- A combined pathway for the synthesis of nitidine family alkaloids
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Three related alkaloids, oxynitidine, nitidine and 5,6-dihydronitidine, have been afforded by the new synthetic protocols. In this approach, the Ni-catalyzed annulation reaction is indicated as the key step to construct the isoquinolinone core structure. The subsequent transformations lead to the target alkaloids.
- Pallikonda, Gangaram,Hsieh, Chang-Yu,Su, Haw-Lih,Hsieh, Jen-Chieh
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p. 5399 - 5407
(2019/11/03)
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- Preparation method of nitidine chloride
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The invention discloses a preparation method of nitidine chloride. The method comprises the following steps of 1) catalyzing 4,5-dimethoxy-2-(methoxycarbonyl) phenylboronic acid to react with azobenzene bornene to obtain an intermediate 1 by using a metal palladium/ligand; 2) dissolving the intermediate 1 with an organic solvent, then adding trifluoroacetic acid, and conducting a room temperaturereaction to obtain an intermediate 2; 3) methylating the intermediate 2, oxidizing, reducing, and treating with hydrochloric acid to obtain the nitidine chloride. The synthetic route of the method issimpler, and the total synthesis yield of the nitidine chloride is as high as 72% or more.
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Paragraph 0016; 0019; 0021
(2019/07/10)
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- Oxidative C?H/C?H Cross-Coupling Reactions between N-Acylanilines and Benzamides Enabled by a Cp*-Free RhCl3/TFA Catalytic System
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By making use of a dual-chelation-assisted strategy, a completely regiocontrolled oxidative C?H/C?H cross-coupling reaction between an N-acylaniline and a benzamide has been accomplished for the first time. This process constitutes a step-economic and highly efficient pathway to 2-amino-2′-carboxybiaryl scaffolds from readily available substrates. A Cp*-free RhCl3/TFA catalytic system was developed to replace the [Cp*RhCl2]2/AgSbF6 system generally used in oxidative C?H/C?H cross-coupling reactions between two (hetero)arenes (Cp=pentamethylcyclopentadienyl, TFA=trifluoroacetic acid). The RhCl3/TFA system avoids the use of the expensive Cp* ligand and AgSbF6. As an illustrative example, the procedure developed herein greatly streamlines the total synthesis of the naturally occurring benzo[c]phenanthridine alkaloid oxynitidine, which was accomplished in excellent overall yield.
- Shi, Yang,Zhang, Luoqiang,Lan, Jingbo,Zhang, Min,Zhou, Fulin,Wei, Wenlong,You, Jingsong
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p. 9108 - 9112
(2018/07/25)
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- Preparation of amino-substituted indenes and 1,4-dihydronaphthalenes using a one-pot multireaction approach: Total synthesis of oxybenzo[c]phenanthridine alkaloids
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Allylic trichloroacetimidates bearing a 2-vinyl or 2-allylaryl group have been designed as substrates for a one-pot, two-step multi-bond-forming process leading to the general preparation of aminoindenes and amino-substituted 1,4-dihydronaphthalenes. The synthetic utility of the privileged structures formed from this one-pot process was demonstrated with the total synthesis of four oxybenzo[c]phenanthridine alkaloids, oxychelerythrine, oxysanguinarine, oxynitidine, and oxyavicine. An intramolecular biaryl Heck coupling reaction, catalyzed using the Hermann-Beller palladacycle was used to effect the key step during the synthesis of the natural products.
- Calder, Ewen D. D.,McGonagle, Fiona I.,Harkiss, Alexander H.,McGonagle, Grant A.,Sutherland, Andrew
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p. 7633 - 7648
(2014/09/17)
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- Palladium-catalyzed tandem reaction to construct benzo[c]phenanthridine: Application to the total synthesis of benzo[c]phenanthridine alkaloids
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A concise and efficient synthesis of benzo[c]phenanthridines was accomplished by the palladium-catalyzed ring-opening coupling of azabicyclic alkene with o-iodobenzoates, followed by tandem cyclization. The strategy was successfully applied in the total synthesis of benzo[c]phenanthridine alkaloids such as sanguinarine, chelerythrine, nitidine and avicine.
- Lv, Pei,Huang, Kanglun,Xie, Longguan,Xu, Xiaohua
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p. 3133 - 3135
(2011/05/15)
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- Protecting-group-free total synthesis of isoquinoline alkaloids by nickel-catalyzed annulation of o-halobenzaldimine with an alkyne as the key step
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An efficient short total synthesis of benzo[c]phenanthridine alkaloids including oxyavicine, oxynitidine, and oxysanguinarine is described. Thus, N-methyl-o-bromobenzaldimines 1 b-d undergo regioselective cyclization with 4-(benzo[d][1,3]dioxol-5-yl)but-3-yn-1-ol (2b) in the presence of [Ni(cod) 2] (cod = 1,5-cyclooctadiene). In situ oxidation of the resultant isoquinolinium salts gives isoquinolinone derivatives 5b-d with benzo[d][1,3]dioxol-5-yl substitution at the C3 atom and a (CH 2)2OH group at the C4 atom. Later, oxidation of the alcohol group in 5b-d to the aldehyde moiety followed by acid-catalyzed cyclization and dehydration completes the total syntheses to give oxyavicine, oxynitidine, and oxysanguinarine in 67, 65, and 60% yields, respectively. The synthesis requires four steps from o-bromobenzaldehyde derivatives. Transformations of these alkaloids to the other alkaloids in this family are also discussed herein.
- Korivi, Rajendra Prasad,Cheng, Chien-Hong
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supporting information; experimental part
p. 282 - 287
(2010/04/02)
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- Total synthesis of oxyfagaronine, phenolic benzo[c]phenanthridine and general synthetic way of 2,3,7,8- and 2,3,8,9-tetrasubstituted benzo[c]phenanthridine alkaloids
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Benzo[c]phenanthridine alkaloids such as oxynitidine, oxysanguinarine, oxyavicine and phenolic oxyfagaronine were synthesized from easily available starting benzonitriles 5 and toluamides 6 using a lithiated toluamidebenzonitrile cycloaddition reaction. T
- Le, Thanh Nguyen,Cho, Won-Jea
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p. 476 - 480
(2007/10/03)
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- A Versatile Total Synthesis of Benzo[c]phenanthridine and Protoberberine Alkaloids Using Lithiated Toluamide-Benzonitrile Cycloaddition
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A new versatile synthesis of benzo[c]phenanthridine and protoberberine alkaloids using lithiated toluamide-benzonitrile cycloaddition was carried out. The coupling reaction between benzonitrile 6 with o-toluamides (8a-c) afforded 3-arylisoquinolines (9a-c
- Le, Thanh Nguyen,Gang, Seong Gyoung,Cho, Won-Jea
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p. 2768 - 2772
(2007/10/03)
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- A facile synthesis of benzo[c]phenanthridine alkaloids: Oxynitidine and oxysanguinarine using lithiated toluamide-benzonitrile cycloaddition
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Benzo[c]phenanthridine alkaloids oxynitidine and oxysanguinarine were synthesized from easily available starting benzonitrile 5 and toluamide 6 using toluamide-benzonitrile cycloaddition reaction in six steps. This method is so highly efficient that it could be a more useful way for preparing fully aromatized benzo[c]phenanthridine compounds.
- Le, Thanh Nguyen,Gang, Seong Gyoung,Cho, Won-Jea
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p. 2763 - 2766
(2007/10/03)
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- Synthesis of benzo[c]phenanthridine alkaloids, using a novel palladium-phosphine combination system - Pd(OAc)2, DPPP, and Bu3P
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Total synthesis of several benzo[c]phenanthridine alkaloids was accomplished via an aryl-aryl coupling reaction using a novel Pd reagent prepared from Pd(OAc)2 DPPP, and Bu3P. This is a versatile method for the coupling reactions of not only aryl triflates and arenes but also aryl halides and arenes.
- Harayama, Takashi,Akiyama, Toshihiko,Nakano, Yuichiro,Shibaike, Kentaro,Akamatsu, Hisashi,Hori, Akihiro,Abe, Hitoshi,Takeuchi, Yasuo
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p. 237 - 241
(2007/10/03)
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- Aryl-aryl coupling reaction catalyzed by a palladium reagent prepared from Pd(OAc)2 and n-Bu3P
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A palladium reagent prepared from Pd (OAc)2 (0.2 eq) and n-Bu3P (0.6 eq) catalyzed an aryl-aryl coupling reaction. This procedure is effective for coupling reactions of aryl triflate possessing no oxygen groups with arene, and of aryl iodide with arene.
- Harayama, Takashi,Hori, Akihiro,Nakano, Yuichiro,Akiyama, Toshihiko,Abe, Hitoshi,Takeuchi, Yasuo
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p. 159 - 164
(2007/10/03)
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- Synthesis of benzo[c]phenanthridine alkaloids, chelerythrine and nitidine, using a novel palladium-phosphine combination system -Pd(OAc)2, DPPP, and Bu3P-
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Total synthesis of chelerythrine (1) and nitidine (4) was accomplished via the aryl-aryl cyclization reaction using a novel Pd reagent prepared from Pd(OAc)2, DPPP, and Bu3P. The present method was very versatile for coupling reaction not only between aromatic inflate and arene but also between aromatic halide and arene.
- Harayama, Takashi,Akiyama, Toshihiko,Nakano, Yuichiro,Shibaike, Kentaro
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p. 1989 - 1992
(2007/10/03)
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- Concise synthesis of nitidine by palladium-assisted biaryl coupling reaction
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Formal total synthesis of nitidine (1) was accomplished via oxynitidine (7) by the internal aryl-aryl coupling reaction of iodo-amide (6) using palladium-assisted cyclization reaction.
- Harayama, Takashi,Shibaike, Kentaro
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p. 191 - 195
(2007/10/03)
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- A New Approach to the Synthesis of Antitumor Benzophenanthridine Alkaloids. Formal Synthesis of Nitidine
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The synthesis of benzophenanthridine alkaloids by an efficient new convergent strategy on the Diels-Alder reaction between an α-pyrone and an aryne is described.With minor modifications, norbenzophenanthridines and phenanthridines and their 12-amino deriv
- Perez, Dolores,Guitian, Enrique,Castedo, Luis
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p. 5911 - 5917
(2007/10/02)
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- TRANSFORMATION OF PROTOBERBERINES INTO BENZOPHENANTHRIDINES A NOVEL AND EFFICIENT SYNTHESIS OF ANTITUMOR BENZOPHENANTHRIDINE ALKALOIDS, FAGARONINE AND NITIDINE
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Antileukemic benzophenanthridine alkaloids, fagaronine (1a) and nitidine (1c) were synthesized from the corresponding protoberberines through C6-N bond fission and subsequent cyclization between C6 and C13 position of the protoberberines.
- Hanaoka, Miyoji,Yamagishi, Hiroshi,Marutani, Mari,Mukai, Chisato
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p. 5169 - 5172
(2007/10/02)
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