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Anthony C. Willis - One of the best experts on this subject based on the ideXlab platform.
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Application of Electrocyclic Ring-Opening and Desymmetrizing Nucleophilic Trappings of meso-6,6-Dibromobicyclo[3.1.0]hexanes to Total Syntheses of Crinine and Haemanthamine Alkaloids
Journal of Organic Chemistry, 2019Co-Authors: Martin G. Banwell, Anthony C. WillisAbstract:The thermally induced electrocyclic ring-opening of C2-symmetric (meso) 6,6-dibromobicyclo[3.1.0]hexanes such as 10 in the presence of the chiral, nonracemic 1°-amine 28 afforded a ca. 1:1 mixture of the diastereoisomeric and chromatographically separable 1-amino-2-bromo-2-cyclohexenes 37 (42%) and 38 (45%). Each of these was elaborated over 13 steps, including Suzuki–Miyaura cross-coupling, radical cyclization, and Pictet–Spengler reactions, into (−)- or (+)-crinane (1 or ent-1, respectively). Variations on these protocols were applied to the total syntheses of (+)- and (−)-11-hydroxyvattitine [(+)- and (−)-3], (+)- and (−)-bulbispermine [(+)- and (−)-4], (+)- and (−)-haemanthamine [(+)- and (−)-5], (+)- and (−)-preTazettine [(+)- and (−)-6], and (+)- and (−)-Tazettine [(+)- and (−)-7] as well as (±)-hamayne [(±)-8] and (±)-apohaemanthamine [(±)-9]. A number of these alkaloids were synthesized for the first time.
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Application of Electrocyclic Ring-Opening and Desymmetrizing Nucleophilic Trappings of meso-6,6-Dibromobicyclo[3.1.0]hexanes to Total Syntheses of Crinine and Haemanthamine Alkaloids
2019Co-Authors: Ping Lan, Martin G. Banwell, Anthony C. WillisAbstract:The thermally induced electrocyclic ring-opening of C2-symmetric (meso) 6,6-dibromobicyclo[3.1.0]hexanes such as 10 in the presence of the chiral, nonracemic 1°-amine 28 afforded a ca. 1:1 mixture of the diastereoisomeric and chromatographically separable 1-amino-2-bromo-2-cyclohexenes 37 (42%) and 38 (45%). Each of these was elaborated over 13 steps, including Suzuki–Miyaura cross-coupling, radical cyclization, and Pictet–Spengler reactions, into (−)- or (+)-crinane (1 or ent-1, respectively). Variations on these protocols were applied to the total syntheses of (+)- and (−)-11-hydroxyvattitine [(+)- and (−)-3], (+)- and (−)-bulbispermine [(+)- and (−)-4], (+)- and (−)-haemanthamine [(+)- and (−)-5], (+)- and (−)-preTazettine [(+)- and (−)-6], and (+)- and (−)-Tazettine [(+)- and (−)-7] as well as (±)-hamayne [(±)-8] and (±)-apohaemanthamine [(±)-9]. A number of these alkaloids were synthesized for the first time
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a total synthesis of 3 o demethylmacronine through rearrangement of a precursor embodying the haemanthidine alkaloid framework
Journal of Organic Chemistry, 2017Co-Authors: Nadia Gao, Martin G. Banwell, Paul D Carr, Anthony C. WillisAbstract:A total synthesis of the racemic modification, (±)-2, of the Tazettine-type alkaloid 3-O-demethylmacronine is described. The key steps are an intramolecular Alder-ene (IMAE) reaction and a lactam-to-lactone rearrangement of tetracycle 13, a compound that embodies the haemanthidine alkaloid framework.
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A Total Synthesis of (±)-3‑O‑Demethylmacronine through Rearrangement of a Precursor Embodying the Haemanthidine Alkaloid Framework
2017Co-Authors: Nadia Gao, Martin G. Banwell, Paul D Carr, Anthony C. WillisAbstract:A total synthesis of the racemic modification, (±)-2, of the Tazettine-type alkaloid 3-O-demethylmacronine is described. The key steps are an intramolecular Alder-ene (IMAE) reaction and a lactam-to-lactone rearrangement of tetracycle 13, a compound that embodies the haemanthidine alkaloid framework
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The Pd-Catalyzed Alder)Ene Reactions of N-Protected and Propargylated 1-Amino-2-aryl-2-cyclohexenes as a New Route to C3a-Arylhexahydroindoles: Towards the Total Synthesis of Tazettine
Australian Journal of Chemistry, 2010Co-Authors: Anna L. Lehmann, Anthony C. Willis, Martin G. BanwellAbstract:A series of N-protected and propargylated 1-amino-2-aryl-2-cyclohexenes (4) has been prepared. Several of these have been shown to undergo an intramolecular Alder–ene reaction in the presence of palladium acetate and the ligand BBEDA to afford C3a-arylhexahydroindoles of the general form 1. Certain of these products may serve as precursors to the alkaloid Tazettine (2).
Evidente A. - One of the best experts on this subject based on the ideXlab platform.
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Alkaloids isolated from indigenous South African Amaryllidaceae: Crinum buphanoides (Welw. ex Baker), Crinum graminicola (I. Verd.), Cyrtanthus mackenii (Hook. f) and Brunsvigia grandiflora (Lindl)
'Elsevier BV', 2018Co-Authors: Masi M., Mubaiwa B., Cimmino A., Van Otterlo W. A. L., Green I. R., Mabank T., Karakoyun C., Evidente A.Abstract:WOS: 000445521800024Screening for alkaloids produced in four indigenous South African Amaryllidaceae plants, namely, Crinum buphanoides Welw. ex Baker, Crinum graminicola I. Verd., Cyrtanthus mackenii Hook. f and Brunsvigia grandiflora Lindl, leads to the isolation of lycorine as the one metabolite produced by all the species studied. C. graminicola produced lycorine in the best yield (2.1 g/kg). Moreover, 1-O-acetyl-and 2-O-acetyl-lycorine, pratorimine, hippadine and Tazettine were isolated from C. buphanoides. Haemanthidine, haemanthamine and criwelline were isolated from C. graminicola, while Tazettine and 11-hydroxyvittatine were produced by C. mackenii. Finally, crinamine and 11-hydroxyvittatine were isolated from B. grandiflora. This is the very first report on the isolation of these alkaloids from the four South African Amaryllidaceae. Furthermore, some interesting chemosystematic evaluations are reported. (c) 2018 SAAB. Published by Elsevier B.V. All rights reserved.South-Africa Ministry of Foreign Affairs Area: South Africa, Medicine and Health [ZA14MO06]; UniNA; Compagnia di San PaoloCompagnia di San Paolo [E62F16001250003]; National Research Foundation of South AfricaNational Research Foundation - South Africa [113322]The work was supported in part by grants from a bilateral project between the Italian and South-Africa Ministry of Foreign Affairs Area: South Africa, Medicine and Health Project number: ZA14MO06, titled: Bioactive metabolites from South-African plants with anticancer activity and in part by the Programme STAR 2017, financially supported by UniNA and Compagnia di San Paolo grant number E62F16001250003. WvO and IRG thank the South African National Research Foundation (NRF) (Incentive and CPRR funding), and Stellenbosch University (Faculty and Departmental support). WvO and IRG acknowledge this work is based in part by support from the National Research Foundation of South Africa (Grant Number 113322). A NEMBA application is being processed. The authors thank Mr. Pierfrancesco Motti and Ms. Nadia Serino for their contributions to this work and thank Dr. Martin Smit (Curator - Stellenbosch University Botanical Garden) for facilitation of live plant specimens
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Alkaloids isolated from indigenous South African Amaryllidaceae: Crinum buphanoides (Welw. ex Baker), Crinum graminicola (I. Verd.), Cyrtanthus mackenii (Hook. f) and Brunsvigia grandiflora (Lindl)
'Elsevier BV', 2018Co-Authors: Masi M., Mubaiwa B., Cimmino A., Van Otterlo W. A. L., Green I. R., Mabank T., Karakoyun Ç., Evidente A.Abstract:Screening for alkaloids produced in four indigenous South African Amaryllidaceae plants, namely, Crinum buphanoides Welw. ex Baker, Crinum graminicola I. Verd., Cyrtanthus mackenii Hook. f and Brunsvigia grandiflora Lindl, leads to the isolation of lycorine as the one metabolite produced by all the species studied. C. graminicola produced lycorine in the best yield (2.1 g/kg). Moreover, 1-O-acetyl- and 2-O-acetyl-lycorine, pratorimine, hippadine and Tazettine were isolated from C. buphanoides. Haemanthidine, haemanthamine and criwelline were isolated fromC. graminicola,while Tazettine and 11-hydroxyvittatinewere produced by C. mackenii. Finally, crinamine and 11-hydroxyvittatine were isolated from B. grandiflora. This is the very first report on the isolation of these alkaloids from the four South African Amaryllidaceae. Furthermore, some interesting chemosystematic evaluations are reported
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Biological evaluation of structurally diverse amaryllidaceae alkaloids and their synthetic derivatives: Discovery of novel leads for anticancer drug design
'Georg Thieme Verlag KG', 2009Co-Authors: Evidente A., Kireev A.s., Jenkins A.r., Romero A.e., Steelant W.f.a., Van Slambrouck S., Kornienko A.Abstract:Twenty-nine Amaryllidaceae alkaloids and their derivatives belonging to the five most common groups, including lycorine, lycorenine, Tazettine, crinine, and narciclasine types, were evaluated for antiproliferative, apoptosis-inducing, and anti-invasive activities in vitro. The antiproliferative properties of each test compound are in agreement with those reported in the literature, while the high potency of amarbellisine is reported for the first time. It was also found that with the exception of ungeremine, amarbellisine, and hippeastrine, the antiproliferative effect of the potent compounds is apoptosis mediated. Thus, apoptosis in Jurkat cells was triggered by narciclasine, narciclasine tetraacetate, C10b-R-hydroxypancratistatin, cis-dihydronarciclasine, trans-dihydronarciclasine, lycorine, 1-O-acetyllycorine, lycorine-2-one, pseudolycorine, and haemanthamine. With the exception of narciclasine, lycorine, and haemanthamine, the apoptosis-inducing properties of these compounds are reported for the first time. The collagen type I invasion assay revealed potent anti-invasive properties associated with N-methyllycorine iodide, hippeastrine, clivimine, buphanamine, and narciclasine tetraacetate, all of which were tested at nontoxic concentrations. The anti-invasive activity of buphanamine is particularly promising because this alkaloid is not toxic to cells even at much higher doses. This work has resulted in the identification of several novel leads for anticancer drug design
Paulo De Andrade, Jean - One of the best experts on this subject based on the ideXlab platform.
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Estudio de la composición alcaloídica de Narcissus broussonetii y de tres especies brasileñas del género Hippeastrum (Amaryllidaceae)
'Edicions de la Universitat de Barcelona', 2014Co-Authors: Paulo De Andrade, JeanAbstract:La familia Amaryllidaceae es conocida por presentar un grupo específico de alcaloides isoquinolínicos, que suelen mostrar un amplio espectro de actividades biológicas. Tres especies del género Hippeastrum, nativo de Brasil, fueron seleccionadas para el estudio en la presente tesis: H. papilio, H. aulicum y H. calyptratum. A su vez, la especie africana Narcissus broussonetii fue elegida para completar el estudio de dicho género, investigación que el grupo de Productos Naturales de esta Universidad viene realizando desde inicio de los años 80. Hippeastrum papilio sintetiza el alcaloide galantamina en cantidades notables además del nuevo compuesto 11beta-hidroxigalantamina. Dicho compuesto es similar al conocido alcaloide habrantina. Utilizando técnicas de RMN se pudo caracterizar correctamente la orientación beta del hidroxilo en el compuesto hallado en H. papilio y, a su vez, se ha confirmado que habrantina es, concretamente, la 11alfa-hidroxigalantamina. Además, 11 beta-hidroxigalantamina presentó una notable actividad inhibidora del enzima aceticolinesterasa (IC50 14.5 ± 0.33 milimicras), aunque inferior a galantamina (1.18 ± 0.07 milimicras). Un total de siete compuestos fueron identificados en esta especie. De Narcissus broussonetii se identificaron 23 compuestos. Se reporta por vez primera los compuestos dinitrogenados obliquina, plicamina y secoplicamina en el género Narcissus. Por tratarse de bases que presentan dos átomos de nitrógeno en su estructura, se planteó estudiar su fragmentación de masas por HPLC-ESI-MS/MS. Se ha demostrado que obliquina y plicamina presentan una manera similar de fragmentarse, diferente a secoplicamina. Mediante derivatización y GC-MS se ha confirmado no solo que tazetina es un artefacto originado en el proceso de extracción a partir del compuesto natural pretazetina, sino que tazetina, como tal, no está presente en la planta. Además se reporta la fragmentación de masas de dichos alcaloides derivatizados a través de técnica de GC-MS/MS. Para finalizar, se identificaron 23 alcaloides de Hippeastrum aulicum y H. calyptratum, siendo 13 de ellos compartidos en ambas especies. Se ha identificado por vez primera el esqueleto tipo crinina en el género Hippeastrum a través de la caracterización completa de los alcaloides aulicina y 3-O-metil-epimacowina utilizando técnicas de CD y difractometría de rayos-X, dato de valor quimiotaxonómico. Además se reportan por vez primera los aislamientos de las bases 7-metoxi-O-metillicorenina y 11-oxohemantamina, aparte de completarse los datos espectroscópicos de los alcaloides nerinina y albomaculina.Plants of the Amaryllidaceae family are a well-known source of tetrahydroisoquinoline alkaloids. These bases have demonstrated a wide-range of biological activities including antiviral, antitumoral, antiparasitic, psychopharmacological, acetylcholinesterase inhibitory, among others. The Brazilian species Hippeastrum papilio, H. aulicum and H. calyptratum along with the African species Narcissus broussonetii were studied in the present Thesis. From H. papilio, an epimer of the previous isolated alkaloid habranthine, 11alpha-hydroxygalanthamine, were isolated and identified using NMR techniques. Furthermore, the 11beta-hydroxygalanthamine showed an important in vitro acetylcholinesterase inhibitory activity (IC50 14.5 ± 0.33 miliM). Additionally, Hippeastrum papilio yielded substantial quantities of galanthamine. Applying the GC-MS technique and an in-home mass fragmentation database, twenty-three alkaloids were identified including the very rare dinitrogenous alkaloids obliquine, plicamine and secoplicamine were identified in Narcissus broussonetii. Using LC-ESI-LTQ-Orbitrap-MS, these dinitrogenous compounds showed a similar fragmentation profile for obliquine and plicamine but different for secoplicamine. PreTazettine, a potent cytotoxic alkaloid, was also isolated from N. broussonetii although its identification by GC-MS was only possible by a BSTFA-derivatization. The silylated crude methanolic extract only showed the presence of preTazettine-TMS, confirming that Tazettine is formed after the alkaloid extraction. As a part of ongoing project in MS of Amaryllidaceae alkaloids, the silylated Tazettine and preTazettine were studied by GC-MS/MS differing in their fragmentation routes. Finally, the EtOAc extract of N. broussonetii showed a notable in vitro activity against Trypanosoma cruzi with an IC50 value of 1.77 µg/ml. Regarding Hippeastrum aulicum and H. calyptratum, the phytochemical procedure guided by GC-MS allowed the identification of two crinine-type alkaloids aulicine and 3-O-methyl-epimacowine, respectively. In addition, a further two new alkaloids 11-oxohaemanthamine (3) and 7-methoxy-O-methyllycorenine (4) were both isolated from H. aulicum. Furthermore, complete NMR spectroscopic data are provided for the homolycorine analogues nerinine (5) and albomaculine (6). Absolute stereochemistry of the 5,10b-ethano bridge in the crinine variants was arrived at by circular dichroism and X-ray crystallographic analysis, affording the first direct evidence for the presence of crinine-type alkaloids in the genus Hippeastrum
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Estudio de la composición alcaloídica de Narcissus broussonetii y de tres especies brasileñas del género Hippeastrum (Amaryllidaceae)
'Edicions de la Universitat de Barcelona', 2014Co-Authors: Paulo De Andrade, JeanAbstract:[spa] La familia Amaryllidaceae es conocida por presentar un grupo específico de alcaloides isoquinolínicos, que suelen mostrar un amplio espectro de actividades biológicas. Tres especies del género Hippeastrum, nativo de Brasil, fueron seleccionadas para el estudio en la presente tesis: H. papilio, H. aulicum y H. calyptratum. A su vez, la especie africana Narcissus broussonetii fue elegida para completar el estudio de dicho género, investigación que el grupo de Productos Naturales de esta Universidad viene realizando desde inicio de los años 80. Hippeastrum papilio sintetiza el alcaloide galantamina en cantidades notables además del nuevo compuesto 11beta-hidroxigalantamina. Dicho compuesto es similar al conocido alcaloide habrantina. Utilizando técnicas de RMN se pudo caracterizar correctamente la orientación beta del hidroxilo en el compuesto hallado en H. papilio y, a su vez, se ha confirmado que habrantina es, concretamente, la 11alfa-hidroxigalantamina. Además, 11 beta-hidroxigalantamina presentó una notable actividad inhibidora del enzima aceticolinesterasa (IC50 14.5 ± 0.33 milimicras), aunque inferior a galantamina (1.18 ± 0.07 milimicras). Un total de siete compuestos fueron identificados en esta especie. De Narcissus broussonetii se identificaron 23 compuestos. Se reporta por vez primera los compuestos dinitrogenados obliquina, plicamina y secoplicamina en el género Narcissus. Por tratarse de bases que presentan dos átomos de nitrógeno en su estructura, se planteó estudiar su fragmentación de masas por HPLC-ESI-MS/MS. Se ha demostrado que obliquina y plicamina presentan una manera similar de fragmentarse, diferente a secoplicamina. Mediante derivatización y GC-MS se ha confirmado no solo que tazetina es un artefacto originado en el proceso de extracción a partir del compuesto natural pretazetina, sino que tazetina, como tal, no está presente en la planta. Además se reporta la fragmentación de masas de dichos alcaloides derivatizados a través de técnica de GC-MS/MS. Para finalizar, se identificaron 23 alcaloides de Hippeastrum aulicum y H. calyptratum, siendo 13 de ellos compartidos en ambas especies. Se ha identificado por vez primera el esqueleto tipo crinina en el género Hippeastrum a través de la caracterización completa de los alcaloides aulicina y 3-O-metil-epimacowina utilizando técnicas de CD y difractometría de rayos-X, dato de valor quimiotaxonómico. Además se reportan por vez primera los aislamientos de las bases 7-metoxi-O-metillicorenina y 11-oxohemantamina, aparte de completarse los datos espectroscópicos de los alcaloides nerinina y albomaculina.[eng] Plants of the Amaryllidaceae family are a well-known source of tetrahydroisoquinoline alkaloids. These bases have demonstrated a wide-range of biological activities including antiviral, antitumoral, antiparasitic, psychopharmacological, acetylcholinesterase inhibitory, among others. The Brazilian species Hippeastrum papilio, H. aulicum and H. calyptratum along with the African species Narcissus broussonetii were studied in the present Thesis. From H. papilio, an epimer of the previous isolated alkaloid habranthine, 11alpha-hydroxygalanthamine, were isolated and identified using NMR techniques. Furthermore, the 11beta-hydroxygalanthamine showed an important in vitro acetylcholinesterase inhibitory activity (IC50 14.5 ± 0.33 miliM). Additionally, Hippeastrum papilio yielded substantial quantities of galanthamine. Applying the GC-MS technique and an in-home mass fragmentation database, twenty-three alkaloids were identified including the very rare dinitrogenous alkaloids obliquine, plicamine and secoplicamine were identified in Narcissus broussonetii. Using LC-ESI-LTQ-Orbitrap-MS, these dinitrogenous compounds showed a similar fragmentation profile for obliquine and plicamine but different for secoplicamine. PreTazettine, a potent cytotoxic alkaloid, was also isolated from N. broussonetii although its identification by GC-MS was only possible by a BSTFA-derivatization. The silylated crude methanolic extract only showed the presence of preTazettine-TMS, confirming that Tazettine is formed after the alkaloid extraction. As a part of ongoing project in MS of Amaryllidaceae alkaloids, the silylated Tazettine and preTazettine were studied by GC-MS/MS differing in their fragmentation routes. Finally, the EtOAc extract of N. broussonetii showed a notable in vitro activity against Trypanosoma cruzi with an IC50 value of 1.77 µg/ml. Regarding Hippeastrum aulicum and H. calyptratum, the phytochemical procedure guided by GC-MS allowed the identification of two crinine-type alkaloids aulicine and 3-O-methyl-epimacowine, respectively. In addition, a further two new alkaloids 11-oxohaemanthamine (3) and 7-methoxy-O-methyllycorenine (4) were both isolated from H. aulicum. Furthermore, complete NMR spectroscopic data are provided for the homolycorine analogues nerinine (5) and albomaculine (6). Absolute stereochemistry of the 5,10b-ethano bridge in the crinine variants was arrived at by circular dichroism and X-ray crystallographic analysis, affording the first direct evidence for the presence of crinine-type alkaloids in the genus Hippeastrum
Martin G. Banwell - One of the best experts on this subject based on the ideXlab platform.
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Application of Electrocyclic Ring-Opening and Desymmetrizing Nucleophilic Trappings of meso-6,6-Dibromobicyclo[3.1.0]hexanes to Total Syntheses of Crinine and Haemanthamine Alkaloids
Journal of Organic Chemistry, 2019Co-Authors: Martin G. Banwell, Anthony C. WillisAbstract:The thermally induced electrocyclic ring-opening of C2-symmetric (meso) 6,6-dibromobicyclo[3.1.0]hexanes such as 10 in the presence of the chiral, nonracemic 1°-amine 28 afforded a ca. 1:1 mixture of the diastereoisomeric and chromatographically separable 1-amino-2-bromo-2-cyclohexenes 37 (42%) and 38 (45%). Each of these was elaborated over 13 steps, including Suzuki–Miyaura cross-coupling, radical cyclization, and Pictet–Spengler reactions, into (−)- or (+)-crinane (1 or ent-1, respectively). Variations on these protocols were applied to the total syntheses of (+)- and (−)-11-hydroxyvattitine [(+)- and (−)-3], (+)- and (−)-bulbispermine [(+)- and (−)-4], (+)- and (−)-haemanthamine [(+)- and (−)-5], (+)- and (−)-preTazettine [(+)- and (−)-6], and (+)- and (−)-Tazettine [(+)- and (−)-7] as well as (±)-hamayne [(±)-8] and (±)-apohaemanthamine [(±)-9]. A number of these alkaloids were synthesized for the first time.
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Application of Electrocyclic Ring-Opening and Desymmetrizing Nucleophilic Trappings of meso-6,6-Dibromobicyclo[3.1.0]hexanes to Total Syntheses of Crinine and Haemanthamine Alkaloids
2019Co-Authors: Ping Lan, Martin G. Banwell, Anthony C. WillisAbstract:The thermally induced electrocyclic ring-opening of C2-symmetric (meso) 6,6-dibromobicyclo[3.1.0]hexanes such as 10 in the presence of the chiral, nonracemic 1°-amine 28 afforded a ca. 1:1 mixture of the diastereoisomeric and chromatographically separable 1-amino-2-bromo-2-cyclohexenes 37 (42%) and 38 (45%). Each of these was elaborated over 13 steps, including Suzuki–Miyaura cross-coupling, radical cyclization, and Pictet–Spengler reactions, into (−)- or (+)-crinane (1 or ent-1, respectively). Variations on these protocols were applied to the total syntheses of (+)- and (−)-11-hydroxyvattitine [(+)- and (−)-3], (+)- and (−)-bulbispermine [(+)- and (−)-4], (+)- and (−)-haemanthamine [(+)- and (−)-5], (+)- and (−)-preTazettine [(+)- and (−)-6], and (+)- and (−)-Tazettine [(+)- and (−)-7] as well as (±)-hamayne [(±)-8] and (±)-apohaemanthamine [(±)-9]. A number of these alkaloids were synthesized for the first time
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a total synthesis of 3 o demethylmacronine through rearrangement of a precursor embodying the haemanthidine alkaloid framework
Journal of Organic Chemistry, 2017Co-Authors: Nadia Gao, Martin G. Banwell, Paul D Carr, Anthony C. WillisAbstract:A total synthesis of the racemic modification, (±)-2, of the Tazettine-type alkaloid 3-O-demethylmacronine is described. The key steps are an intramolecular Alder-ene (IMAE) reaction and a lactam-to-lactone rearrangement of tetracycle 13, a compound that embodies the haemanthidine alkaloid framework.
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A Total Synthesis of (±)-3‑O‑Demethylmacronine through Rearrangement of a Precursor Embodying the Haemanthidine Alkaloid Framework
2017Co-Authors: Nadia Gao, Martin G. Banwell, Paul D Carr, Anthony C. WillisAbstract:A total synthesis of the racemic modification, (±)-2, of the Tazettine-type alkaloid 3-O-demethylmacronine is described. The key steps are an intramolecular Alder-ene (IMAE) reaction and a lactam-to-lactone rearrangement of tetracycle 13, a compound that embodies the haemanthidine alkaloid framework
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The Pd-Catalyzed Alder)Ene Reactions of N-Protected and Propargylated 1-Amino-2-aryl-2-cyclohexenes as a New Route to C3a-Arylhexahydroindoles: Towards the Total Synthesis of Tazettine
Australian Journal of Chemistry, 2010Co-Authors: Anna L. Lehmann, Anthony C. Willis, Martin G. BanwellAbstract:A series of N-protected and propargylated 1-amino-2-aryl-2-cyclohexenes (4) has been prepared. Several of these have been shown to undergo an intramolecular Alder–ene reaction in the presence of palladium acetate and the ligand BBEDA to afford C3a-arylhexahydroindoles of the general form 1. Certain of these products may serve as precursors to the alkaloid Tazettine (2).
Jaume Bastida - One of the best experts on this subject based on the ideXlab platform.
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alkaloid profile in pyrolirion albicans herb amaryllidaceae a peruvian endemic species
South African Journal of Botany, 2021Co-Authors: Hibert Huaylla, Laura Torrasclaveria, Olimpia Llalla, Jaume BastidaAbstract:Abstract The Amaryllidaceae family is widely distributed in different regions of the neotropics and temperate areas of the world. Species of the subfamily Amaryllidoideae are unique in producing the alkaloid galanthamine, which inhibits the action of acetylcholinesterase and is used for the treatment of Alzheimer's disease. In Peru, 15 genera and 68 species belonging to the Amaryllidoideae have been reported in different types of forest, ranging from wet montane to dry, as well as the sandy biomes of the Pacific coastal region, with the greatest diversity in the south. In the tribe Eustephieae, the Andean genus Pyrolirion Herb has eight species, six of which are endemic to Peru. In this work, the leaves and bulbs of Pyrolirion albicans were analyzed for their alkaloid content for the first time, using gas chromatography (GC) coupled to mass spectrometry (MS). The alkaloids determined in the leaves were galanthamine, chlidanthine, Tazettine and lycorine and those in the bulbs were galanthamine, N-demethylgalanthamine, vittatine/crinine, montanine, pancracine, sternbergine, lycorine and hippeastrine. Owing to their important bioactive properties, the high quantity of montanine and galanthamine determined in the bulbs is of particular interest.
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analysis of bioactive amaryllidaceae alkaloid profiles in lycoris species by gc ms
Natural Product Communications, 2014Co-Authors: Ying Guo, Francesc Viladomat, Carles Codina, Jean Paulo De Andrade, Natalia B Pigni, Yuhong Zheng, Laura Torrasclaveria, Jaume BastidaAbstract:The genus Lycoris, a group of Amaryllidaceae plants distributed in temperate regions of Eastern Asia, is already known for containing representative alkaloids typical of this botanical family with a wide range of biological activities (for example, lycorine and galanthamine). In the present work, the alkaloid profiles of nine species, L. albiflora, L. aurea, L. chinensis, L. haywardii, L. incarnata, L. longituba, L. radiata, L. sprengeri, and L. squamigera, and one variety (L. radiata var. pumila) have been evaluated by GC-MS. Structures belonging to the lycorine-, homolycorine-, haemanthamine-, narciclasine-, Tazettine-, montanine- and galanthamine-series were identified and quantified, with galanthamine- and lycorine-type alkaloids predominating and usually showing a high relative abundance in comparison with other alkaloids of the extracts. Interestingly, L. longituba revealed itself to be a potential commercial source of bioactive alkaloids. In general terms, our results are consistent with the alkaloid profiles reported in the literature for previously studied species.
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alkaloids from hippeastrum morelianum lem amaryllidaceae
Magnetic Resonance in Chemistry, 2011Co-Authors: Raquel Brandt Giordani, Jaume Bastida, Jean Paulo De Andrade, Strahil Berkov, Julie Henriette Antoinette Dutilh, Amelia T Henriques, Hugo Verli, Jose Angelo S ZuanazziAbstract:The Amaryllidaceae family has proven to be a rich source of active molecules. As part of an ongoing project, we report a phytochemical study of Hippeastrum morelianum (Amaryllidaceae), from which we have isolated two homolycorine-type alkaloids, the new 2α,7-dimethoxyhomolycorine (1) and the poorly described candimine (2), as well as six known alkaloids: Tazettine, preTazettine, 3-epimacronine, haemanthamine, hamayne and trisphaeridine. For reference purposes, the NMR of the isolated compounds was unequivocally described, based on 2D NMR measurements including (1)H-(1)H COSY, (1)H-(1)H NOESY, HSQC and HMBC.
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Alkaloid diversity in Galanthus elwesii and Galanthus nivalis.
Chemistry & Biodiversity, 2011Co-Authors: Jaume Bastida, Francesc Viladomat, Borjana Sidjimova, Carles CodinaAbstract:Seventy alkaloids of galanthamine, lycorine, homolycorine, Tazettine, haemanthamine, narciclasine, and tyramine types were detected by GC/MS in 25 Galanthus elwesii and seven Galanthus nivalis populations, collected from different locations in Bulgaria. Intraspecies diversity in the alkaloid profiles regarding the main alkaloid types (chemotypes) was observed. Tyramine-type protoalkaloids (namely, hordenine and its derivatives) were dominant in 19 populations of G. elwesii. In other populations of G. elwesii, the plants accumulated mainly homolycorine-, lycorine-, and galanthamine-type alkaloids. The alkaloid profiles of G. nivalis were dominated by narciclasine-, galanthamine-, lycorine-, haemanthamine-, or Tazettine-type compounds. Geographical distribution of chemotypes indicated a relationship between populations, since adjacent populations often displayed similar alkaloid profiles. The results from year-to-year sampling and transplantation experiments imply genetic determination of alkaloid synthesis in the two studied species of Galanthus.
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Three new alkaloids from Galanthus nivalis and Galanthus elwesii.
Planta Medica, 2009Co-Authors: María Cuadrado, Francesc Viladomat, Edison Osorio, Jaume BastidaAbstract:Phytochemical studies on Galanthus species resulted in the iso- lation of three new compounds: 3,3'-O-(3',3''-dihydroxybuta- noyl)hamayne and 11,3'-O-(3',3''-dihydroxybutanoyl)hamayne from G. nivalis and 2-O-(3'-hydroxybutanoyl)lycorine from G. elwesii. Additionally, 3,11-O-(3',3''-dihydroxybutanoyl)hamayne, 3,11,3'-O-(3',3'',3'''-trihydroxybutanoyl)hamayne, 8-O-demeth- ylvasconine, Tazettine, epimacronine, and ismine from G. nivalis; 2-O-(3'-acetoxybutanoyl)lycorine and incartine from G. elwesii; and hamayne, 11-O-(3'-hydroxybutanoyl)hamayne and lycorine from both species were isolated. Their structures were deter- mined by EI‑MS, HR‑MS, CD, and 1D and 2DNMR (COSY, NOESY, HMQC, and HMBC) experiments.
