Die Alkaloide von Buphane Fischerei Baker

Abstract

Volumen XXXVIII, Fasciculus v (1955) 2 us a m m e n f as sung. Aus dem Kulturfiltrat von Streptomyces eurythermus n. sp. konnte ein neues lipophiles kristallines basisches Antibioticurn C5,,*lH89+2018N, das A n g o l a m y c i n , isoliert werden.Die Eigenschaften yon Angolamycin deuten auf eine Verwandtschaft mit den Antibiotica der Carbomycin-und Erythromycin-Gruppe hin.

Die Alkaloide von Crinum macrantherum ENGL. 5. Mitteilung über Amaryllidaceen‐Alkaloide

“…C 62,6 H 6,1 0 27,6 CH, CO 12,4y0 (347,4) Gcf. ,, 62,4 ,, 6,2 ,,27,7 ,,9,8 OCH,,NCH,0% Hydrolyse: 50 mg 0-Monoacetylmacranthin, in wenig Methanol gelost, wurden mit 1 ml 2 N methanol. Kalilaugc iiber Nacht bei Zimmertemperatur stehengelassen.…”

The Chemical Synthesis of the Crinine and Haemanthamine Alkaloids: Biologically Active and Enantiomerically-Related Systems that Serve as Vehicles for Showcasing New Methodologies for Molecular Assembly

“…The 8- and 9-positions of the aromatic ring are most commonly bridged by a methylenedioxy group and depending upon whether the 5,10b-ethano-bridge is α- or β-oriented, as shown in structures 1 and ent - 1 respectively, the alkaloids are described as either α- or β-crinines. Those incorporating the former framework are sometimes denoted as haemanthamine alkaloids while those embodying the enantiomerically related one are described as crinines So, for example, (+)-buphanisine [(+)- 2 ] (isolated from the widely distributed plant Sternbergia sicula ) [ 2 ] and (–)-buphanisine [(–)- 2 ] (isolated from the Central African plant Boöphane fischeri ) [ 3 ] are described as α- and β-crinines, respectively. These days it is common for compounds in either enantiomeric series to be described, collectively, as crinines [ 1 ].…”

“…Regio- and stereo-selective dihydroxylation of compound 206 gave the conduritol 207 , the hydroxyl groups of which could be selectively protected to form compound 208 . This last compound served as a substrate for a Suzuki–Miyaura cross coupling reaction with the commercially available benzo[ d ][ 1 , 3 ]dioxol-5-ylboronic acid ( 119 ), thus providing compound 209 . Reaction of the TBS ether-containing compound 209 with TBAF afforded the corresponding allylic alcohol 210 , which readily participated in an Eschenmoser–Claisen rearrangement reaction to afford amide 211 .…”

“…The first phase of this approach involved the conversion of methyl 4,6- O -benzylidene-α- d -glucopyranoside ( 216 ) ( Scheme 30 ), a material available from multiple commercial suppliers, over eight steps including a Ferrier carbocyclization, into the homo-chiral enone 217 . Addition of the Grignard reagent derived from 5-bromobenzo[ d ][ 1 , 3 ]dioxole to the carbonyl group of compound 217 and treatment of the resulting 3°-alcohol with pyridinium chlorochromate (PCC), resulting in a Dauben–Michno oxidative rearrangement, gave the β-arylated enone 218 . This intermediate was subjected to stereoselective Luche reduction, thus affording allylic alcohol 219 , which could then be engaged in a Johnson–Claisen rearrangement, thus delivering ester 220 .…”

“…Heating this major adduct resulted in electrocyclic ring-opening of the cyclopropane ring and formation of the isomeric dibromocyclohexene, the allylically-positioned halogen of which was displaced with sodium azide to give compound (±)- 264 . Staudinger reduction of this azide and reaction of the product amine with nosyl chloride (Ns-Cl) gave the sulfonamide (±)- 265 , which was engaged in a Suzuki–Miyaura cross coupling reaction with commercially available benzo[d][ 1 , 3 ]dioxol-5-ylboronic acid ( 119 ) to afford styrene (±)- 266 . N -Alkylation of this last compound with 1-bromo-2-butyne in the presence of sodium hydride then gave compound (±)- 267 that could be enaged in a palladium-catalyzed intramolecular Alder-ene (IMAE) reaction, using bis -benzylidene ethylenediamine (BBEDA) as ligand, to generate the C3a-arylated hexahydroindole (±)- 268 .…”