a panel of 42 human tumor cell lines with mean IC50 values of 1.54 μM and 0.67 μM, respectively. Investigating human tumor xenografts in an ex-vivo clonogenic assay revealed selective antitumor activity, whereas sensitive tumor models were scattered among various tumor histotypes.

New 2-Methoxy Acetylenic Acids and Pyrazole Alkaloids from the Marine Sponge Cinachyrella sp.

2017

Three new 2-methoxy acetylenic acids (1–3) and a known derivative (4), in addition to three new natural pyrazole alkaloids (5–7) were isolated from an Indonesian marine sponge of the genus Cinachyrella. Compounds 5 and 6 have previously been reported as synthetic compounds. The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopy as well as by mass spectrometric data. The absolute configuration of the new acetylenic acid derivatives (1–3) was established by ECD spectroscopy. All isolated compounds were evaluated for their cytotoxicity against L5178Y mouse lymphoma cells. Compounds 1–4 exhibited strong activity with an IC50 value of 0.3 µ…

Bioaccesibility of Cylindrospermopsin from cooked fish muscle after the application of an in vitro digestion model and its bioavailability.

2017

Humans can be exposed to cyanotoxins through the ingestion of contaminated water, food or beverages. In the present work, the bioaccesibility of Cylindrospermopsin (CYN), one of the most relevant cyanotoxins, was evaluated in a pure CYN solution and cooked CYN-contaminated fish muscles (20 μg/mL). An in vitro digestion model including the salivar, gastric, duodenal and colonic phases was performed, being each fraction analyzed by HPLC-MS-MS to evaluate CYN degradation. Moreover, Caco-2/TC7 cells were exposed to the digested duodenal and colonic phases to elucidate the final bioavailability of CYN in an approximation to the real human exposure scenario. The results revealed that CYN bioacces…

Organocatalytic approach to benzofused nitrogen-containing heterocycles: enantioselective total synthesis of (+)-angustureine.

2008

Synthetic studies on 1-azabicyclo[5.3.0]decane alkaloids

2018

The first chapter introduces the reader to the concept of natural product total synthesis and its importance to chemistry, other sciences, and society. The second chapter reviews the chemistry of natural products containing 1-azabicyclo[5.3.0]decane motifs. This bicyclic motif and the natural products related to it, have been a continuous source of synthetic inspiration over the last decades. The second chapter of the thesis reviews the strategies and tactics developed. The third chapter covers the author’s total synthesis of stemoamide, a 1-azabicyclo[5.3.0]decane motif containing alkaloid. Additionally, two diastereomers of stemoamide were synthesized, allowing their structural reassignme…