- CpRu/Br?nsted Acid-Catalyzed Enantioselective Dehydrative Cyclization of Pyrroles N-Tethered with Allylic Alcohols
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A cationic CpRu/halogen/Br?nsted acid hybrid catalyst (R ?cat) with the axially chiral Cl-Naph-PyCOOH ligand (naph = naphthyl, py = pyridine) is highly efficient for dehydrative cyclization of pyrroles to construct 1,2-fused-2-allylated pyrroles that, so far, have not been achieved. The mechanistic study has implied that hydrogen and halogen bonds play a key role for facilitating the R,SRu-catalyzed reaction pathway via a σ-allyl intermediate and that the diastereomeric R,RRu ?cat slowly gives the minor enantiomer via a π-allyl intermediate.
- Iwase, Shoutaro,Kitamura, Masato,Suzuki, Yusuke,Tanaka, Shinji
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Read Online
- DNA-binding studies of a tetraalkyl-substituted porphyrin and the mutually adaptive distortion principle
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This investigation explores DNA-binding interactions of various forms of an alkyl-substituted cationic porphyrin, H2TC3 (5,10,15,20-tetra[3-(3′-methylimidazolium-1′-yl)]-porphyrin). The motivating idea is that incorporating alkyl rather than aryl substituents in the meso positions will enhance the prospects for intercalative as well as external binding to DNA hosts. The ligands may also be applicable for photodynamic and/or anticancer therapy. Methods employed include absorbance, circular dichroism, and emission spectroscopies, as well as viscometry and X-ray crystallography. By comparison with the classical H2T4 system, H2TC3 exhibits a higher molar extinction coefficient but is more prone to self-association. Findings of note include that the copper(II)-containing form Cu(TC3) is adept at internalizing into single-stranded as well as B-form DNA, regardless of the base composition. Surprisingly, however, external binding of H2TC3 occurs within domains that are rich in adenine-thymine base pairs. The difference in the deformability of H2TC3 versus Cu(TC3) probably accounts for the reactivity difference. Finally, Zn(TC3) binds externally, as the metal center remains five-coordinate.
- Ghimire, Srijana,Fanwick, Phillip E.,McMillin, David R.
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- Synthesis, biological evaluation, and pharmacophore generation of uracil, 4(3H)-pyrimidinone, and uridine derivatives as potent and selective inhibitors of parainfluenza 1 (Sendai) virus
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Several new 6-oxiranyl-, 6-oxiranylmethyluracils, and pyrimidinone derivatives, synthesized by lithiation-alkylation sequence of 1,3,6-trimethyluracil, 1,3-dimethyl-6-chloromethyluracil, and 2-alkoxy-6-methyl-4(3H)-pyrimidinones, showed a potent and selective antiviral activity against Sendai virus (SV) replication. To gain insight into the structural features required for SV inhibition activity, the new compounds were submitted to a pharmacophore generation procedure using the program Catalyst. The resulting pharmacophore model showed high correlation and predictive power. It also rationalized the relationships between structural properties and biological data of these inhibitors of SV replication.
- Saladino,Crestini,Palamara,Danti,Manetti,Corelli,Garaci,Botta
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Read Online
- Synthesis of the tricyclic ABC ring subunit of mazamine A
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A new approach to the construction of the pyrrolo[2, 3 -i] isoquinoline, the core structure of manzamine A, is described.
- Li, Shouming,Kosemura, Seiji,Yamamura, Shosuke
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Read Online
- Organocatalytic diastereo- And enantioselective oxa-hetero-Diels-Alder reactions of enones with aryl trifluoromethyl ketones for the synthesis of trifluoromethyl-substituted tetrahydropyrans
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Tetrahydropyran derivatives are found in bioactives, and introduction of the trifluoromethyl group into molecules often improves biofunctions. Here we report diastereo- and enantioselective oxa-hetero-Diels-Alder reactions catalyzed by amine-based catalyst systems that afford trifluoromethyl-substituted tetrahydropyranones. Catalyst systems and conditions suitable for the reactions to provide the desired diastereomer products with high enantioselectivities were identified, and various trifluoromethyl-substituted tetrahydropyranones were synthesized with high diastereo- and enantioselectivities. Mechanistic investigation suggested that the reactions involve a [4 + 2] cycloaddition pathway, in which the enamine of the enone acts as the diene and the ketone carbonyl group of the aryl trifluoromethyl ketone acts as the dienophile. In this study, tetrahydropyran derivatives with the desired stereochemistry that are difficult to synthesize by previously reported methods were concisely obtained, and the range of tetrahydropyran derivatives that can be synthesized was expanded. This journal is
- Pasha, Maira,Tanaka, Fujie
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supporting information
p. 9242 - 9250
(2021/11/16)
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- Palladium/Copper-catalyzed Oxidation of Aliphatic Terminal Alkenes to Aldehydes Assisted by p-Benzoquinone
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The development of an anti-Markovnikov Wacker-type oxidation for simple aliphatic alkenes is a significant challenge. Herein, a variety of aldehydes can be selectively obtained from various unbiased aliphatic terminal alkenes using PdCl2(MeCN)2/CuCl in the presence of p-benzoquinone (BQ) under mild reaction conditions. Isomerization of the terminal alkene to the internal alkene was suppressed via slow addition of the starting material to the reaction mixture. In addition to the Pd catalyst, CuCl and BQ were essential in order to obtain the anti-Markovnikov product with high selectivity. Terminal alkenes bearing a halogen substituent afforded their corresponding aldehydes with high anti-Markovnikov selectivity. The halogen acts as a directing group in the reaction. DFT calculations indicate that a μ-chloro Pd(II)?Cu(I) bimetallic species with BQ coordinated to Cu is the catalytically active species in the case of a terminal alkene without a directing group.
- Komori, Saki,Yamaguchi, Yoshiko,Murakami, Yuka,Kataoka, Yasutaka,Ura, Yasuyuki
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p. 3946 - 3955
(2020/07/06)
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- NOVEL COMPOUNDS HAVING ESTROGEN RECEPTOR ALPHA DEGRADATION ACTIVITY AND USES THEREOF
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The present disclosure relates to novel compounds having estrogen receptor alpha degradation activity, pharmaceutical compositions containing such compounds, and their use in prevention and treatment of cancer and related diseases and conditions.
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Paragraph 0562
(2020/06/08)
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- Photo-organocatalytic synthesis of acetals from aldehydes
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A mild and green photo-organocatalytic protocol for the highly efficient acetalization of aldehydes has been developed. Utilizing thioxanthenone as the photocatalyst and inexpensive household lamps as the light source, a variety of aromatic and aliphatic aldehydes have been converted into acyclic and cyclic acetals in high yields. The reaction mechanism was extensively studied.
- Nikitas, Nikolaos F.,Triandafillidi, Ierasia,Kokotos, Christoforos G.
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supporting information
p. 669 - 674
(2019/02/14)
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- IDO inhibitors
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Presently provided are methods for (a) modulating an activity of indoleamine 2,3-dioxygenase comprising contacting an indoleamine 2,3-dioxygenase with a modulation effective amount of a compound as described in one of the aspects described herein; (b) treating indoleamine 2,3-dioxygenase (IDO) mediated immunosuppression in a subject in need thereof, comprising administering an effective indoleamine 2,3-dioxygenase inhibiting amount of a compound as described in one of the aspects described herein; (c) treating a medical conditions that benefit from the inhibition of enzymatic activity of indoleamine-2,3-dioxygenase comprising administering an effective indoleamine 2,3-dioxygenase inhibiting amount of a compound as described in one of the aspects described herein; (d) enhancing the effectiveness of an anti-cancer treatment comprising administering an anti-cancer agent and a compound as described in one of the aspects described herein; (e) treating tumor-specific immunosuppression associated with cancer comprising administering an effective indoleamine 2,3-dioxygenase inhibiting amount of a compound as described in one of the aspects described herein; and (f) treating immunosuppression associated with an infectious disease, e.g., HIV-I infection, comprising administering an effective indoleamine 2,3-dioxygenase inhibiting amount a compound as described in one of the aspects described herein.
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Page/Page column 303; 304
(2018/09/02)
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- Asymmetric Reductive Carbocyclization Using Engineered Ene Reductases
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Ene reductases from the Old Yellow Enzyme (OYE) family reduce the C=C double bond in α,β-unsaturated compounds bearing an electron-withdrawing group, for example, a carbonyl group. This asymmetric reduction has been exploited for biocatalysis. Going beyond its canonical function, we show that members of this enzyme family can also catalyze the formation of C?C bonds. α,β-Unsaturated aldehydes and ketones containing an additional electrophilic group undergo reductive cyclization. Mechanistically, the two-electron-reduced enzyme cofactor FMN delivers a hydride to generate an enolate intermediate, which reacts with the internal electrophile. Single-site replacement of a crucial Tyr residue with a non-protic Phe or Trp favored the cyclization over the natural reduction reaction. The new transformation enabled the enantioselective synthesis of chiral cyclopropanes in up to >99 % ee.
- Heckenbichler, Kathrin,Schweiger, Anna,Brandner, Lea Alexandra,Binter, Alexandra,Toplak, Marina,Macheroux, Peter,Gruber, Karl,Breinbauer, Rolf
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supporting information
p. 7240 - 7244
(2018/06/15)
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- FUSED 1,4-DIAZEPINES AS BET PROTEIN DEGRADERS
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The present disclosure provides compounds represented by Formula I: I, and the pharmaceutically acceptable salts, hydrates, and solvates thereof, wherein R1, R2a, R2b, R3, R4, Ar, L, X, Y, and B are as defined as set forth in the specification. The present disclosure also provides compounds of Formula I for use to treat a condition or disorder responsive to degradation of BET bromodomains such as cancer.
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Paragraph 0472
(2018/04/13)
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- Chemo- and Enantioselective Pd/B Hybrid Catalysis for the Construction of Acyclic Quaternary Carbons: Migratory Allylation of O-Allyl Esters to α- C-Allyl Carboxylic Acids
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We describe herein the asymmetric synthesis of α-allyl carboxylic acids containing an α-quaternary stereocenter by a chiral hybrid catalyst system comprising palladium and boron complexes. The reaction proceeded through palladium-catalyzed ionization of α,α-disubstituted O-allyl esters for the generation of chiral π-allyl palladium complex as an electrophile, boron-catalyzed enolization of the carboxylate part for the generation of chiral α,α-disubstituted carboxylic acid-derived enolates as a nucleophile, and enantioselective coupling between the thus-generated nucleophile and electrophile. Proper combinations of chiral ligands for the boron and palladium catalysts were crucial. The reaction proceeded chemoselectively at the α-position of the carboxylic acid group.
- Fujita, Taiki,Yamamoto, Tomohiro,Morita, Yuya,Chen, Hongyu,Shimizu, Yohei,Kanai, Motomu
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supporting information
p. 5899 - 5903
(2018/05/14)
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- Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics
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The amide moiety of peptides can be replaced for example by a triazole moiety, which is considered to be bioisosteric. Therefore, the carbonyl moiety of an amino acid has to be replaced by an alkyne in order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at Cα, such amide bond surrogates need a chiral moiety. Here the asymmetric synthesis of a set of 24 N-sulfinyl propargylamines is presented. The condensation of various aldehydes with Ellman's chiral sulfinamide provides chiral N-sulfinylimines, which were reacted with (trimethylsilyl)ethynyllithium to afford diastereomerically pure N-sulfinyl propargylamines. Diverse functional groups present in the propargylic position resemble the side chain present at the Cα of amino acids. Whereas propargylamines with (cyclo)alkyl substituents can be prepared in a direct manner, residues with polar functional groups require suitable protective groups. The presence of particular functional groups in the side chain in some cases leads to remarkable side reactions of the alkyne moiety. Thus, electron-withdrawing substituents in the Cα-position facilitate a base induced rearrangement to α,β-unsaturated imines, while azide-substituted propargylamines form triazoles under surprisingly mild conditions. A panel of propargylamines bearing fluoro or chloro substituents, polar functional groups, or basic and acidic functional groups is accessible for the use as precursors of peptidomimetics.
- Wünsch, Matthias,Schr?der, David,Fr?hr, Tanja,Teichmann, Lisa,Hedwig, Sebastian,Janson, Nils,Belu, Clara,Simon, Jasmin,Heidemeyer, Shari,Holtkamp, Philipp,Rudlof, Jens,Klemme, Lennard,Hinzmann, Alessa,Neumann, Beate,Stammler, Hans-Georg,Sewald, Norbert
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supporting information
p. 2428 - 2441
(2017/12/06)
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- MONOFUNCTIONAL INTERMEDIATES FOR LIGAND-DEPENDENT TARGET PROTEIN DEGRADATION
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The present disclosure provides compounds represented by Formula I: and the salts or solvates thereof, wherein X, L, Y, and B are as defined in the specification. Compounds having Formula I are immunomodulators and/or monofunctional synthetic intermediates that can be used to prepare small-molecule drug conjugates.
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Paragraph 0949
(2017/11/04)
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- Cascade oxime formation, cyclization to a nitrone, and intermolecular dipolar cycloaddition
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Simple haloaldehydes, including enolisable aldehydes, were found to be suitable for the formation of cyclic products by cascade (domino) condensation, cyclisation, dipolar cycloaddition chemistry. This multi-component reaction approach to heterocyclic compounds was explored by using hydroxylamine, a selection of aldehydes, and a selection of activated dipolarophiles. Initial condensation gives intermediate oximes that undergo cyclisation with displacement of halide to give intermediate nitrones; these nitrones undergo in situ intermolecular dipolar cycloaddition reactions to give isoxazolidines. The cycloadducts from using dimethyl fumarate were treated with zinc/acetic acid to give lactam products and this provides an easy way to prepare pyrrolizinones, indolizinones, and pyrrolo[2,1-a]isoquinolinones. The chemistry is illustrated with a very short synthesis of the pyrrolizidine alkaloid macronecine and a formal synthesis of petasinecine.
- Furnival, Rachel C.,Saruengkhanphasit, Rungroj,Holberry, Heather E.,Shewring, Jonathan R.,Guerrand, Hélène D. S.,Adams, Harry,Coldham, Iain
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p. 10953 - 10962
(2016/12/06)
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- Overcoming Problems at Elaboration and Scale-up of Liquid-Phase Pd/C Mediated Catalytic Hydrogenations in Pharmaceutical Production
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The practical solutions for scale-up and production of intermediates or precursors of pharmaceuticals by liquid-phase Pd/C mediated hydrogenation can be of considerable interest and deserve broader attention even if they have not been the focus of previously published research due to regulations of patent law. The practical obstacles are persistent and have been known for a long time, but for the most part remained unpublished. The most important discoveries and solutions that contributed to the successful scale-up of hydrogenations for pharmaceutical production were the following: (i) the poisoning of Pd/C catalyst with Fe2+ ions for the selective hydrogenation of 2,6-dimethyl-1-nitrosopiperidine to the corresponding hydrazo compound; (ii) alloying of the deposited Pd metal with Cu for converting the aromatic acid chlorides into the corresponding aldehydes; (iii) alteration of the pH of the reaction mixture to basic values which enhanced the stereoselectivity of paracetamol hydrogenation; (iv) a useful modification of the catalyst preparation process, i.e., the acidification of the catalyst resulted in the hydrogenolysis of benzylic OH in a molecule containing a basic N atom; (v) use of two liquid phases, altogether a four-phase system, which permitted the hydrogenolysis of the S-S bond in a potential catalyst poisoning molecule; (vi) the preservation of the metallic Pd surface of the catalyst by saturation of the reaction mixture with hydrogen, resulting in a high H2/substrate ratio, increased the aldehyde yield in the hydrogenation of 4-chloro-butyric-acid-chloride by avoiding the unwanted poisoning effect of the hydrochloric acid. In the present article, these problems and their solutions, as they emerged during the scale-up of the processes, will be discussed in detail.
- Tungler, Antal,Szabados, Erika
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p. 1246 - 1251
(2016/07/23)
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- ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES
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Imidazophenanthridine ligands and metal complexes are provided. The compounds exhibit improved stability through a linking substitution that links a nitrogen bonded carbon of an imidizole ring to a carbon on the adjacent fused aryl ring. The compounds may be used in organic light emitting devices, particularly as emissive dopants, providing devices with improved efficiency, stability, and manufacturing. In particular, the compounds provided herein may be used in blue devices having high efficiency.
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- Spiroacetal formation through telescoped cycloaddition and carbon-hydrogen bond functionalization: Total synthesis of bistramide A
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Spiroacetals can be formed through a one-pot sequence of a hetero-Diels-Alder reaction an oxidative carbon-hydrogen bond cleavage and an acid treatment. This convergent approach expedites access to a complex molecular subunit which is present in numerous biologically active structures. The utility of the protocol is demonstrated through its application to a brief synthesis of the actin-binding cytotoxin bistramideA.
- Han, Xun,Floreancig, Paul E.
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supporting information
p. 11075 - 11078
(2015/03/30)
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- Solar photochemistry: Optimisation of the photo Friedel-Crafts acylation of naphthoquinones
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A practical and robust photo Friedel-Crafts acylation of naphthoquinones is described. Although the reaction proceeds slowly in sunlight, the optimised conditions offer a substantial improvement to those already reported, by the utilisation of a more reliable and practical 'sun-mimicking' light source, a less hazardous solvent system (trifluorotoluene) and faster reaction times. Using these conditions, the reaction scope has been expanded to include functionalised aldehyde and naphthoquinone substrates, affording the desired photo-products in acceptable to excellent yields (17-81%). Factors influencing the regiochemistry of the photo Friedel-Crafts reaction on unsymmetrical naphthoquinones have also been investigated.
- Mitchell, Lorna J.,Lewis, William,Moody, Christopher J.
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supporting information
p. 2830 - 2842
(2013/10/08)
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- Catalytic enantioselective formal Hetero-Diels-Alder reactions of enones with isatins to give spirooxindole tetrahydropyranones
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Organocatalytic formal hetero-Diels-Alder reactions of enones with isatins, which gave highly enantiomerically enriched functionalized spirooxindole tetrahydropyranones via an enamine-based mechanism, were developed. The catalyst systems were identified by a screen of combinations of amines, acids, and additives. With the identified catalyst systems, various spirooxindole tetrahydropyranones were synthesized in high yields with high diastereo- and enantioselectivities (see scheme). Copyright
- Cui, Hai-Lei,Tanaka, Fujie
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supporting information
p. 6213 - 6216
(2013/07/04)
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- Synthesis of indolo[2,3-a]quinolizine and hexahydro-1H-indolizino[8,7-b] indole derivatives by cascade condensation, cyclization, and Pictet-Spengler reaction: An application to the synthesis of (±)-harmicine
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Synthesis of indole alkaloid related compounds using Schiff base formation, intramolecular cyclization (or N-alkylation), and Pictet-Spengler reaction as a cascade one pot condensation has been reported. The cascade chemistry has been applied to the synthesis of (±)-harmicine as a key step.
- Sanaboina, Chakrapani,Jana, Samaresh,Chidara, Sridhar,Patro, Balaram,Raolji, Gajendrasinh Balvantsinh,Eppakayala, Laxminarayana
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p. 5027 - 5029,3
(2020/07/30)
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- Total syntheses of (-) epilupinine and (-)-tashiromine using imino-aldol reactions
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Short routes to enantiomerically pure indolizidine and quinolizidine alkaloids have been developed using imino-aldol reactions of enolates derived from phenyl 5-chlorovalerate. High levels of syn selectivity (dr ～13-16:1) were obtained using lithium enolates of phenyl esters in combination with tert-butylsulfinyl imines. The imino-aldol adducts were deprotected and cyclized to afford (-)-epilupinine ((-)-2) and (-)-tashiromine ((-)-1) in two further steps.
- Cutter, Amanda C.,Miller, Iain R.,Keily, John F.,Bellingham, Richard K.,Light, Mark E.,Brown, Richard C. D.
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supporting information; experimental part
p. 3988 - 3991
(2011/09/16)
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- Total synthesis of (+)-clavolonine, (-)-deacetylfawcettiine, and (+)-acetylfawcettiine
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(Figure Presented) Three lycopodium alkaloids have been prepared by using a new strategy for constructing the central cyclohexane core (see scheme; o-DPPB = ortte-diphenylphosphanyl benzoyl). Thus stereoselec-tive synthesis relying on substrate control was implemented; the key step involved a sequence of a (o-DPPB)-directed hydroformylation/carbonylene reaction and (oDPPB)-directed hydroformylation.
- Laemmerhold, Kai M.,Breit, Bernhard
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supporting information; experimental part
p. 2367 - 2370
(2010/08/04)
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- PROCESS FOR THE PREPARATION OF 1-[[[3-[2-(DIMETHYLAMINO)ETHYL]-1H-INDOL-5-YL]METHYL]SULFONYL] PYRROLIDINE AND ITS PHARMACEUTICALLY ACCEPTABLE SALTS
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The present invention relates to an improved process for the preparation of 1-[[[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl] methyl] sulfonyl]pyrrolidine compound of formula- 1 and its pharmaceutically acceptable salts.
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Page/Page column 26
(2010/11/03)
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- Comparative study of the N-isobutyl-(2E,6Z)-dodecadienamide chemical and electrochemical syntheses
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In order to show the advantages and limitations of organic electrosynthesis in the total synthesis of a natural product, one of the promising green chemistry techniques in organic chemistry, the synthesis of N-isobutyl-(2E,6Z)- dodecadienamide (3) was undertaken. Chemical and electrochemical routes that use the same intermediates were used to carry out the syntheses. Four reactions were compared from a green chemistry point of view in the synthesis of 3: (a) alcohol to aldehyde oxidation, (b) the Horner-Emmons reaction, (c) carboxylic acid amidation with triphenylphosphonium ions and (d) the Wittig reaction. All the electrolyses were carried out in non-divided cells at a constant current. The electrochemical method in the oxidation reaction of alcohols and the carboxylic acid amidation gave better yields (95% and 67%, respectively) than the corresponding chemical reactions. The Horner-Emmons reaction gave the same yields in both techniques (80-85%); however, the electrochemical method was more environmentally friendly, due to the fact that the base used was electrogenerated, avoiding corrosive and sensitive base manipulation. Finally, the electrochemical Wittig reaction was unsuccessful in the different experimental conditions attempted, and only the chemical method produced the target product. This study demonstrated that organic electrochemistry can be a reliable method for the synthesis of important intermediates, but not all electrochemical reactions can compete with the already well-established methods of organic chemistry.
- Palma, Agustin,Cardenas, Jorge,Frontana-Uribe, Bernardo A.
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experimental part
p. 283 - 293
(2010/04/22)
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- An alternative synthesis of (8E,10Z)-tetradeca-8,10-dienal, sex pheromone of horse-chestnut leafminer (Cameraria ohridella)
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The stereoselective synthesis of the sex pheromone of horse-chestnut leafminer was efficiently carried out using methodology based on the Pd(0)-catalyzed cross-coupling of 1-pentynylmagnesium bromide with the corresponding vinyl iodides as the key step.
- Grodner, Jacek
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experimental part
p. 1648 - 1654
(2009/05/09)
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- Nickel-catalyzed asymmetric cross-couplings of racemic propargylic halides with arylzinc reagents
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A stereoconvergent method for the catalytic asymmetric Negishi cross-coupling of racemic secondary propargylic halides with arylzinc reagents has been developed. Neither family of compounds has previously been shown to be a suitable partner in such coupling processes. From a practical point of view, it is noteworthy that the catalyst components (NiCl2·glyme and pybox ligand 1) are commercially available. Copyright
- Smith, Sean W.,Fu, Gregory C.
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supporting information; experimental part
p. 12645 - 12647
(2009/05/09)
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- Nickel-catalyzed Negishi cross-couplings of secondary nucleophiles with secondary propargylic electrophiles at room temperature
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(Chemical Equation Presented) Mild thing: The first nickel-based catalysts for cross-couplings of secondary organometallic nucleophiles with secondary alkyl electrophiles have been developed. Thus, Negishi reactions proceed under mild conditions (at room temperature with no basic activators) in the presence of NiCl2·glyme and a tridentate ligand (see scheme).
- Smith, Sean W.,Fu, Gregory C.
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supporting information; experimental part
p. 9334 - 9336
(2009/05/16)
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- Oxidation of unsaturated primary alcohols and ω-haloalkanols with 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate
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Unsaturated primary alcohols and ω-haloalkanols, all applied in pheromone synthesis, are oxidized to the corresponding aldehydes using 4-acetylamino-2,2,6,6-tetramethylpiperidine- 1-oxoammonium tetrafluoroborate (1a). Three methods are compared with one another; oxidations with la and silica gel, oxidations with la in the presence of pyridine, and pyridinium chlorochromate (PCC). Georg Thieme Verlag Stuttgart.
- Zakrzewski, Jerzy,Grodner, Jacek,Bobbitt, James M.,Karpinska, Monika
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p. 2491 - 2494
(2008/02/13)
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- Copper-catalyzed asymmetric conjugate addition of trialkylaluminium reagents to trisubstituted enones: Construction of chiral quaternary centers
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Me3Al, Et1Al, and vinylalane species undergo enantioselective conjugate addition to a wide range of 2- or 3-substituted enones (cyclopent-2enones, cyclohex-2-enones, 3-methyl cyclohept-2-enone) in the presence of catalytic amount of copper salt (copper thiophene carboxylate, [Cu(CH3-CN)4]BF4 or [CuOTf]2· C6H6) and tropos-phosphoramidite-based ligand. Thus, chiral quaternary centers can be built, with up to 98% ee after rigorous optimization of experimental conditions. It was shown that the main important parameter was the order of the introduction of the reagents. Then, the generated enantioenriched aluminium enolates and the chiral conjugate adducts were functionalized and used for subsequent reactions.
- Vuagnoux-D'Augustin, Magali,Alexakis, Alexandre
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p. 9647 - 9662
(2008/12/21)
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- Quick access to optically pure 2-(1-hydroxybenzyl)piperidine and pyrrolidine
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Optically pure 2-(1-hydroxybenzyl)piperidine and pyrrolidine were prepared by reaction of oxygenated 2-(p-tolylsulfinyl)benzyl carbanions with the appropriate chlorinated N-sulfinylimines followed by subsequent elimination of the sulfinyl groups. The main reaction is a tandem process involving nucleophilic addition of the sulfinylbenzyl carbanion to the C=N bond followed by intramolecular elimination of the chlorine by the resulting amide. The matched pair of the reagents (exhibiting the same configuration at their respective sulfinyl moieties) evolves with a complete control of the stereoselectivity at the two newly created chiral carbons. Georg Thieme Verlag Stuttgart.
- Ruano, Jose Luis Garcia,Aleman, Jose,Cid, M. Belen
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p. 687 - 691
(2007/10/03)
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- Stereochemistry of the cyclization of alkoxy-substituted 5-hexenyllithiums: Effect of solvent and lithium iodide on diastereoselectivity
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The stereochemistry of the cyclization of 4-methoxy-5-hexenyllithium, 4-(methoxymethoxy)-5-hexenyllithium, 4-tert-butoxy-5-hexenyllithium, and 3-methoxy-5-hexenyllithium, each of which was generated from the corresponding iodide by low-temperature lithium-iodine exchange, has been studied in a variety of solvent systems. The results of these studies demonstrate that the stereochemical outcome of the cyclizations of alkoxy-substituted 5-hexenyllithiums may be profoundly affected by the medium in which the ring closures are conducted. The etiology of these often dramatic solvent effects is attributed to the ability of certain lithiophilic ligands to competitively complex the lithium iodide salt that is present as a co-product from the exchange reaction used to prepare the organolithiums.
- Bailey, William F.,Jiang, Xinglong
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p. 3183 - 3194
(2007/10/03)
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- Generation of alkyl hypochlorites in oxidation of alcohols with carbon tetrachloride catalyzed by vanadium and manganese compounds
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Primary alcohols and diols with various structures were subjected to transformations into esters, aldehydes, ketones, and lactones under the action of carbon tetrachloride in the presence of manganese compounds (MnCl 2, MnO2, Mn(OAc)2, Mn(acac)3) and vanadium compounds (VCl5, V2O5, VO(acac) 2) as catalysts. These transformation proceeded with the involvement of alkyl hypochlorites, which were generated in the course of oxidation of alcohols with carbon tetrachloride catalyzed by manganese or vanadium compounds. The optimum molar ratios between the catalyst and reagents were determined, and the reaction conditions for the highly selective synthesis of esters, aldehydes, ketones, and lactones from alcohols were found.
- Khusnutdinov,Shchadneva,Baiguzina,Lavrentieva,Dzhemilev
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p. 2074 - 2079
(2007/10/03)
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- Oxidation of primary alkyl triflates to the corresponding aldehydes via alkoxy(N-tert-butylamino)(methyl)sulfonium triflates
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Various alkoxy(N-tert-butylamino)(methyl)sulfonium triflates are prepared by selective O-alkylation of N-tert-butylmethanesulfinamide (4c) with primary alkyl trifluoromethane-sulfonates (triflates). Successive treatment of thus formed alkoxyaminosulfonium salts with DBU smoothly affords the corresponding aldehydes in good yields. The sequential combination of the two reactions provides a new method for oxidation of primary alkyl triflates to aldehydes, and the present study suggests the existence of alkoxysulfilimines as intermediates of the previously-reported direct oxidation of alcohols by using N-tert-butylphenylsulfinimidoyl chloride (1a) and DBU.
- Kitagawa, Hideo,Matsuo, Jun-ichi,Iida, Daisuke,Mukaiyama, Teruaki
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p. 580 - 581
(2007/10/03)
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- An asymmetric aminohydroxylation approach to the azepine core of (-)-balanol
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(equation presented) An efficient formal synthesis of the potent protein kinase C inhibitor (-)-balanol that relies on a modified asymmetric aminohydroxylation of the α,β-unsaturated aryl ester (1) is reported. The aryl ester functionality and the dihydroquinyl alkaloid ligand system (DHQ)2-AQN are used to control the regio- and enantioselectivity of the process.
- Masse, Craig E.,Morgan, Adam J.,Panek, James S.
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p. 2571 - 2573
(2007/10/03)
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- Synthesis and structure-activity relationships of a new class of selective EP3 receptor agonist, 13,14-didehydro-16-phenoxy analogues of prostaglandin E1
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A series of 13,14-didehydro-16-phenoxy analogues of prostaglandin E1 was synthesized and their agonistic activity on EP receptor subtypes was evaluated. 13,14-Didehydro-16-phenoxy-1-decarboxy analogues, 7e and 7f, display highly selective activity on the EP3 receptor subtype, thus, their utility as a selective anti-ulcer agent can be expected. (C) 2000 Elsevier Science Ltd.
- Shimazaki, Youichi,Kameo, Kazuya,Tanami, Tohru,Tanaka, Hideo,Ono, Naoya,Kiuchi, Youichi,Okamoto, Sentaro,Sato, Fumie,Ichikawa, Atsushi
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p. 353 - 362
(2007/10/03)
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- Asymmetric synthesis of cyclic β-amino acids
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A convenient synthesis of cyclic β-amino acid derivatives (5-, 6- and 7-rings) is achieved via a four step sequence: (i) stereoselective Michael addition of substituted α-methylbenzylamines to α,β-unsaturated chloroesters; (ii) CAN-mediated deprotection; (iii) cyclisation and (iv) α-chloroethyl chloroformate-mediated α-methylbenzylamine deprotection.
- O'Brien,Porter,Smith
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p. 1336 - 1338
(2007/10/03)
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- N-(4-methylbenzenesulfonyl)- pyrrolidines and piperidines by a tandem S(N)2-Michael addition reaction
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A tandem S(N)2-Michael addition sequence has been developed for the preparation of N-(4-methylbenzenesulfonyl)- pyrrolidines and piperidines bearing functionalized side chains at C-2.
- Bunce, Richard A.,Allison, Jeffrey C.
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p. 2175 - 2186
(2007/10/03)
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- Preparation of 4,4-dimethoxybutyl chloride from γ-butyrolactone
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4,4-Dimethoxybutyl chloride 4, an important alternate for the synthesis of 1,5- and 1,6-dicarbonyl functionalities, has been synthesized from γ-butyrolactone.
- Athar, Taimur
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p. 1037 - 1038
(2007/10/03)
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- Biologically active acylated amino acid derivatives
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The present invention relates to novel compounds which possess a broad range of useful biological activities. These compounds can maintain, increase, or restore sensitivity of cells to therapeutic or prophylactic agents. They can also suppress, modify, or significantly reduce an immune response, including an autoimmune response in a mammal. This invention also relates to pharmaceutical compositions comprising these compounds. The compounds and pharmaceutical compositions of this invention are particularly well-suited for treatment of multi-drug resistant cells, for prevention of the development of multi-drug resistance, for use in multi-drug resistant cancer therapy, and for prevention or treatment of graft rejection and various autoimmune diseases.
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- 8-SUBSTITUTED TETRAHYDRO-BETA-CARBOLINES
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The present invention provides novel tetrahydro-beta-carboline compounds and intermediates having useful central nervous system activity. The invention provides formulations and methods for using the tetrahydro-beta-carboline and related intermediate compounds. Finally, the invention provides an article of manufacture.
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- INTERMEDIATES TO TETRAHYDRO-BETA-CARBOLINES
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3-Ethanamine and 3-ethanamine related compounds are provided that are useful intermediates and have beneficial central nervous system activity.
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- METHOD FOR TREATING 5HT2B RECEPTOR RELATED CONDITIONS
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The present invention provides methods for binding a 5-HT 2B receptor in mammals using a both known and novel compounds. Further, the invention provides a method for treating or preventing 5-HT 2B related conditions. Finally, the invention provides an article of manufacture.
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- TETRAHYDRO-PYRIDO-INDOLE
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The present invention provides pentacyclic pyrido[3,4-b] indoles having useful central nervous system activity.
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- Intramolecular Carbometallation of Organozinc Reagents
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The intramolecular cyclization reaction of primary or secondary alkenylzincs leads to a cyclopentylmethylzinc derivatives in a totally regiospecific 5-exo-trig cyclization in the presence of a highly sensitive function.
- Meyer, Christophe,Marek, Ilane,Courtemanche, Gilles,Normant, Jean-F.
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p. 11665 - 11692
(2007/10/02)
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- Tetrahydro-pyrido-indole
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The present invention provides a new Pictet-Spengler process useful for preparing tetrahydro-beta-carboline compounds.
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- ELECTROCHEMICAL AND CHEMICAL OXIDATION OF ALCOHOLS IN A TWO-PHASE SYSTEM USING N-OXOPIPERIDINUM SALT: SYNTHESIS OF 4-CHLOROBUTANAL, FORMYLCYCLOPROPANES, AND m-PHENOXYBENZALDEHYDE
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Oxidation of 4-chlorobutanol-1, cyclopropylcarbinols, and m-phenoxybenzyl alcohol with electrogenerated bromine, molecular bromine, and sodium hypochlorite using N-oxopiperidinium salt in the two-phase system CH2Cl2-water gave the corresponding carbonyl compounds with good yields.Keywords: indirect electrooxidation, 4-chlorobutanol-1, cyclopropylcarbinols, m-phenoxybenzyl alcohol, 2,2,6,6-tetramethyl-4-benzoyloxypiperidine-1-oxide, bromine, sodium hypochloriate, 4-chlorobutanal, formylcyclopropanes, m-phenoxybenzaldehyde.
- Ogibin, Yu. N.,Khusid, A. Kh.,Nikishin, G. I.
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p. 735 - 739
(2007/10/02)
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