- Synthesis of novel 1,2,3-triazole derivatives of isocoumarins and 3,4-dihydroisocoumarin with potential antiplasmodial activity in vitro
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Background: Malaria greatly affects the world health, having caused more than 228 million cases only in 2018. The emergence of drug resistance is one of the main problems in its treatment, dem-onstrating the need for the development of new antimalarial drugs. Objective: Synthesis and in vitro antiplasmodial evaluation of triazole compounds derived from isocou-marins and a 3,4-dihydroisocoumarin. Methods: The compounds were synthesized in 4 to 6-step reactions with the formation of the triazole ring via the Copper(I)-catalyzed 1,3-dipolar cycloaddition between isocoumarin or 3,4-dihydroisocoumarin azides and terminal alkynes. This key reaction provided compounds with an un-precedented connection of isocoumarin or 3,4-dihydroisocoumarin and the 1,2,3-triazole ring. The products were tested for their antiplasmodial activity against a Plasmodium falciparum chloroquine resistant and sensitive strains (W2 and 3D7, respectively). Results: Thirty-one substances were efficiently obtained by the proposed routes with an overall yield of 25-53%. The active substances in the antiplasmodial test displayed IC50 values ranging from 0.68-2.89 μM and 0.85-2.07 μM against W2 and 3D7 strains, respectively. Conclusion: This study demonstrated the great potential of isocoumarin or 3,4-dihydroisocoumarin derivatives because practically all the tested substances were active against Plasmodium falciparum.
- Alves, Rosemeire Brondi,Pinto, Ana Claudia de Souza,Santos, Lucas da Silva,Varotti, Fernando de Pilla,da Fonseca, Amanda Luisa,de Carvalho, Matheus Fillipe Langanke,de Freitas, Rossimiriam Pereira,Lopes, Julio César Dias
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p. 820 - 833
(2021/10/21)
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- 6,7-DIHYDRO-5H-PYRIDO[2,3-C]PYRIDAZINE DERIVATIVES AND RELATED COMPOUNDS AS BCL-XL PROTEIN INHIBITORS AND PRO-APOPTOTIC AGENTS FOR TREATING CANCER
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The present invention discloses 6,7-dihydro-5H-pyrido[2,3- c]pyridazine, 1,2,3,4-tetrahydroquinoline, 1H-indole, 3,4- dihydro-2H-1,4-benzoxazine, 1H-pyrrolo[2,3-b]pyridin-1-yl, 7H- pyrrolo[2,3-c]pyridazine, 5H,6H,7H,8H,9H-pyridazino[3,4-b]azepine derivatives and related compounds of formula (I) as Bcl-xL protein inhibitors for use as pro-apoptotic agents for treating cancer, autoimmune diseases or immune system diseases. Formula (I). The description discloses the preparation of exemplary compounds (e.g. pages 113 to 354 examples 1 to 221) as well as pharmacological studies with relevant data (e.g. pages 355 to 367; examples A to E; tables 1 to 5). Exemplary compounds are e.g. 2-{6-[(1,3-benzothiazol-2-yl) amino]-1,2,3,4-tetrahydroquinolin-1-yl}-1,3-thiazole-4-carboxylic acid (example 1) or e.g. 3-{1-[(adamantan-1-yl)methyl]-5- methyl-1H-pyrazol-4-yl}-6-{3-[(1,3-benzothiazol-2-yl)amino]-4- methyl-5H,6H,7H,8H-pyrido[2,3-c]pyridazin-8-yl]pyridine-2-carboxylic acid (example 24).
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Page/Page column 51
(2021/02/05)
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- 3,6-DIAMINO-PYRIDAZIN-3-YL DERIVATIVES, PHARMACEUTICAL COMPOSITIONS CONTAINING THEM AND THEIR USES AS PRO-APOPTOTIC AGENTS
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Compounds of formula (I) wherein Het1, Het2, R1, R2 and R3 are as defined in the description. Medicaments.
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Page/Page column 143-144
(2021/02/05)
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- Fluorohydration of alkynes via I(I)/I(III) catalysis
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Substrate specificity is ubiquitous in biological catalysis, but less pervasive in the realm of small-molecule catalysis. Herein, we disclose an intriguing example of substrate specificity that was observed whilst exploring catalysis-based routes to generate α-fluoroketones from terminal and internal alkynes under the auspices of I(I)/I(III) catalysis. Utilising p-TolI as an inexpensive organocatalyst with Selectfluor and amine/HF mixtures, the formation of protected α-fluoroketones from simple alkynes was realised. Whilst the transient p-TolIF2 species generated in situ productively engaged with pentynyl benzoate scaffolds to generate the desired α-fluoroketone motif, augmentation or contraction of the linker suppressed catalysis. The prerequisite for this substructure was established by molecular editing and was complemented with a physical organic investigation of possible determinants.
- Daniliuc, Constantin G.,Gilmour, Ryan,Neufeld, Jessica
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supporting information
p. 1627 - 1635
(2020/09/11)
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- Fluorine in pheromones: Synthesis of fluorinated 12-dodecanolides as emerald ash borer pheromone mimetics
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A series of five 12-dodecanolides have been synthesised containing CF2 groups at C5, C6, C7, C8 and in one case, a double substitution at C5 & C8, as a strategy to bias the conformational space accessed by these macrocycles, and to assess if th
- Zhang, Qingzhi,Teschers, Charlotte S.,Callejo, Ricardo,Yang, Mingyan,Wang, Mingan,Silk, Peter J.,Ryall, Krista,Roscoe, Lucas E.,Cordes, David B.,Slawin, Alexandra M.Z.,O'Hagan, David
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supporting information
p. 2917 - 2922
(2019/04/30)
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- Gold(III)-Catalyzed Regioselective Oxidation/Cycloisomerization of Diynes: An Approach to Fused Furan Derivatives
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The first gold(III)-catalyzed regioselective oxidation/cycloisomerization of diynes 1 with pyridine N-oxide as the oxidant was developed, providing a range of synthetically valuable and useful fused furan derivatives 3 in moderate to good yields. Control experiments and the confirmation structure of minor products 5 suggest that this chemistry was a concerted gold(III)-catalyzed oxidation/SN2′-type addition/cyclization process via a β-gold vinyloxypyridinium intermediate and a putative vinyl cation intermediate.
- Li, Jian,Xing, Hong-Wen,Yang, Fang,Chen, Zi-Sheng,Ji, Kegong
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supporting information
p. 4622 - 4626
(2018/08/07)
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- Pyrrolidine compounds, salts thereof, applications of compounds or salts thereof in nuclear magnetic probes and medicines, reagent, and medicine
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The invention provides pyrrolidine compounds, salts thereof, applications of the compounds or the salts thereof in nuclear magnetic probes and medicines, a reagent, and a medicine. The benzamide methylpyrrolidine compounds have a chemical structure represented by general formula (I); and in the formula (I), R is selected from a methyl group, an ethyl group, a methoxy group, an ethoxy group and halogen, R is selected from a methyl group, an ethyl group, a methoxy group, an ethoxy group and halogen, R is selected from C1-5 alkyl groups and H, X is selected from C1-10 alkylene groups or is deleted, X is selected from -(CH2CH2O)n- (n is 1-5) or is deleted, X is selected from C1-5 alkyl groups, X is selected from oxygen, sulfur and a methylene group, and Ln is selected from Gd and Eu. The compounds have a gadolinium and europium chelating structure formed by combining with a dopamine D2 receptor and depending on intramolecular chelating groups, and specifically enhance the contrast of dopamine D2 receptor expression tissues on images in magnetic resonance imaging.
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Paragraph 0093; 0094; 0095
(2017/08/27)
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- Vanadium-Catalyzed Oxidative Debenzylation of O-Benzyl Ethers at ppm Level
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An advantageous methodology for the oxidative debenzylation of ethers has been developed. Very low amounts of a catalyst system based on vanadyl acetylacetonate and a triazole type pincer ligand allow the selective oxidative cleavage of a number of O-benzyl ethers in the presence of oxygen as the sole oxidant. The methodology tolerates a number of functional groups such as halo-, alkoxy-, or trifluoromethylarenes, alkyne, alkene, ether, and acetal units. Large-scale deprotections can be also carried out by the optimized procedure, which is amenable to enantioenriched reactants as well. (Figure presented.).
- Urgoitia, Garazi,SanMartin, Raul,Herrero, María Teresa,Domínguez, Esther
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supporting information
p. 3307 - 3312
(2016/10/21)
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- [3 + 2]-Cycloadditions of Azomethine Imines and Ynolates
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A novel [3 + 2]-cycloaddition between azomethine imines and lithium ynolates is described to synthesize bicyclic pyrazolidinones. These bicyclic pyrazolidinones are versatile intermediates to form β-amino acids and monocyclic pyrazolidinones. High diaster
- Winterton, Sarah E.,Ready, Joseph M.
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supporting information
p. 2608 - 2611
(2016/06/15)
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- Enzyme kinetics and inhibition of histone acetyltransferase KAT8
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Lysine acetyltransferase 8 (KAT8) is a histone acetyltransferase (HAT) responsible for acetylating lysine 16 on histone H4 (H4K16) and plays a role in cell cycle progression as well as acetylation of the tumor suppressor protein p53. Further studies on its biological function and drug discovery initiatives will benefit from the development of small molecule inhibitors for this enzyme. As a first step towards this aim we investigated the enzyme kinetics of this bi-substrate enzyme. The kinetic experiments indicate a ping-pong mechanism in which the enzyme binds Ac-CoA first, followed by binding of the histone substrate. This mechanism is supported by affinity measurements of both substrates using isothermal titration calorimetry (ITC). Using this information, the KAT8 inhibition of a focused compound collection around the non-selective HAT inhibitor anacardic acid has been investigated. Kinetic studies with anacardic acid were performed, based on which a model for the catalytic activity of KAT8 and the inhibitory action of anacardic acid (AA) was proposed. This enabled the calculation of the inhibition constant Ki of anacardic acid derivatives using an adaptation of the Cheng-Prusoff equation. The results described in this study give insight into the catalytic mechanism of KAT8 and present the first well-characterized small-molecule inhibitors for this HAT.
- Wapenaar, Hannah,Van Der Wouden, Petra E.,Groves, Matthew R.,Rotili, Dante,Mai, Antonello,Dekker, Frank J.
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supporting information
p. 289 - 296
(2015/11/09)
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- Z-Selective Copper(I)-Catalyzed Alkyne Semihydrogenation with Tethered Cu-Alkoxide Complexes
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A highly stereoselective alkyne semihydrogenation with copper(I) complexes is reported. Copper-N-heterocyclic carbene complex catalysts, bearing an intramolecular Cu-O bond, allow for the direct transfer of both hydrogen atoms from dihydrogen to the alkyn
- Pape, Felix,Thiel, Niklas O.,Teichert, Johannes F.
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supporting information
p. 15934 - 15938
(2015/11/03)
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- A palladium nanoparticle-nanomicelle combination for the stereo-selective semihydrogenation of alkynes in water at room temperature
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The addition of NaBH4 to Pd(OAc) 2 in water containing nanomicelles leads to the generation of H2 and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affords Z-alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors.
- Slack, Eric D.,Gabriel, Christopher M.,Lipshutz, Bruce H.
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supporting information
p. 14051 - 14054
(2015/02/19)
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- Copper-catalyzed vinylsilane allylation
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Soft reaction conditions, particularly important in total synthesis, have dragged many researchers into the field of silylated organic compounds. Hereby, we describe a new copper-catalyzed vinylsilane transformation. Various vinylsilanes were allylated by using a copper(I) salt, and this led to the formation of polysubstituted 1,4-dienes bearing sensitive moieties such as halogens, ketones, and aldehydes. Hereby is described a new copper-catalyzed vinylsilane transformation. Various vinylsilanes were allylated by using copper(I) salts, and this led to the formation of polysubstituted 1,4-dienes bearing sensitive moieties such as halogens, ketones, and aldehydes. TBAT = tetrabutylammonium difluorotriphenylsilicate. Copyright
- Cornelissen, Loic,Vercruysse, Sebastien,Sanhadji, Ayoub,Riant, Olivier
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supporting information
p. 35 - 38
(2014/01/06)
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- CuI/Pd0 cooperative dual catalysis: Tunable stereoselective construction of tetra-substituted alkenes
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This paper describes a tunable and stereoselective dual catalytic system that uses copper and palladium reagents. This cooperative silylcupration and palladium-catalyzed allylation readily affords trisubstituted alkenylsilanes. Fine-tuning the reaction conditions allows selective access to one stereoisomer over the other. This new methodology tolerates different substituents on both coupling partners with high levels of stereoselectivity. The one-pot reaction involving a CuI/Pd0 cooperative dual catalyst directly addresses the need to develop more time-efficient and less-wasteful synthetic pathways.
- Vercruysse, Sebastien,Cornelissen, Loic,Nahra, Fady,Collard, Laurent,Riant, Olivier
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supporting information
p. 1834 - 1838
(2014/03/21)
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- Design and synthesis of a class of twin-chain amphiphiles for self-assembled monolayer-based electrochemical biosensor applications
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A new class of twin-chain hydroxyalkylthiols (mercaptoalkanols) is described that features a nearly constant cross section and the potential for modification at one or both termini. These compounds are regioselectively available through Pd-mediated coupli
- Fisher, Thomas J.,Canete, Socrates Jose P.,Lai, Rebecca Y.,Dussault, Patrick H.
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p. 3263 - 3270
(2013/07/05)
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- A concise synthesis of the ab-ring fragment of (-)-gambierol
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We describe herein a concise synthesis of the AB-ring fragment of gambierol, wherein silver(I) trifluoromethanesulfonate-catalyzed 6-endo cyclization of a hydroxy ynone was exploited for the formation of the A-ring.
- Fuwa, Haruhiko,Hirota, Kazuaki,Sasaki, Makoto
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p. 127 - 132
(2013/08/23)
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- SELF-ASSEMBLED MONOLAYERS AND METHODS FOR USING THE SAME IN BIOSENSING APPLICATIONS
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Cross-linked amphiphile constructs that form self-assembled monolayers (SAMs) on metal surfaces such as gold surfaces are disclosed. These new SAMs generate well packed and highly oriented monolayer films on gold surfaces. A method for using the SAMs in t
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Page/Page column 13
(2013/02/27)
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- Benzylation of hydroxy groups with tertiary amine as a base
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The benzylation of hydroxy groups in the presence of tertiary amines is described. A mixture of an alcohol and a benzyl halide afforded the corresponding benzyl ether in good to excellent yields in the presence of diisopropylethylamine. The importance of solventless conditions was observed. The reaction showed high tolerance to many functional groups including benzoate, even at a reaction temperature of 150 °C. Sodium iodide was found to be an efficient catalyst to accelerate the reaction.
- Gathirwa, Jeremiah W.,Maki, Toshihide
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experimental part
p. 370 - 375
(2012/01/14)
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- Triflic acid catalyzed reductive coupling reactions of carbonyl compounds with O-, S-, and N-nucleophiles
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Highly efficient metal-free reductive coupling reactions of aldehydes and ketones with a range of nucleophiles in the presence of triflic acid (1-5 mol %) as the catalyst are presented. The reactions can be performed at ambient temperature without exclusion of moisture or air. A range of symmetrical and unsymmetrical ethers were obtained by this method in high yields and short reaction times. For the first time, the influence of additional functionalization has been studied. Furthermore, the formation of thioethers from ketones (by addition of unmodified thiols) and of sulfonamides from either aldehydes or ketones has been achieved under catalytic conditions.
- Gellert, Beate A.,Kahlcke, Nils,Feurer, Markus,Roth, Stefanie
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supporting information; experimental part
p. 12203 - 12209
(2011/11/07)
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- Synthesis of (-)-okilactomycin by a prins-type fragment-assembly strategy
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All things converge: A highly convergent synthesis of (-)-okilactomycin utilizes a Prins-type Maitland-Japp cyclization for the fragment assembly of two complex intermediates (see scheme). The synthesis also employs a highly diastereoselective Lewis acid promoted Diels-Alder reaction and an olefin ring-closing metathesis to close a strained 11-membered macrocycle.
- Tenenbaum, Jason M.,Morris, William J.,Custar, Daniel W.,Scheidt, Karl A.
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supporting information; experimental part
p. 5892 - 5895
(2011/08/04)
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- Stereoselective synthesis of disubstituted butadienes via copper-mediated coupling of alkenyl silanes
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A strategy is described for the stereoselective synthesis of substituted (E)-, (Z)-, and -disubstituted butadienes from terminal alkynes by the copper-mediated coupling of geometrically-defined alkenyl silanes. Proof-of-concept results that demonstrate the feasibility of this approach are presented. Georg Thieme Verlag Stuttgart · New York.
- Blackwell, David T.,Galloway, Warren R. J. D.,Spring, David R.
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supporting information; experimental part
p. 2140 - 2144
(2011/11/06)
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- Synthesis of ACAT inhibitors through substitution using allylic picolinate and copper reagent
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Amide of an octanoic acid possessing an aryl group at C3 position is a highly potent ACAT inhibitor. In this paper, we describe a synthetic access to this class of compounds as optically active forms. The key reaction is substitution of the allylic picoli
- Kobayashi, Yuichi,Lalitnorasate, Paveena,Kaneko, Yuki,Kiyotsuka, Yohei,Endo, Yoshiki
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scheme or table
p. 6018 - 6021
(2010/11/21)
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- Facile deprotection of bulky (trialkylsilyl)acetylenes with silver fluoride
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An efficient and mild method is developed for the deprotection of bulky (trialkylsilyl)acetylenes. Treatment of 1-(triisopropylsilyl) acetylenes with silver fluoride, followed by hydrolysis of the intermediate silver acetylide with organic or inorganic ac
- Kim, Sanghee,Kim, Bogyeong,In, Jinkyung
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experimental part
p. 1963 - 1968
(2009/12/27)
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- Total synthesis of (+)-batzelladine A and (-)-batzelladine D via [4 + 2]-annulation of vinyl carbodiimides with N-alkyl imines
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A diastereoselective [4 + 2]-annulation of vinyl carbodiimides with chiral N-alkyl imines has been developed to access the stereochemically rich polycyclic guanidine cores of the batzelladine alkaloids. Application of this strategy, together with additional key steps such as long-range directed hydrogenation and diastereoselective intramolecular iodo-amination, led to highly convergent total syntheses of (-)-batzelladine D and (+)-batzelladine A with excellent stereocontrol.
- Arnold, Michael A.,Day, Kenneth A.,Duron, Sergio G.,Gin, David Y.
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p. 13255 - 13260
(2008/03/11)
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- First synthesis and determination of the absolute stereochemistry of iso-cladospolide-B and cladospolides-B and C
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The syntheses of iso-cladospolide-B, cladospolide-B and cladospolide-C are reported with 4S,5S,11S-configuration. Of the three stereogenic centres, the C-4/C-5 vic-diol was created by Evans aldol condensation, while the C-11 stereocentre was created by Ja
- Sharma,Laxmi Reddy,Janardhan Reddy
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p. 6537 - 6540
(2007/10/03)
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- A chemoselective deprotection of trimethylsilyl acetylenes catalyzed by silver salts
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Trimethylsilyl acetylenes can be selectively deprotected in the presence of a catalytic amount of silver salts. AgNO3 and AgOTf proved to be the most effective catalyst in a mixture of methanol, water and dichloromethane. Other functional groups, and especially silyl ethers, are not affected in these conditions.
- Orsini, Alban,Vitérisi, Aurélien,Bodlenner, Anne,Weibel, Jean-Marc,Pale, Patrick
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p. 2259 - 2262
(2007/10/03)
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- 8beta-Vinyl-11beta-(omega-substituted)alkyl-estra-1,3,5(10)-trienes
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This invention relates to 8β-vinyl-11β-(ω-substituted)alkyl-estra-1,3,5(10)-trienes of general formula I with ERβ-antagonistic activity, process for their production, their intermediate products, pharmaceutical preparations that contain the compounds acco
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Page/Page column 16
(2010/02/11)
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- 8Γ(B)-VINYL-11Γ(B)-(Γ(V)-SUBSTITUTED)ALKYL-ESTRA-1,3,5(10)-TRIENES
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The invention relates to 8β-vinyl-11β-(ω-substituted)alkyl-estra-1,3,5(10)-trienes of general formula (I), which have ERβ-antagonistic activity, methods for the production thereof, the intermediate products thereof, pharmaceutical preparations containing the inventive compounds, and the use thereof for producing medicaments. The novel compounds can be used for contraceptive purposes in men and women without influencing other estrogen-sensitive organs such as the uterus or the liver and while also being suitable for the treatment of benign or malignant proliferous ovarian diseases, such as ovarian carcinoma and granulosa cell tumors.
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Page/Page column 35
(2010/02/09)
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- Coupling of alkynylTMS derivatives with vinylic iodides. An efficient route to 1,3-enynes and dienes
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matrix presented CuCl-promoted coupling of alkynylTMS derivatives with vinyl iodides leads to 1,3-enynes in high yield. Enynes prepared from homopropargylic alcohols undergo intramolecular hydrosilylation and subsequent silyl cleavage with TBAF to afford
- Marshall, James A.,Chobanian, Harry R.,Yanik, Mathew M.
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p. 4107 - 4110
(2007/10/03)
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- Synthesis and structure determination of iso-cladospolide B
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iso-Cladospolide B 1 was previously characterized from the fungal isolate I96S215 obtained from a marine sponge collected in Indonesia. However, neither the relative nor the absolute configurations were reported. We describe in this letter a synthetic pathway which allowed us to prepare 1 and attribute the absolute configurations of the three stereogenic centers.
- Franck, Xavier,Vaz Araujo, Maria E.,Jullian, Jean-Christophe,Hocquemiller, Reynald,Figadère, Bruno
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p. 2801 - 2803
(2007/10/03)
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- Acid-catalyzed cyclization of vinylsilanes bearing a hydroxy group: A new method for stereoselective synthesis of disubstituted tetrahydrofurans
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In the presence of a catalytic amount of TsOH or TiCl4, (Z)-5-silyl-4-penten-1-ols ((Z)-1) are smoothly cyclized to 2-silylmethyl-substituted tetrahydrofurans. This cyclization is applicable to the construction of a tetrahydropyran ring. The silyl group and the geometry of the C-C double bond strongly influence the cychzation rate. TBDMS and benzyldimethylsilyl groups considerably accelerate the cyclization in comparison with a dimethylphenylsilyl group, and (E)-vinylsilanes show much lower reactivity than the corresponding (Z)-isomers. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes 17, 19, and 21, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted tetrahydrofurans, respectively, with moderate to high stereoselectivity. The silyl group of some cychzed products can be easily converted into a hydroxy group with stereochemical retention.
- Miura,Okajima,Hondo,Nakagawa,Takahashi,Hosomi
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p. 11348 - 11357
(2007/10/03)
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- A convenient new route to piperidines, pyrrolizidines, indolizidines, and quinolizidines by cyclization of acetylenic sulfones with β- and γ-chloroamines. Enantioselective total synthesis of indolizidines (-)-167B, (-)-209D, (-)-209B, and (-)-207A
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The methyl esters of (L)-phenylalanine and (L)-methionine underwent conjugate additions via their free amino groups to 1-(p-toluenesulfonyl)hexyne, followed by intramolecular acylation of the corresponding enamide anions and tautomerization to afford 2-benzyl-5-n-butyl-3-hydroxy-4-(p-toluenesulfonyl)pyrrole and 5-n-butyl-3-hydroxy-2-(2-methylthioethyl)-4-(p-toluenesulfonyl)pyrrole, respectively. The conjugate additions of a series of acyclic and cyclic secondary β- and γ-chloroamines to acetylenic sulfones proceeded similarly under mild conditions. The resulting adducts were deprotonated with LDA in THF at -78 °C, and the resulting sulfone-stabilized carbanions underwent intramolecular alkylation to afford cyclic enamine sulfones. Thus, acyclic γ-chloroalkylbenzylamines afforded the corresponding 2- or 2,6-disubstituted piperidines, while 2-(chloromethyl)-pyrrolidines, 2-(2-chloroethyl)pyrrolidines, 2-(chloromethyl)piperidines, and 2-(2-chloroethyl)-piperidines produced the corresponding 3-substituted pyrrolizidines, 5- or 3-substituted indolizidines, and 4-substituted quinolizidines, respectively. 8-Methyl-5-substituted indolizidines were also prepared from the appropriate methyl-substituted chloroamine precursor. Enantioselective syntheses were achieved by employing chiral chloroamines derived from amino acids or other enantiopure precursors. Further transformations of several of the products provided concise syntheses of four dendrobatid alkaloids. Thus, reduction of (8aS)-5-n-propyl-6-(p-toluenesulfonyl)-Δ-indolizidine with sodium cyanoborohydride in trifluoroacetic acid, followed by reductive desulfonylation, afforded (-)-indolizidine 167B. The corresponding 5-n-hexyl derivative similarly produced (-)-indolizidine 209D, while (-)-(8R,8aS)-8-methyl-5-n-pentyl-6-(p-toluenesulfonyl)-Δ5,6-indolizidine furnished (-)-indolizidine 209B. Finally, the similar reduction and debenzylation of (-)-(8R,8aS)-5-(2-benzyloxyethyl)-8-methyl-6-(p-toluenesulfonyl)-Δ-indolizid ine produced the corresponding 5-hydroxyethyl indolizidine. This was subjected to chlorination of the alcohol group with thionyl chloride and substitution with a higher order allyl cuprate reagent to afford (-)-indolizidine 207A.
- Back, Thomas G.,Nakajima, Katsumasa
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p. 4543 - 4552
(2007/10/03)
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- Novel decomplexation method for alkyne-Co2(CO)6 complexes
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A novel and general decomplexation method for alkyne-Co2(CO)6 complexes has been established, which treats the complexes with ethylenediamine in THF.
- Sugihara, Takumichi,Ban, Hitoshi,Yamaguchi, Masahiko
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p. 163 - 166
(2007/10/03)
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- The Synthesis of Cembranolide Precursors via Addition of Allylstannanes to Conjugated Aldehydes
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The Lewis acid promoted addition of functionalized allylstannanes A9, C10, and C11 to a variety of conjugated aldehydes was examined as a possible route to acyclic precursors of macrocyclic diterpenoids.Additions to crotonaldehyde proceeded as expected, g
- Marshall, James A.,DeHoff, Bradley S.
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p. 863 - 872
(2007/10/02)
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