- Direct C-H Allylation of N-Acyl/Sulfonyl Tetrahydroisoquinolines and Analogues
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A highly efficient direct C-H allylation reaction at the α position of N-acyl/sulfonyl tetrahydroisoquinolines under mild conditions was developed. The reaction was also suitable for allylation of other protected nitrogen-containing heterocycles. Several
- Yan, Changcun,Liu, Yuxiu,Wang, Qingmin
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- One-pot synthesis of (±)-crispine A and its C-ring-substituted analogs
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A straightforward access to crispine A and C-ring-substituted analogs by 1,4-addition of a deprotonated α-amino nitrile to α,β- unsaturated carbonyl compounds is described. If the reduction step is omitted, substituted 5,6-dihydropyrrolo[2,1-α]isoquinolin
- Meyer, Nino,Opatz, Till
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- Total synthesis of the antitumor active pyrrolo[2,1-a]isoquinoline alkaloid (±)-crispine a
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Addition of a propargyl Grignard reagent to 3,4-dihydro-6,7- dimethoxyisoquinoline, silver(I)-promoted oxidative cyclization, and chemoselective hydrogenation of the pyrrole ring provide a simple three-step route to the antitumor active pyrrolo[2,1-a]isoquinoline alkaloid (±)-crispine A.
- Kn?lker, Hans-Joachim,Agarwal, Sameer
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- Facile two-step synthesis of crispine A and harmicine by cyclopropylimine rearrangement
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The synthesis of 4 and 8 is reported. These intermediates are obtained by a one-pot tandem cyclization of 1 and 6, respectively, via Bischler Napieralski reaction followed by cyclopropylimine rearrangement. Compounds 4 and 8 were reduced by sodium borohydride in methanol to afford cytotoxic alkaloid (±)-crispine A and antileishmania compound (±)-harmicine.
- Saha, Sanjay,Venkata Ramana Reddy, Ch.,Patro, Balaram
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- Direct Arylation of Distal and Proximal C(sp3)-H Bonds of t-Amines with Aryl Diazonium Tetrafluoroborates via Photoredox Catalysis
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A visible light-mediated arylation protocol for t-amines has been reported through the coupling of γ- and α-amino alkyl radicals with different aryl diazonium salts using Ru(bpy)3Cl2·6H2O as a photocatalyst. Structurally different 9-aryl-9,10-dihydroacridine, 1-aryl tetrahydroisoquinoline, hexahydropyrrolo[2,1-a]isoquinoline, and hexahydro-2H-pyrido[2,1-a]isoquinoline frameworks with different substitution patterns have been synthesized in good yield using this methodology.
- Mondal, Pradip Kumar,Tiwari, Sandip Kumar,Singh, Pushpendra,Pandey, Ganesh
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p. 17184 - 17196
(2021/12/02)
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- One-pot tandem route to fused indolizidines and quinolizidines: Application in the synthesis of alkaloids and bioactive compounds
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Fused indolizidines and quinolizidines are important skeletons in a variety of natural products and pharmacologically important compounds. A one-pot tandem route from amide to fused indolizidines and quinolizidines is disclosed. This method is conducted in mild conditions and shows well tolerance of functional groups. It is also easy to be scaled up to gram scale and can be applied smoothly to the total synthesis of alkaloids such as (±)-crispine A, (±)-xylopinine, (±)-desbromoarborescidine A, (±)-harmicine and other bioactive substances.
- Song, Qiao,Liu, Yan,Cai, Linlin,Cao, Xinyu,Qian, Shan,Wang, Zhouyu
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p. 1713 - 1716
(2021/03/08)
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- Tf2O/TTBP (2,4,6-Tri-tert-butylpyrimidine): An Alternative Amide Activation System for the Direct Transformations of Both Tertiary and Secondary Amides
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Ten types of Tf2O/TTBP-mediated amide transformation reactions were investigated. The results showed that compared with pyridine derivatives 2,6-di-tert-butyl-4-methylpyridine (DTBMP) and 2-fluoropyridine (2-F-Pyr.), TTBP can serve as an alternative amide activation system for the direct transformation of both secondary and tertiary amides. For most surveyed examples, higher or comparable yields were generally obtained. In addition, Tf2O/TTBP combination was used to promote the condensation reactions of 2-(tert-butyldimethylsilyloxy)furan (TBSOF) with both tertiary and secondary amides, the one-pot reductive Bischler-Napieralski-type reaction of tertiary lactams, and Movassaghi and Hill's modern version of the Bischler-Napieralski reaction. The value of the Tf2O/TTBP-based methodology was further demonstrated by the concise and high-yielding syntheses of several natural products.
- He, Qian,Ye, Jian-Liang,Xu, Fang-Fang,Geng, Hui,Chen, Ting-Ting,Chen, Hang,Huang, Pei-Qiang
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- N -Acyliminium Ion Chemistry: Improving the Access to Unsaturated γ-Lactams and Their N -α-Methoxylated Derivatives: Application to an Expeditive Synthesis of (±)-Crispine A
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An improved synthesis of unsaturated γ-lactams by condensation of various primary amines with 2,5-dimethoxy-2,5-dihydrofuran is described. A modified mechanism for this reaction is suggested. Synthesis of their N -α-methoxylated derivatives, as N -acyliminium ion precursors, is also reported. Finally, a short synthesis of (±)-crispine A is presented as an illustrative application.
- Drici, Wassila,Fayssal, Sandra Abi,Lazouni, Imane,Pérard-Viret, Jo?lle,Souquet, Florence,Thueillon, Sébastien
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p. 2970 - 2978
(2020/10/18)
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- Synthetic method of tetrahydroisoquino ring compound and tetrahydro-beta-carbo ring compound
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The invention provides a synthetic method of a tetrahydroisoquino ring compound and a tetrahydro-beta-carbo ring compound, and belongs to the technical field of synthesis. According to the method forsynthesizing the tetrahydroisoquino and the tetrahydro-b
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Paragraph 0047-0052; 0193; 0195-0197
(2020/12/09)
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- Dual Nicotinic Acetylcholine Receptor α4β2 Antagonists/α7 Agonists: Synthesis, Docking Studies, and Pharmacological Evaluation of Tetrahydroisoquinolines and Tetrahydroisoquinolinium Salts
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We describe the synthesis of tetrahydroisoquinolines and tetrahydroisoquinolinium salts together with their pharmacological properties at various nicotinic acetylcholine receptors. In general, the compounds were α4β2 nAChR antagonists, with the tetrahydroisoquinolinium salts being more potent than the parent tetrahydroisoquinoline derivatives. The most potent α4β2 antagonist, 6c, exhibited submicromolar binding Ki and functional IC50 values and high selectivity for this receptor over the α4β4 and α3β4 nAChRs. Whereas the (S)-6c enantiomer was essentially inactive at α4β2, (R)-6c was a slightly more potent α4β2 antagonist than the reference β2-nAChR antagonist DHβη. The observation that the α4β2 activity resided exclusively in the (R)-enantiomer was in full agreement with docking studies. Several of tetrahydroisoquinolinium salts also displayed agonist activity at the α7 nAChR. Preliminary in vivo evaluation revealed antidepressant-like effects of both (R)-5c and (R)-6c in the mouse forced swim test, supporting the therapeutic potential of α4β2 nAChR antagonists for this indication.
- Crestey, Fran?ois,Jensen, Anders A.,Soerensen, Christian,Magnus, Charlotte Busk,Andreasen, Jesper T.,Peters, Günther H. J.,Kristensen, Jesper L.
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supporting information
p. 1719 - 1729
(2018/03/05)
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- α-Alkylation of tertiary amines by C(sp3)–C(sp3) cross-coupling under redox neutral photocatalysis
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Direct α-alkylation of N-phenyl-tetrahydroisoquinoline with alkyl selenides of desired alkyl chain length and functionality is reported by photoredox catalysis. Construction of hexahydro pyrrolo- and pyrido-isoquinoline scaffolds along with indolines and tetrahydroquinolines is also described by intramolecular C(sp3)–C(sp3) cross-couplings.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana
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supporting information
p. 4480 - 4483
(2016/09/14)
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- Synthesis of substituted tetrahydroisoquinolines by lithiation then electrophilic quench
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Substituted N-tert-butoxycarbonyl (Boc)-1,2,3,4-tetrahydroisoquinolines were prepared and treated with n-butyllithium in THF at -50 °C to test the scope of the metallation and electrophilic quench. The lithiation was optimised by using in situ ReactIR spectroscopy and the rate of rotation of the carbamate was determined. The 1-lithiated intermediates could be trapped with a variety of electrophiles to give good yields of 1-substituted tetrahydroisoquinoline products. Treatment with acid or reduction with LiAlH4 allows conversion to the N-H or N-Me compound. The chemistry was applied to the efficient total syntheses of the alkaloids (±)-crispine A and (±)-dysoxyline.
- Talk, Ruaa A.,Duperray, Alexia,Li, Xiabing,Coldham, Iain
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p. 4908 - 4917
(2016/06/13)
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- A Highly Active System for the Metal-Free Aerobic Photocyanation of Tertiary Amines with Visible Light: Application to the Synthesis of Tetraponerines and Crispine A
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A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol % or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctionalization of complex molecules. The catalytic system is furthermore applied in the short and effective syntheses of the alkaloids (±)-crispine A and the tetraponerines T7 and T8.
- Orejarena Pacheco, Julio Cesar,Lipp, Alexander,Nauth, Alexander M.,Acke, Fabian,Dietz, Jule-Philipp,Opatz, Till
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supporting information
p. 5409 - 5415
(2016/04/09)
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- Zinc-catalyzed selective reduction of cyclic imides with hydrosilanes: Synthesis of ω-hydroxylactams
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Cyclic imides were selectively reduced to the corresponding ω-hydroxylactams in high yields with (EtO)3SiH (triethoxysilane) or PMHS (polymethylhydrosiloxane) under catalysis of zinc diacetate dehydrate [Zn(OAc)2 2H2O] (10%) and tetramethylethylenediamine (TMEDA) (10%). This catalytic protocol showed good functional group tolerance as well as excellent regioselectivity for unsymmetrical imides bearing coordinating groups adjacent to the carbonyl.
- Ding, Guangni,Lu, Bin,Li, Yuyuan,Wan, Jun,Zhang, Zhaoguo,Xie, Xiaomin
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p. 1013 - 1021
(2015/03/30)
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- Synthesis of condensed tetrahydroisoquinoline class of alkaloids by employing TfOH-mediated imide carbonyl activation
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Isoquinoline-based polycyclic lactams such as isoindoloisoquinolinones, pyrroloisoquinolinones, and benzo[a]quinolizinones were successfully assembled from the corresponding imides by using a TfOH-mediated (TfOH = trifluoromethanesulfonic acid) imide carbonyl activation and cyclization strategy. By employing this simple method, the isoquinoline alkaloids crispine A, trolline/oleracein E, and erythrinarbine were successfully synthesized in racemic form. The reaction of unsymmetrical N-phenethylphthalimides with TfOH displayed excellent regioselectivity, which was rationalized by DFT calculations.
- Selvakumar, Jayaraman,Rao, Ramana Sreenivasa,Srinivasapriyan, Vijayan,Marutheeswaran, Srinivasan,Ramanathan, Chinnasamy Ramaraj
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p. 2175 - 2188
(2015/04/14)
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- Acid promoted cyclodehydration of amino alcohols with amide acetal
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A convenient acid-promoted cyclization protocol for the formation of azaheterocycles from amino alcohols is described. The reaction involves the use of N,N-dimethylacetamide dimethyl acetal (DMADA) as the activating reagent of the hydroxyl group. Using this protocol, pyrrolidines or piperidines with various substituents can be synthesized in good to high yields.
- Hwang, Soonho,Park, Heemin,Kwon, Yongseok,Kim, Sanghee
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p. 60017 - 60024
(2015/02/19)
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- A general catalytic route to isoindolinones and tetrahydroisoquinolines: Application in the synthesis of (±)-crispine A
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An unprecedented highly efficient Lewis acid catalyzed one-pot cascade has been demonstrated as a general catalytic system for the synthesis of diversely substituted isoindolinones and tetrahydroisoquinolines. The cascade effects one C-C and two C-N bond-
- Dhanasekaran, Sivasankaran,Bisai, Vishnumaya,Unhale, Rajshekhar A.,Suneja, Arun,Singh, Vinod K.
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p. 6068 - 6071
(2015/01/09)
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- Design, synthesis, and biological evaluation of Erythrina alkaloid analogues as neuronal nicotinic acetylcholine receptor antagonists
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The synthesis of a new series of Erythrina alkaloid analogues and their pharmacological characterization at various nicotine acetylcholine receptor (nAChR) subtypes are described. The compounds were designed to be simplified analogues of aromatic erythrinanes with the aim of obtaining subtype-selective antagonists for the nAChRs and thereby probe the potential of using these natural products as scaffolds for further ligand optimization. The most selective and potent nAChR ligand to come from the series, 6,7-dimethoxy-2- methyl-1,2,3,4-tetrahydroisoquinoline (3c) (also a natural product by the name of O-methylcorypalline), displayed submicromolar binding affinity toward the α4β2 nAChR with more than 300-fold selectivity over α4β4, α3β4, and α7. Furthermore, this lead structure (which also has inhibitory activity at monoamine oxidases A and B and at the serotonin and norepinephrine transporters) showed antidepressant-like effect in the mouse forced swim test at 30 mg/kg.
- Crestey, Fran?ois,Jensen, Anders A.,Borch, Morten,Andreasen, Jesper Tobias,Andersen, Jacob,Balle, Thomas,Kristensen, Jesper Langgaard
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supporting information
p. 9673 - 9682
(2014/01/06)
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- Synthesis of new mono-N-tosylated diamine ligands based on (R)-(+)-limonene and their application in asymmetric transfer hydrogenation of ketones and imines
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A synthetic procedure leading to the preparation of a new family of enantiopure mono-N-tosylated-1,2-diamines derived from (R)-(+)-limonene is described. (+)-Limonene was transformed into the appropriate N-tosyl derivative using N-tosylaziridination based on chloramine-T trihydrate. Subsequent ring opening by sodium azide afforded the corresponding isomeric azides. Finally, reduction of the azide function gave enantiomerically pure mono-N-tosylated-1,2- diamines. The ligands obtained proved to be effective in the asymmetric transfer hydrogenation protocol on aromatic ketones and imines.
- Roszkowski, Piotr,Maurin, Jan K.,Czarnocki, Zbigniew
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p. 643 - 650
(2013/07/27)
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- A cascade approach to fused indolizinones through Lewis acid-copper(i) relay catalysis
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A relay catalytic cascade process involving Lewis acid triggered ring-opening of cyclopropyl ketones with nitriles, the copper(i)-catalyzed Ritter process, and acid-promoted N-acyliminium ion cyclization is described, which efficiently provides thieno-, furano-, and benzo-indolizinones in moderate to good yields. The Royal Society of Chemistry 2013.
- Huang, Huawen,Ji, Xiaochen,Wu, Wanqing,Jiang, Huanfeng
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p. 3351 - 3353
(2013/06/04)
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- Silver(i)-promoted oxidative cyclisation to pyrrolo[2,1-a]isoquinolines and application to the synthesis of (±)-crispine A
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The silver(i)-promoted oxidative cyclisation of 1-propargyl-substituted tetrahydroisoquinolines affords pyrrolo[2,1-a]isoquinolines. Scope and limitations of this method are described and an application to the synthesis of the natural product (±)-crispine A is presented. The Royal Society of Chemistry 2013.
- Agarwal, Sameer,Kataeva, Olga,Schmidt, Ulrike,Knoelker, Hans-Joachim
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p. 1089 - 1096
(2013/03/14)
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- Iron-catalyzed oxidative coupling of alkylamides with arenes through oxidation of alkylamides followed by Friedel-Crafts alkylation
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FeCl3 in combination with t-BuOOt-Bu as an oxidant was found to be an efficient catalyst for oxidation of alkylamides to α-(tert-butoxy) alkylamides. FeCl2 and CuCl showed, respectively, almost the same and slightly lower activities
- Shirakawa, Eiji,Uchiyama, Nanase,Hayashi, Tamio
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- Synthesis of (±)-crispine A via a nitrosoalkene hetero-Diels-Alder addition to ethyl vinyl ether
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The synthesis of (±)-crispine A in 9 steps and 24% overall- yield was achieved using a nitrosoalkene hetero-Diels-Alder- addition to ethyl vinyl ether as the key step. The synthesis starts from commercial 3,4- dimethoxyphenylacetic acid and uses simple me
- Yioti, Efthymia G.,Mati, Ioulia K.,Arvanitidis, Athanassios G.,Massen, Zoe S.,Alexandraki, Elli S.,Gallos, John K.
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body text
p. 142 - 146
(2011/02/26)
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- Diastereoselective cycloadditions and transformations of N -alkyl and N -aryl maleimides with chiral 9-anthrylethanol derivatives
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Figure presented. Thermal Diels-Alder reactions of chiral 9-methoxyethyl and 9-hydroxyethyl anthracene have been investigated both experimentally and computationally with a range of N-substituted maleimides. Whereas cycloadditions with 9-methoxyethyl anthracene proceeded with almost complete diastereselectivity, those with 1-anthracene-9-yl-ethanol resulted in essentially no diastereoselectivity. Subsequent regio- and stereoselective transformations with reducing agents and carbon nucleophiles demonstrated the synthetic utility of this methodology, which was applied to the enantioselective synthesis of pyrrolo[2,1-a]isoquinolines and an attempted synthesis of the alkaloid crispine A. Computational studies supported the proposed hypotheses for the stereoselectivity observed in the transformations described.
- Adams, Harry,Elsunaki, Tareg M.,Ojea-Jimenez, Isaac,Jones, Simon,Meijer, Anthony J. H. M.
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experimental part
p. 6252 - 6262
(2010/11/20)
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- Cascade condensation, cyclization, intermolecular dipolar cycloaddition by multi-component coupling and application to a synthesis of (±)-crispine A
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A general approach for the synthesis of various nitrogen-containing heterocyclic compounds is described using an intermolecular dipolar cycloaddition reaction of azomethine ylides and nitrones. Stabilized and non-stabilized azomethine ylide dipoles or the related nitrones were generated by condensation of 4-, 5- or 6-halo-aldehydes with a readily available amino-acid, amino-ester or hydroxylamine to give an imine followed by cyclization and either decarboxylation or loss of a proton. After intermolecular cycloaddition with an activated dipolarophile, bicyclic or polycyclic (if the ylide dipole and/or dipolarophile contain a ring) amines were produced. A short synthesis of the alkaloid (±)-crispine A was achieved based on this tandem/domino 3-component coupling chemistry.
- Coldham, Iain,Jana, Samaresh,Watson, Luke,Martin, Nathaniel G.
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experimental part
p. 1674 - 1679
(2009/06/27)
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- A highly enantioselective access to tetrahydroisoquinoline and β-carboline alkaloids with simple noyori-type catalysts in aqueous media
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Silver enhancement: A very convenient modified protocol for the enantioselective transfer hydrogenation of dihydroisoquinoline skeletons under aqueous conditions is reported. Unmodified Noyori ligands can be used and the activity of the catalyst is greatly enhanced with silver additives (see scheme). The protocol was used in a very short synthesis of the alkaloids (S)-harmicine and (S)-crispine.
- Evanno, Laurent,Ormala, Joel,Pihko, Petri M.
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supporting information; experimental part
p. 12963 - 12967
(2010/06/16)
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- Efficient syntheses of crispine A and harmicine by Rh-catalyzed cyclohydrocarbonylation
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The first examples of Rh-catalyzed cyclohydrocarbonylation-bicyclization of N-allylic amides of arylacetic acids are reported. This novel carbonylative bicyclization process was successfully applied to the rapid syntheses of crispine A and its analogues (
- Chiou, Wen-Hua,Lin, Gau-Hong,Hsu, Che-Cheng,Chaterpaul, Stephen J.,Ojima, Iwao
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supporting information; experimental part
p. 2659 - 2662
(2009/10/02)
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- Chlorination/cyclodehydration of amino alcohols with SOCl2: An old reaction revisited
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(Chemical Equation Presented) A simple, one-pot preparation of cyclic amines via efficient chlorination of amino alcohols with use of SOCl2 has been developed. This approach obviates the need for the classical N-protection/O-activation/cyclization/deprotection sequence commonly employed for this type of transformation. The reaction pathways and the general scope of this method have also been investigated.
- Xu, Feng,Simmons, Bryon,Reamer, Robert A.,Corley, Edward,Murry, Jerry,Tschaen, David
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p. 312 - 315
(2008/09/17)
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- Attempts to mimic key bond-forming events associated with the proposed biogenesis of the pentacyclic lamellarins
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The pyrrole-tethered veratroles 16 and 27 each engage in PIFA-induced oxidative cyclization reactions to give compounds 22 and 29, respectively, which incorporate a key tricyclic fragment associated with the title natural products. In contrast, the corresponding catechols 11 and 12 only produce polymeric materials on subjection to analogous reaction conditions. Efforts to study lactone ring formation by the oxidative cyclization of catechol 30 and veratrole 38 have been thwarted by an inability to prepare the former substrate and decomposition of the latter. The reported conversions 44 ? 45 and 46 ? 47 suggest that a C2-carboxy group attached to the pyrrole ring can ?direct' the oxidative cyclization of N-tethered aryl groups. The acquisition of compound 22 by the means described herein provides an adventitious and concise route to the racemic modification of the pyrrolo[2,1-a]isoquinoline alkaloid crispine A (52). CSIRO 2008.
- Axford, Lorraine C.,Holden, Kate E.,Hasse, Katrin,Banwell, Martin G.,Steglich, Wolfgang,Wagler, Joerg,Willis, Anthony C.
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- A facile three-step synthesis of (±)-crispine A via an acyliminium ion cyclisation
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A high yielding cyclisation of the readily available N-(4,4-diethoxybutyl)-2-(3,4-dimethoxyphenyl)acetamide to 8,9-bis(methyloxy)-2,3,6,10b-tetrahydropyrrolo[2,1-a]isoquinolin-5(1H)-o ne is described. The latter can be reduced with either AlH3
- King, Frank D.
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p. 2053 - 2056
(2007/10/03)
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- A template-based mnemonic for monoamine oxidase (MAO-N) catalyzed reactions and its application to the chemo-enzymatic deracemisation of the alkaloid (±)-crispine A
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A template-based mnemonic has been developed for the enzyme monoamine oxidase from Aspergillus niger and has been used to successfully identify the alkaloid (±)-crispine A as a target for chemo-enzymatic deracemisation yielding the biologically active (R)
- Bailey, Kevin R.,Ellis, Andrew J.,Reiss, Renate,Snape, Timothy J.,Turner, Nicholas J.
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p. 3640 - 3642
(2008/03/14)
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- STUDIES ON FRIEDEL-CRAFTS ACYLATION OF N-ACETYLHOMOVERATRYLAMINE AND PREPARATION OF 1-SUBSTITUTED 3,4-DIHYDRO-6,7-DIMETHOXYISOQUINOLINES
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Friedel-Crafts acylation of N-acetylhomoveratrylamine in a molar ratio of 1:2:3 of 1, AlCl3 and the appropriate acid chloride using nitrobenzene as solvent gave the corresponding 2-acyl derivatives 2a-j in good yields.Subsequent treatment of 2 in boiling
- Orito, Kazuhiko,Matsuzaki, Tsutomu,Suginome, Hiroshi,Rodrigo, Russel
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p. 2403 - 2412
(2007/10/02)
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- Use of Chloroalkenylamines for the Synthesis of 1-Azabicyclooctane and 1-Azabicyclononane Derivatives
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Various N-(chloroprop-2-enyl)-, N-(3-chlorobut-2-enyl)-, N-(4-chloropent-3- and -4-enyl)-proline derivatives, -succinimides, and -phthalimides have been synthesised and subjected to Lewis acid treatment.The following gave fruitful results: N-(4-chloropent-3-enyl)-5-hydroxy-2-pyrrolidone (25) gave 1-acetyl-1,2,3,6,7,7a-hexahydropyrrolizin-5-one (28); N-(4-chloropent-3-enyl)-3-hydroxy-2,3-dihydro-1H-isoindol-1-one (30) gave 1-endo-acetyl-1,2,3,9b-tetrahydropyrroloisoindol-5-one (31) which was isomerised to the exo-isomer; N-(4-chloropent-3-enyl)-3-methylene-2,3-dihydro- 1H-isoindol-1-one (34) and N-(4-chloropent-3-enyl)-3-hydroxy-3-methyl-2,3-dihydro-1H-isoindol-1-one (33) gave 1-endo-acetyl-9b-methyl-1,2,3,9b-tetrahydropyrroloisoindol-5-one (35); N-proline (42) gave 8,9-dimethoxy-1,2,3,5,6,10b-hexahydropyrroloisoquinoline (43), N-(2-chloroprop-2-enyl)-2-(2-hydroxy-2-propyl)pyrrolidine (44) gave 6-chloro-8,8-dimethyl-1,2,3,5,8,8a-hexahydroindolizine (47) and 8,8-dimethyl-1,2,3,7,8,8a-hexahydroindolizin-6(5H)-one (48) which were reduced to the corresponding alcohols; N-(4-chloropent-4-enyl)-3-hydroxy-2,3-dihydro-1H-isoindol-1-one (50) gave 7,8,11,11a-tetrahydro-5H-azepinoisoindole-5,10(9H)-dione (51).
- Lochead, Alistair W.,Proctor, George R.,Caton, Michael P. L.
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p. 2477 - 2489
(2007/10/02)
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- Photosolvolysis of Bridgehead Quaternary Ammonium Salts.I. Synthesis of Some 3-Benzazonine Derivatives
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The medium-ring heterocyclic derivative 7,9,10-trimethoxy-3-methyl-2,3,4,5,6,7-hexahydro-1H-3-benzazonine (10a) was obtained from the ultraviolet irradiation of the reduced pyrroloisoquinolinium iodide salt (9a) in methanol, along with N-2-(3,4-di
- Bremner, John B.,Winzenberg, Kevin N.
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p. 1203 - 1215
(2007/10/02)
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- N-CHLORAMINE REARRANGEMENTS. THE USE OF CYCLOBUTYLAMINE AS A PYRROLIDEINE PRECURSOR.
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Exposure of N-chloro-N-cyclobutyl-3,4-dimethoxyphenethylamine to silver ion in benzene results in efficient ring expansion to a pyrrolideine that can be trapped via Pictet-Spengler reaction.
- Schell, Fred M.,Smith, Anita M.
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p. 1883 - 1884
(2007/10/02)
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- Novel Zinc-Promoted Alkylation of Iminium Salts. New Synthesis of Benzylisoquinoline, Phthalidylisoquinoline, and Protoberberine Alkaloids and Related Compounds
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Zinc-promoted reductive coupling reaction of iminium salts with alkyl halides was found to be a successful key reaction for synthesis of a variety of alkaloids such as benzylisoquinoline, phthalidylisoquinoline, and protoberberine alkaloids.More specifically, laudanosine, cordrastine, hydrastine, narcotine, tetrahydropalmatine, and canadine were obtained.A new route for the synthesis of the emetine and yohimbine skeletons was exploited.
- Shono, Tatsuya,Hamaguchi, Hiroshi,Sasaki, Manji,Fujita, Shumei,Nagami, Kimihiko
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p. 1621 - 1628
(2007/10/02)
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