- Direct and practical Gilman-Speeter synthesis of 3,4-trisubstituted β-lactams via the Thorpe-Ingold effect
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A highly efficient Gilman-Speeter synthesis of 3,4-trisubstituted β-lactams possessing a 4-aryl substituent is described, employing a direct, uncatalyzed Mannich reaction between TMS imines and TMS ketene acetals. The process avoids cryogenic conditions, making it more amenable to process-scale use than related methods for β-lactam synthesis. A Gilman-Speeter diastereoselective version using a sulfinyl imine and leading to homochiral sulfinyl β-aminoester is also presented.
- Panagiotou, Maria,Demos, Vasileios,Magriotis, Plato Α.
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supporting information
(2020/09/09)
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- Access to nitriles from aldehydes mediated by an oxoammonium salt
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A scalable, high yielding, rapid route to access an array of nitriles from aldehydes mediated by an oxoammonium salt (4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate) and hexamethyldisilazane (HMDS) as an ammonia surrogate has been developed. The reaction likely involves two distinct chemical transformations: reversible silyl-imine formation between HMDS and an aldehyde, followed by oxidation mediated by the oxoammonium salt and desilylation to furnish a nitrile. The spent oxidant can be easily recovered and used to regenerate the oxoammonium salt oxidant.
- Kelly, Christopher B.,Lambert, Kyle M.,Mercadante, Michael A.,Ovian, John M.,Bailey, William F.,Leadbeater, Nicholas E.
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supporting information
p. 4241 - 4245
(2015/04/14)
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- Catalytic enantioselective one-pot aminoborylation of aldehydes: A strategy for construction of nonracemic α-amino boronates
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We report a strategy for the conversion of aldehydes to enantiomerically enriched α-amino boronates through the intermediacy of in situ-generated silylimines. This transformation is brought about by Pt-catalyzed asymmetric addition of B2(pin)s
- Hong, Kai,Morken, James P.
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supporting information
p. 9252 - 9254
(2013/07/26)
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- Three-component coupling sequence for the regiospecific synthesis of substituted pyridines
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A de novo synthesis of substituted pyridines is described that proceeds through nucleophilic addition of a dithiane anion to an α,β- unsaturated carbonyl followed by metallacycle-mediated union of the resulting allylic alcohol with preformed trimethylsilane-imines (generated in situ by the low-temperature reaction of lithium hexamethyldisilazide with an aldehyde) and Ag(I)- or Hg(II)-mediated ring closure. The process is useful for the convergent assembly of di- through penta-substituted pyridines with complete regiochemical control.
- Chen, Ming Z.,Micalizio, Glenn C.
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supporting information; experimental part
p. 1352 - 1356
(2012/03/11)
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- Catalytic intermolecular hetero-dehydro-diels-alder cycloadditions: Regioand diasteroselective synthesis of 5,6-dihydropyridin-2-ones
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A novel catalyzed intermolecular heterodehydro-Diels-Alder reaction between push-pull 1,3-dien-5-ynes and aldimines or silylaldimines is reported. The sequence is promoted both by gold(I) or silver(I) catalysts and leads to the diastereo- and regioselective formation of 5,6- dihydropyridin-2-ones.
- Fernandez-Garcia, Jesus Manuel,Fernandez-Rodriguez, Manuel A.,Aguilar, Enrique
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supporting information; experimental part
p. 5172 - 5175
(2011/12/04)
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- T-CELL INHIBITING COMPOUNDS AND THEIR USE FOR THE TREATMENT OF T-CELL-MEDIATED DISEASES
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The present invention relates to compounds of formula IA or IB. The present invention also concerned to a method of treating immunologic diseases or pathological conditions in association with T cell involving an immunologic component using T-cell inhibitors, optionally in combination with one or more other drugs selected from steroids, DMARDs, NSAIDs, immunosuppressive, and biological modifiers, pharmaceutical compositions comprising said compounds of formula IA or IB together with said other drugs, and the use of T-cell inhibitors for the manufacture of a pharmaceutical composition for the treatment of immunologic diseases or pathological conditions involving an immunologic component.
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Page/Page column 26-27
(2008/12/07)
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- Asymmetric synthesis of propargylamides via 3,3′-disubstituted binaphthol-modified alkynylboronates
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(Chemical Equation Presented) Alkynylboronates derived from 3,3′-disubstituted-2,2′-binaphthols react with various N-acylimines to give the expected chiral propargylamides with up to 99% ee. This new methodology was applied to the first enantioselective s
- Wu, T. Robert,Chong, J. Michael
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- A one-pot aza-Wittig based solution and polymer supported route to amines
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This paper presents a high yielding one-pot solution phase and polymer supported synthesis of a range of primary and secondary amines starting from azides and aldehydes. The synthesis utilises a tandem process which begins with an aza-Wittig reaction between the aldehyde and an iminophosphorane, followed by reduction, or organometallic 1,2-addition reaction, of the resultant imine. The requisite iminophosphoranes were accessed using the highly efficient Staudinger reaction between the azide starting material and a phosphine. The process was applicable to the solid phase by the use of polymer supported iminophosphoranes and polymer supported cyanoborohydride.
- Hemming,Bevan,Loukou,Patel,Renaudeau
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p. 1565 - 1568
(2007/10/03)
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- A trans-stereoselective synthesis of 3-halo-4-alkyl(aryl)-NH-azetidin-2-ones
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Conrotatory ring closure of 1-halo-3-aza-4-alkyl-1,3-dienes in refluxing toluene gives rise to 3-halo-4-aryl-2-azetidinones in satisfactory yields. Dehalogenation of the resulting β-lactams by tris(trimethylsilyl)silane furnished 3-unsubstituted azetidino
- Bandini, Elisa,Favi, Gianfranco,Martelli, Giorgio,Panunzio, Mauro,Piersanti, Giovanni
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p. 1077 - 1079
(2007/10/03)
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- Lithium perchlorate mediated three component reaction for the preparation of primary amines
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In the presence of lithium perchlorate in diethyl ether, LPDE, a three- component reaction between aldehydes, sodium hexamethyldisilazane or lithium hexamethyldisilazane, LHMDS, and different nucleophiles proceeds smoothly to afford primary amines in good yields.
- Saidi, Mohammad R.,Javanshir, Shahrzad,Mojtahedi, Mohammad M.
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p. 330 - 331
(2007/10/03)
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- Anti-tumor compounds, pharmaceutical compositions, methods for preparation thereof and for treatment
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The present invention is directed to novel taxanes useful as chemotherapeutic agents or their precursors. Processes for preparing the novel taxanes include coupling reactions, in the presence of a base, of baccatin of formula (III) or (IV) STR1 with β-lac
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- Convenient Access to Primary Amines by Employing the Barbier-Type Reaction of N-(Trimethylsilyl)imines Derived from Aromatic and Aliphatic Aldehydes
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A new versatile preparation of primary amines via benzylation of aromatic and aliphatic aldimines is described. Sonochemical and traditional methods for generation of the reactive intermediates are compared and contrasted. Competitive reactions were analyzed via free energy relationships to support the proposed alkylative mechanism.
- Gyenes, Ferenc,Bergmann, Kathryn E.,Welch, John T.
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p. 2824 - 2828
(2007/10/03)
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- Anti-tumor compounds, pharmaceutical compositions, methods for preparation thereof and for treatment
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The present invention is directed to novel taxanes useful as chemotherapeutic agents or their precursors. Processes for preparing the novel taxanes include coupling reactions, in the presence of a base, of baccatin of formula (III) or (IV) STR1 with β-lac
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- New and efficient approaches to the semisynthesis of taxol and its C-13 side chain analogs by means of β-lactam synthon method
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Highly efficient chiral ester enolate-imine condensation giving 3-hydroxy-4-aryl-β-lactams with excellent enantiomeric purity is successfully applied to the asymmetric synthesis of the enantiomerically pure taxol C-13 side chain, N-benzoyl-(2R,3S)-3-phenyl-isoserine and its analogs. (3R,4S)-N-benzoyl-3-(1-ethoxyethoxy)-4-phenyl-2-azetidinone readily derived from the 3-hydroxy-4-phenyl-β-lactam is coupled with protected baccatin IIIs, followed by deprotection to give optically pure taxol and 10-deacetyl-7,10-bis(Troc)-taxol in good yields. Fully assigned 1H, 13C, and 2D (COSY and HETCOR) NMR spectra of taxol thus synthesized are shown and discussed.
- Ojima, Iwao,Habus, Ivan,Zhao, Mangzhu,Zucco, Martine,Park, Young Hoon,Sun, Chung Ming,Brigaud, Thierry
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p. 6985 - 7012
(2007/10/02)
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- Preparation of Primary Amines and 2-Azetidinones via N-Trimethylsilyl Imines
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Nonenolizable aldehydes react with lithium bis(trimethylsilyl)amide at ambient temperatures to afford solutions of N-trimethylsilyl aldimines.Treatment of these solutions with Grignard reagents or alkyllithiums followed by an aqueous workup gives primary amines in moderate to excellent yields.Treatment of N-trimethylsilyl aldimines with ester enolates provides an expedient route to 1-unsubstituted 2-azetidinones.
- Hart, David J.,Kanai, Ken-ichi,Thomas, Dudley G.,Yang, Teng-Kuei
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p. 289 - 294
(2007/10/02)
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