- Biomimetic synthesis of 2-substituted N-heterocycle alkaloids by one-pot hydrolysis, transamination and decarboxylative Mannich reaction
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Heterocycles based on piperidine and pyrrolidine are key moieties in natural products and pharmaceutically active molecules. A novel multi-enzymatic approach based on the combination of a lipase with an α,ω-diamine transaminase is reported, opening up the synthesis, isolation and characterisation of a broad range of 2-substituted N-heterocycle alkaloids.
- Galman, James L.,Slabu, Iustina,Parmeggiani, Fabio,Turner, Nicholas J.
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supporting information
p. 11316 - 11319
(2018/10/24)
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- Biomimetic Approach toward the Total Synthesis of rac-2-(Acylmethylene)pyrrolidine Alkaloids
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2-(Acylmethylene)pyrrolidine derivatives were synthesized via intermolecular decarbonylative Mannich reaction from various methyl ketones and 1-alkyl-1-pyrroliniums, generated in situ from 1-alkylprolines. This approach mimics the biosynthetic pathway and provides a direct access to a series of 2-(acylmethylene)pyrrolidine alkaloids, including hygrine, N-methylruspolinone, dehydrodarlinine, and ruspolinone.
- Shih, Yu-Chiao,Tsai, Pei-Hua,Hsu, Chia-Chun,Chang, Chih-Wei,Jhong, Yuandong,Chen, Yun-Chung,Chien, Tun-Cheng
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p. 6669 - 6678
(2015/10/06)
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- Total synthesis of the tylophora alkaloids rusplinone, 13aα- secoantofine, and antofine using a multicatalytic oxidative aminochlorocarbonylation/Friedel-Crafts reaction
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A rapid synthetic approach to the tylophora alkaloids antofine and 13aα-secoantofine is presented that makes use of a multicatalytic oxidative aminochlorocarbonylation/Friedel-Crafts reaction as the key step. This reaction, along with a one-pot, three-ste
- Ambrosini, Lisa M.,Cernak, Tim A.,Lambert, Tristan H.
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experimental part
p. 4882 - 4887
(2010/08/06)
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- Synthesis, in vitro and in vivo cytotoxicity of 6,7-diaryl-2,3,8,8a-tetrahydroindolizin-5(1H)-ones
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A 6,7-diaryl-2,3,8,8a-tetrahydroindolizin-5(1H)-one library was constructed and tested against the colon cancer cell line HCT-116 as an initial screen for cytotoxic properties. Of this library, the parent compound, in which the southern aromatic ring remains unsubstituted, and the northern aromatic ring carries a 4-methoxy group, exhibited the most potent cytotoxicity with an IC50 value of 0.39 μM and displayed promising activity in vivo in the NCI's mouse hollow fiber assay.
- Kimball, F. Scott,Tunoori, Ashok Rao,Victory, Samuel F.,Dutta, Dinah,White, Jonathan M.,Himes, Richard H.,Georg, Gunda I.
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p. 4703 - 4707
(2008/02/12)
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- Novel 6,7-diphenyl-2,3,8,8a-tetrahydro-1H-indolizin-5-one analogues as cytotoxic agents
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A series of 6,7-diphenyl-2,3,8,8a-tetrahydro-1H-indolizin-5-one analogues were synthesized and evaluated for cytotoxic activity against eight human cancer cell lines. Compounds 18, 21, 28, 29, 30 and 31 showed cytotoxic activity with GI50 value
- Sharma, Vedula M.,Adi Seshu,Vamsee Krishna,Prasanna,Chandra Sekhar,Venkateswarlu,Rajagopal, Sriram,Ajaykumar,Deevi, Dhanvanthri S.,Rao Mamidi,Rajagopalan
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p. 1679 - 1682
(2007/10/03)
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- Dramatically different photochemical behaviour of 1-aroyl-2-methylene piperidine and pyrrolidine derivatives. An expeditious synthesis of ruspolinone
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Upon irradiation in neutral solvent, the diversely substituted 1-aroyl-2-methylenepiperidines 6a-f give rise to photocyclized products 4a-f while their pyrrolidine congeners 7a,c,d afford enaminoketones 18a,c,d products of photo-Fries rearrangement.
- Couture,Deniau,Grandclaudon,Lebrun
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p. 7749 - 7752
(2007/10/03)
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- Substitution reactions of 2-phenylsulphonyl-piperidines and -pyrrolidines with carbon nucleophiles: Synthesis of the pyrrolidine alkaloids norruspoline and ruspolinone
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Several 2-phenylsulphonyl-piperidines and -pyrrolidines were prepared from the corresponding N-acyl aminals by treatment with benzenesulphinic acid. On reaction with various carbon nucleophiles these sulphones gave good yields of substitution products. Typical nucleophiles used in these studies were organometallic reagents derived from Grignard reagents and zinc halide together with silyl enol ethers, silyl ketene acetals, allylsilanes and trimethylsilyl cyanide in the presence of a Lewis acid. These methods were employed in the synthesis of two natural product alkaloids; Norruspoline (38) and Ruspolinone (40).
- Brown, Dearg S.,Charreau, Philippe,Hansson, Thomas,Ley, Steven V.
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p. 1311 - 1328
(2007/10/02)
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- Phenanthroindolizidine and Related Alkaloids: Synthesis of Tylophorine, Septicine, and Deoxytylophorinine
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Tylophorine (1) is synthesized in two ways.The first method begins with the synthesis of the amide-ester (7), which on reaction, successively, with triethyloxonium fluoroborate and sodium borohydride, gives the aminoester (8) selectively; hydrolysis and polyphosphoric acid-catalysed ring-closure of compound (9) gives the ketone (10) which yields tylophorine (1) on Clemmensen reduction.An alternative approach is by a biogenetically patterned sequence which involves condensation of (3,4-dimethoxybenzoyl)acetic acid (26) with 1-pyrroline (24) generated either in situ from putrescine by pea-seedling diamine oxidase or from ornithine by oxidation with N-bromosuccinimide; the product (16) condenses with 3,4-dimethoxyphenylacetaldehyde in benzene to give an enamine .This undergoes cyclisation and dehydration in methanol; sodium borohydride reduction then gives the alkaloid septicine (19) which, on oxidation with thallium(III) trifluoroacetate, yields tylophorine (1).Deoxytylophorinine (34) is made in an exactly analogous manner to the latter method for tylophorine.
- Cragg, John E.,Herbert, Richard B.,Jackson, Frederick B.,Moody, Christopher J.,Nicolson, Ian T.
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p. 2477 - 2486
(2007/10/02)
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- BIOSYNTHESIS OF TYLOPHORINE AND TYLOPHORININE
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Administration of 3,4-dihydroxyphenyl(2-(14)C)alanine to young Tylophora asthmatica plants revealed that ring B and carbon atoms C9 and C7' of tylophorine and tylophorinine are derived from dopa.Tracer experiments with 6,7-diphenylhe
- Bhakuni, Dewan S.,Mangla, Virendra K.
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p. 401 - 407
(2007/10/02)
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- A New Synthesis of Septicine, a Secophenanthroindolizine Alkaloid
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Septicine , an alkaloid isolated from Ficus septica and Tylophora asthmatica, has been synthesized using 2-(3',4'-dimethoxyphenacyl)pyrrolidine (6) and 3,4-dimethoxy-phenylacetyl chloride (11) as the essential intermediates.Condensation of 6 and 11 affords 2-(3',4'-dimethoxyphenacyl)-N-(3'',4''-dimethoxyphenylacetyl)pyrrolidine (12) which on treatment with potassium-t-butoxide furnishes 6,7-di-(3',4'-dimethoxyphenyl)-5-oxo-1,2,3,5,8,8a-hexahydroindolizine (13).LAH reduction of 13 affords septicine (1), identical (co-TLC, IR, PMR, m.m.p.) with a natural sample.
- Mangla, V. K.,Bhakuni, D. S.
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p. 748 - 749
(2007/10/02)
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