- Biomimetic Total Syntheses of Ergot Alkaloids via Decarboxylative Giese Coupling
-
Biomimetic total syntheses of Festuclavine and Pyroclavine were achieved by a sequential radical coupling. The key steps include intramolecular decarboxylative Giese reaction to form the central C ring and 4-nitrobenzenesulfonyl (Ns)-directed indole C4-H olefination to introduce the indole C4 component. In addition, D-ring formation was completed by decarboxylative alkenylation and intramolecular SN2 reaction.
- Ge, Yuhua,Wang, Hang,Wang, Hua-Nan,Yu, Shu-Sheng,Yang, Rui,Chen, Xingyue,Zhao, Qin,Chen, Gang
-
p. 370 - 375
(2021/01/13)
-
- Asymmetric synthesis method for ergot alkaloids
-
The invention discloses an asymmetric synthesis method for ergot alkaloids, which belongs to the technical field of chemical synthesis. According to the method, after a cheap and easily available compound 1 and compound 2 are subjected to alkylation, a cy
- -
-
Paragraph 0060; 0103; 0104
(2019/02/10)
-
- Biomimetic Total Syntheses of Clavine Alkaloids
-
Biomimetic total syntheses of either enantiomers of a number of ergot alkaloids, chanoclavine I (1b), chanoclavine I aldehyde (1c), pyroclavine (1e), festuclavine (1f), pibocin A (1g), 9-deacetoxyfumigaclavine C (1h), and fumigaclavine G (1i), have been achieved from seco-agroclavine (1a). The advanced intermediate for seco-agroclavine (1a) was synthesized via a key thiourea-catalyzed intramolecular nitronate addition onto α,β-unsaturated ester.
- Chaudhuri, Saikat,Bhunia, Subhajit,Roy, Avishek,Das, Mrinal K.,Bisai, Alakesh
-
p. 288 - 291
(2018/01/17)
-
- Total Syntheses of Festuclavine, Pyroclavine, Costaclavine, epi-Costaclavine, Pibocin A, 9-Deacetoxyfumigaclavine C, Fumigaclavine G, and Dihydrosetoclavine
-
A new approach for the divergent total synthesis of eight ergot alkaloids is reported. The approach allows the first total syntheses of pyroclavine, pibocin A, 9-deacetoxyfumigaclavine C, and fumigaclavine G and also enables the efficient synthesis of festuclavine, costaclavine, epi-costaclavine, and dihydrosetoclavine. The main feature of the synthesis is the use of an unprecedented Pd-catalyzed intramolecular Larock indole annulation/Tsuji-Trost allylation cascade to assemble the tetracyclic core in one step.
- Liu, Haichao,Zhang, Xiwu,Shan, Dong,Pitchakuntla, Mallesham,Ma, Yongfan,Jia, Yanxing
-
p. 3323 - 3326
(2017/06/23)
-
- Total Syntheses of Pyroclavine, Festuclavine, Lysergol, and Isolysergol via a Catalytic Asymmetric Nitro-Michael Reaction
-
A catalytic enantioselective construction of vicinal stereocenters is reported. The reaction takes advantage of thiourea-catalyzed intramolecular nitronate addition onto α,β-unsaturated ester to afford exceptional levels of enantioselectivity (up to 97 % ee) with moderate diastereoselectivity (up to 4:1). Using this method, a cross-conjugated ester was synthesized in few steps, from which a 6-endo-trig cyclisation led to the formation of all required functionalities for total syntheses of ergot alkaloids. The strategy not only offers first total syntheses of ergot alkaloids, festuclavine (1 c), and pyroclavine (1 e), and but also an efficient and general approach to other congeners such as, lysergol (1 b), and isolysergol (1 d).
- Bhunia, Subhajit,Chaudhuri, Saikat,Bisai, Alakesh
-
supporting information
p. 11234 - 11238
(2017/08/26)
-
- Using the Pummerer cyclization-deprotonation-cycloaddition cascade of imidosulfoxides for alkaloid synthesis
-
The Pummerer reaction of imidosulfoxides bearing tethered alkenyl groups has been employed for the synthesis of several alkaloids. The required imidosulfoxides necessary for the cascade sequence were easily obtained by heating the appropriate amide with (ethylsulfenyl)acetyl chloride followed by sodium periodate oxidation. The initially formed thionium ion, obtained by treating the imidosulfoxide with acetic anhydride and p-toluenesulfonic acid, reacts with the neighboring imido group, and the resulting oxonium ion undergoes subsequent deprotenation to produce an isomunchnone dipole. This mesoionic betaine intermediate undergoes ready intramolecular dipolar cycloaddition across the neighboring π-bond. Exposure of the resulting cycloadducts to additional acetic anhydride leads to ring opening and formation of a 5-acetoxy-substituted 2(1H)-pyridone. This six-ring heterocyclic system constitutes a valuable building block for the synthesis of a variety of pyridine, quinolizidine, and clavine alkaloids. The cyclization-deprotonation-cycloaddition cascade has been successfully applied to the synthesis of the naturally occurring alkaloids onychnine, dielsiquinone, (±)-lupinine, (±)-anagyrine, (±)-pumiliotoxin C, and (±)- costaclavine.
- Padwa, Albert,Heidelbaugh, Todd M.,Kuethe, Jeffrey T.
-
p. 2368 - 2378
(2007/10/03)
-
- Total synthesis of optically active costaclavine (synthetic studies of indoles and related compounds part 48.)
-
The first total synthesis of optically active costaclavine (18), an ergot alkaloid, was accomplished starting from methyl [4R-(Z)]-[4-[[(1,1- dimethylethoxy)carbonyl]methylamino]-3,4-dihydro-1-[(4- methylphenyl)sulfonyl]benz[cd]indol-5(1H)-ylidene]acetate
- Osanai, Kumi,Yokoyama, Yuusaku,Kondo, Kazuhiro,Murakami, Yasuoki
-
p. 1587 - 1590
(2007/10/03)
-
- Synthesis and Dopamine Antagonist Activity of 2-Thioether Derivatives of the Ergoline Ring System
-
A series of 2-thioether derivatives of a number of clavine alkaloid (ergoline) ring systems have been synthesized and tested for dopamine antagonist activity.Of the compounds tested 2-(methylthio)agroclavine (8,9-didehydro-6,8-dimethyl-2-(methylthio)ergoline) (6) was the most potent and had a profile of activity in animal models indicative of potential antipsychotic activity.The synthesis and biological activity of a number of metabolites of 6, including the 13-hydroxy derivative, are also reported.
- Tupper, David E.,Pullar, Ian A.,Clemens, James A.,Fairhurst, John,Risius, Francesca C.,et al.
-
p. 912 - 918
(2007/10/02)
-
- TOTAL SYNTHESES OF CLAVINE ALKALOIDS BY AN INTRAMOLECULAR NITRONE-OLEFIN CYCLOADDITION REACTION
-
The racemic ergot alkaloids chanoclavine I (1) and 6,7-secoagroclavine (4) have been synthesized stereoselectively from indole-4-carboxaldehyde (7) in overall yields of 14 and 13 percent, respectively.Further syntheses of isochanoclavine I (2), paliclavine (5) and costaclavine (6), via the same isoxazolidine 18 are described.The key step 16-->18 (Scheme 4) involves a transient nitrone 17 which undergoes a kinetically controlled, regio- and stereoselective intramolecular cycloaddition to a 1,2-disubstituted olefinic bond.
- Oppolzer, W.,Grayson, J. I.,Wegmann, H.,Urrea, M.
-
p. 3695 - 3706
(2007/10/02)
-
- Photocyclisation of Enamides. Part 16. A New Synthesis of Clavines. The Stereostructure of Costaclavine
-
Epimeric 6,8-dimethylergolines (VI), (VII), and (IX) have been synthesised from the lactam (IVa) which was prepared by the reaction of the enamine (II) with methacryloyl chloride or methacrylamide.The stereochemistry of costaclavine (VI) has been establis
- Ninomiya, Ichiya,Kiguchi, Toshiko,Naito, Takeaki
-
p. 208 - 211
(2007/10/02)
-