- Synthesis of heterocyclic enamine-zinc complexes as precursors of stereocontrolled substitution of nitrogen α-position
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In the presence of ZnCl2, chiral protected amino-ketones and amino-aldehydes gave zinc enamino-complexes. Both enamine and iminium structures of these complexes were observed in 1H and 13C NMR spectra depending on the solvent. Introduction of either an allyl or a hydrogen substituent was performed using allylmagnesium chloride or NaBH4 in excess leading to various heterocycles. With the amino-ketones diastereoselectivity (de = 50) was observed respectively. Homoconiine and coniine precursors were prepared by this strategy.
- Graton, Jér?me,Jacquemin, Denis,Renault, Jacques,Tran, Hoang-Van,Uriac, Philippe,Vu, Huy-Dinh
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Read Online
- AMMONIUM SALT, ELECTROLYTE FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY USING THEM
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PROBLEM TO BE SOLVED: To provide: ammonium salt with low viscosity; an electrolyte for a lithium secondary battery; and the lithium secondary battery. SOLUTION: This invention relates to an ammonium salt expressed by the following chemical formula (1). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
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Paragraph 0075
(2017/12/01)
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- A3-coupling reaction as a strategy towards the synthesis of alkaloids
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A number of aldehydes, alkynols and benzylamines were submitted to A3-coupling reaction, under CuCl catalysis, giving strategically functionalized hydroxy-propargylamines. The procedure allows the use of alkyl as well as aryl aldehydes. Representative substrates were converted into five- and six-membered cyclic alkaloids by sequential one-pot N-debenzylation/triple bond reduction promoted by Pd, followed by a Mitsunobu-type cyclization.
- Carmona, Rafaela C.,Wendler, Edison P.,Sakae, George H.,Comassetoa, Jo?o V.,Santos, Alcindo A. Dos
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p. 117 - 123
(2015/02/19)
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- Proline catalyzed, one-pot three component Mannich reaction and sequential cyclization toward the synthesis of 2-substituted piperidine and pyrrolidine alkaloids
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Abstract A very effective one-pot three component reaction of 4-bromobutanal or 5-bromopentanal, acetone, and p-anisidine catalyzed by proline is reported. A three component Mannich reaction followed by cyclization leading to the synthesis of 2-substituted pyrrolidine and piperidine derivatives through simultaneous formation of two C-N and one C-C bond is reported. The usefulness of the reaction is demonstrated by the synthesis of (±)coniine, (±)pelletrine, (±)sedridine, and (±)allosedridine.
- Chacko, Shibin,Ramapanicker, Ramesh
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supporting information
p. 2023 - 2026
(2015/03/18)
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- Studies on difficult intramolecular hydroaminations in the context of four syntheses of alkaloid natural products
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Examples of intramolecular alkene hydroaminations forming six-membered ring systems are rare, especially for systems in which the double bond is disubstituted. Such cyclizations have important synthetic relevance. Herein we report a systematic study of these cyclizations using recently developed Cope-type hydroamination methodologies. Difficult intramolecular alkene hydroaminations were used as key steps in syntheses of 2-epi-pumiliotoxin C, coniine, N-norreticuline and desbromoarborescidine A. This effort required the development of optimized hydroamination conditions to improve the efficiency of the cyclizations. Collectively, our results show that Cope-type cyclizations can be achieved on a variety of challenging substrates and proceed under similar conditions for both N-H and N-substituted hydroxylamines.
- Dion, Isabelle,Vincent-Rocan, Jean-Francois,Zhang, Lei,Cebrowski, Pamela H.,Lebrun, Marie-Eve,Pfeiffer, Jennifer Y.,Bedard, Anne-Catherine,Beauchemin, Andre M.
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p. 12735 - 12749
(2014/01/17)
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- A concise and diastereoselective synthesis of piperidine and indolizidine alkaloids via aza-Prins cyclization
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The synthesis of 2-substituted and 2,4-disubstituted piperidine alkaloids such as (±)-coniine, (±)-hydroxypipecolic acid, (±)-pipecolic acid, (±)-coniceine, and (±)-4-hydroxy-2- hydroxy-methyl piperidine have been accomplished in a highly diastereo-selective manner by employing aza-Prins cyclization as a key step to construct the piperidine core of these alkaloids. Georg Thieme Verlag Stuttgart · New York.
- Reddy, Basi V. Subba,Chaya, Dudhmal N.,Yadav, Jhillu S.,Gree, Rene
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p. 297 - 303
(2012/03/26)
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- Hydroformylation of alkenylamines. Concise approaches toward piperidines, quinolizidines, and related alkaloids
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Linear hydroformylation of N-protected allyl- or homoallylamines (cyclohydrocarbonylation: CHC), followed by a reductive amination constitute the two key steps toward convenient routes to aza-heterocycles.
- Airiau, Etienne,Girard, Nicolas,Pizzeti, Marianna,Salvadori, Jessica,Taddei, Maurizio,Mann, Andre
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supporting information; experimental part
p. 8670 - 8673
(2011/02/28)
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- High regioselectivity in electrochemical α-methoxylation of N-protected cyclic amines
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N-Protecting groups of α-substituted cyclic amines strongly affected the regioselectivity in electrochemical methoxylation of these compounds. Namely, N-acyl derivatives were transformed into α′-methoxylated compounds, while N-cyano derivatives changed into α-methoxylated derivatives. Furthermore, Lewis acid catalyzed nucleophilic substitution of the α-methoxylated compounds protected with cyano group afforded α,α-disubstituted cyclic amines.
- Libendi, Samuel S.,Demizu, Yosuke,Matsumura, Yoshihiro,Onomura, Osamu
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p. 3935 - 3942
(2008/09/20)
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- Dearomatization of N-phenyl-2,6-dialkylpiperidines: Practical synthesis of (±)-solenopsin A and (±)-dihydropinidine
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The fire ant venom alkaloid (±)-solenopsin A was prepared in 4 steps (34%) starting from the N-phenyl-2-undecyl piperidine (1c). The key step in this synthesis involved the dearomatization of the phenyl group of N-phenyl-2-methyl-6-undecyl-piperidine (9c), which was carried out under Birch conditions.
- Girard, Nicolas,Gautier, Cyrille,Malassene, Richard,Hurvois, Jean-Pierre,Moinet, Claude,Toupet, Loic
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p. 2005 - 2009
(2007/10/03)
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- Novel 3-phenylprop-2-ynylamines as inhibitors of mammalian squalene epoxidase.
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The synthesis of a novel series of 3-phenylprop-2-ynylamines as selective mammalian squalene epoxidase inhibitors is described. Structure activity relationship studies led to the discovery of compound 19, 1-[3-(3,5-dichlorophenyl)-prop-2-ynyl]-3- methylpiperidine hydrochloride with an IC50 of 2.8 +/- 0.6 microM against rat liver squalene epoxidase. Against 23 strains of fungal squalene epoxidase compound 19 was found to be inactive.
- Musso, David L,Clarke, Morris J,Kelley, James L,Boswell, G Evan,Chen, Grace
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p. 498 - 506
(2007/10/03)
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- Asymmetric total synthesis of (R)-(-)-cryptopleurine and (R)-(-)-julandine via highly enantioselective amidoalkylations with N-acylhydrazonium salts
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The first enantioselective total syntheses of the phenanthroquinolizidine alkaloid (-)-cryptopleurine (1) and its seco base (-)-julandine [(R)-3] are described. The synthesis of (R)-3 allowed the 9aS configuration to be assigned to natural dextrorotatory julandine as shown by structure (S)-3. Both synthetic approaches are based on the high degree of 1,3-asymmetric induction achieved using an N-acylhydrazonium salt, which belongs to a new structural class of activated azomethines. Upon exposure of methoxylactam 9, with a chiral 2-substituted pyrrolidine auxiliary, to BF3·Et2O and a silyl enol ether the in situ generated N-acylhydrazonium intermediate 10 underwent asymmetric nucleophilic addition to give the (6R)-keto lactams 13 and 14 with complete diastereoselectivity. On the other hand, nucleophilic addition to the N-acylhydrazonium ion 25, with an acyclic chiral auxiliary, showed poor diastereoselectivity. From these results, the high degree of diastereoselection observed for the N-acylhydrazonium ion 10 can be rationalized in terms of the pyramidal stability of the trivalent nitrogen in the chiral pyrrolidine auxiliary. Removal of the chiral auxiliary from 13 and 14 was achieved by reductive N-N bond cleavage using BH3·THF, affording (2S)-piperidine derivatives 15 and 31, respectively, which were transformed into quinolizidinones 30 and 35, respectively, via intramolecular aldol condensation. Reduction of 30 with alane provided (-)julandine [(R)-3]. In addition, 35 was converted to (-)-cryptopleurine (1) in two steps, by radical cyclization with Bu3SnH and AIBN, followed by LiAlH4 reduction.
- Suzuki,Aoyagi,Kibayashi
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p. 6114 - 6122
(2007/10/03)
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- Titanium(III)-induced transformation of hydroxylamines to imines or secondary amines
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N,N-Disubstituted and cyclic hydroxylamines can be converted into the corresponding imines efficiently upon treatment with anhydrons titanium trichloride in THF at room temperature. Similar treatment of N-allylhydroxylamines with anhydrous titanium trichloride gives 1-azadienes, which are versatile synthetie intermediates for aza-Diels-Alder reactions. On the other hand, the same hydroxylamines can be converted into the corresponding secondary amines upon treatment with aqueous titanium trichloride in methanol. It is noteworthy that optically active hydroxylamines, which have chirality at the α-position to nitrogen, can be converted into optically active secondary amines without loss of chirality. Dihydro-2(1H)-quinolinones can be prepared upon treatment of 1-hydroxy-3,4-dihydro-2(1H)-quinolinones with aqueous titanium trichloride. The substrates of N,N-disubstituted and cyclic hydroxylamines can be prepared readily upon treatment of nitrones with nucleophiles. Since nitrones can be prepared by metal-catalyzed oxidations of secondary amines with hydrogen peroxide, the present titanium(III)-promoted reaction of hydroxylamines will provide a convenient method for the synthesis of either α-substituted imines or amines from secondary amines.
- Kodera,Watanabe,Imada,Murahashi
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p. 2542 - 1549
(2007/10/02)
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- Electrophilic formamidines. Organometallic addition to 2-methoxy pyrrolidine or piperidine N-t-butyl formamidines. Formation of 2-substituted pyrrolidines and piperidines
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The title compounds were prepared by addition of Grignard reagents to methoxyformamidines 6 and 8 in ether at room temperature. Hydrolysis gives the free secondary amines, or in cases of volatile products, their thiourea derivatives.
- Gottlieb,Meyers
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p. 4723 - 4726
(2007/10/02)
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- APPLICATION OF TiCl4 INDUCED IMINIUM ION CYCLIZATIONS TO THE PREPARATIONS OF PIPERIDINE ALKALOIDS: TOTAL SYNTHESES OF (+/-)-CONIINE
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Syntheses of (+/-)-coniine via TiCl4 induced iminium ion cyclizations of α-cyanoamines are described.Moreover, (α-cyanoalkyl)amine could lead to the cyclic piperidine system in good yields.
- Teng, Tsung-Fan,Lin, Jyh-Hwa,Yang, Teng-Kuei
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p. 1201 - 1204
(2007/10/02)
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- Alkynylation of Thiolactams. New Synthesis of α-Substituted Pyrrolidine and Piperidine Alkaloids
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Alkynylation of S-alkylthioamidium salts of thiolactams with lithium acetylides followed by reduction with LiAlH4 provided α-alkynylazacycloalkanes, which on reduction, or hydroboration followed by oxidation, gave α-substituted pyrrolidine and piperidine alkaloids.
- Takahata, Hiroki,Takahashi, Koichi,Wang, Eng-Chi,Yamazaki, Takao
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p. 1211 - 1214
(2007/10/02)
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- Introduction of alkyl groups at the α-positions of pyrrolidines and piperidines: Synthesis of (±)-coniine
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The conversion of lactams to α-alkylated cyclic amines is described. Reactions of α-ethoxyurethanes with trimethylsilyl cyanide in the presence of Lewis acid afford the corresponding α-cyanourethanes, which, via carbanion, are alkylated to α-alkyl-α-cyanourethanes in moderate to high yields. Syntheses of (±)-coniine and trans-quinolizidine are carried out as model experiments for dealkoxycarbonylation and decyanation of 2-alkyl-1-alkoxycarbonyl-2-cyanopiperidines.
- Nagasaka, Tatsuo,Hayashi, Hideki,Hamaguchi, Fumiko
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p. 1685 - 1696
(2007/10/02)
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- Efficient and Convenient Method for Synthesis of Solenopsin A and Its Analogues Using 1-Benzyl-2,6-dicyanopiperidine
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An efficient synthetic sequence proposed here provides a new method for preparation of not only solenopsin A, i.e., trans-2-methyl-6-undecylpiperidine, but also coniine, i.e., 2-propylpiperidine, and other 2,6-dialkylpiperidine alkaloids: A reaction of 1-benzyl-2,6-dicyanopiperidine (1) with alkyl halides selectively gives 2-alkyl- and 2,6-dialkyl-1-benzyl-2,6-dicyanopiperidines (2 and 3), decyanation of which affords respectively 2-alkyl- and 2,6-dialkyl-1-benzylpiperidines (4 and 5) in high yields.
- Takahashi, Kazumasa,Kurita, Hideki,Ogura, Katsuyuki,Iida, Hirotada
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p. 4368 - 4371
(2007/10/02)
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- TITANIUM(III) INDUCED TRANSFORMATIONS OF N,N-DISUBSTITUTED HYDROXYLAMINES TO IMINES AND SECONDARY AMINES
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The reaction of N,N-disubstituted hydroxylamines with anhydrous TiCl3 gives the corresponding imines, while that with aqueous TiCl3 gives secondary amines.
- Murahashi, Shun-Ichi,Kodera, Yoichi
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p. 4633 - 4636
(2007/10/02)
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- Constitution of Hofmann's Dimethylconiine and Conylene
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Hofmann's "dimethylconiine" is confirmed as a mixture of 5-N,N-dimethylamino-oct-1-ene (2), (E)-1-N,N-dimethylamino-oct-4-ene (3), and (E)-1-N,N-dimethylamino-oct-5-ene (4). "Conylene" is a mixture of (2E,4E)- and (2Z,4E)-octa-2,4-dienes (11) and (12) respectively, (E)-octa-1,4-diene (13), and, probably, (E)-octa-1,5-diene (14).
- Cocker, Wesley,Geraghty, Niall W. A.,Shannon, Patrick V. R.
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p. 2241 - 2244
(2007/10/02)
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- Optical Rotatory Dispersion and Absolute Configuration. Part 35. Chiroptical Properties and Conformation of Indolizidine
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1H N.m.r. spectroscopy at 360 MHz confirms that indolizidine is trans-fused with the piperidine ring in a chair conformation.The pyrrolidine ring adopts an envelope conformation with the nitrogen atom displaced out of the plane of the four carbon atoms of the ring.An improved synthesis of (+)- and (-)-indolizidine from (-)- and (+)-coniine is described.The o.r.d. and c.d. spectra of indolizidine are compared with those of coniine.
- Ringdahl, Bjorn,Pinder, A. Reginald,Pereira, Wilfred E.,Oppenheimer, Norman J.,Craig, John Cymerman
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- Addition of Allylboronates to Schiff Bases and to Oximes
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Clean addition of allylboronates of Type 3 to Schiff bases 2 leads to the secondary homoallylamines 4.Analogous addition to the oximes 9 results in the formation of the hydroxylamines 13.The latter allow the generation of the primary homoallylamines 14.
- Hoffmann, Reinhard W.,Eichler, Guenter,Endesfelder, Andreas
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p. 2000 - 2007
(2007/10/02)
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- Organoaluminum-Promoted Beckmann Rearrangement of Oxime Sulfonates
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The Beckmann rearrangement of oxime sulfonates with simultaneous nucleophilic trapping of the intermediary iminocarbocation by organoaluminum reagents is described.This process provides a new and highly efficient route to imino thioethers, imino selenoethers, imino nitriles, and α-alkylated amines starting from oxime sulfonates by the use of dialkylaluminum thiolates, selenolates, diethylaluminum chloride-trimethylsilyl cyanide, and trialkylaluminum-diisobutylaluminum hydride systems, respectively.The present organoaluminum-promoted Beckmann rearrangement of oxime sulfonates has been successfully applied to the synthesis of naturally occuring alkaloids, pumiliotoxin C and solenopsin A and B, in stereoselective fashion.Moreover, α,α-dialkylation of amines can be realized by the successive treatment of oxime sulfonates with trialkylaluminum followed by allylic or propargylic Grignard reagents in synthetically useful yields.
- Maruoka, Keiji,Miyazaki, Tohru,Ando, Mamoru,Matsumura, Yasushi,Sakane, Soichi,et al.
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p. 2831 - 2843
(2007/10/02)
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