- The Ugly Duckling Metamorphosis: The Ammonia/Formaldehyde Couple Made Possible in Ugi Reactions.
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Ugi reactions are still a challenge when the concomitant use of ammonia and formaldehyde is required. Herein, we propose a strategy to overcome this challenge using hexamethylenetetramine (HMTA) as a singular key for the employment of these two simple starting materials in the Ugi reaction. Acylaminoacetamide derivatives were prepared in good to excellent yields by this new methodology. The scope and optimization of the reaction conditions were investigated. This novel methodology was successfully applied in the synthesis of two different diketopiperazines (DKPs) using the Ugi/Deprotection+Activation/Cyclization (UDAC) method. A continuous flow approach was also used in this methodology.
- Rosalba, Thaissa Pasquali F.,Kas, Samia Sayegh A.,Sampaio, Ana Beatriz S.,Salvador, Carlos Eduardo M.,Andrade, Carlos Kleber Z.
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p. 2831 - 2842
(2021/05/13)
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- The Synthesis of Ketone-Derived Enamides by Elimination of HCN from Cyanoamides
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Treatment of easily available ketone-derived cyanoamides with NaOtBu leads to enamides in a simple, scalable, and inexpensive one-step operation in good yield. Enamides not stabilized by conjugation or by inclusion in a ring can also be prepared. An E1cB mechanism consistent with all results and observations, is proposed. The Z geometry of the product enamide is highly favoured, and the regioselectivity can be directed by one′s choice of protecting group.
- Coussanes, Guilhem,Gaus, Katharina,O'Sullivan, Anthony C.
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p. 4176 - 4188
(2016/08/26)
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- A general simple methodology for synthesis of isonitriles using benzene-1,3-disulfonyl dichloride
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Isonitrile derivatives have been synthesized in good to high yields by dehydration of aliphatic and aromatic formamides in the presence of benzene-1,3-disulfonyl dichloride as easy and efficient reagent.
- Ghorbani-Vaghei, Ramin,Amiri, Mostafa,Veisi, Hojat
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- The development of an aza-C-glycoside library based on a tandem staudinger/aza-wittig/ugi three-component reaction
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We report the tandem Staudinger/aza-Wittig/Ugi three-component reaction mediated synthesis of a 64-member compound library of aza-C-glycosides. The library is composed of four pyrrolidine and three piperidine scaffolds, onto which a number of functional groups is grafted to form seven sublibraries. Variation in the library is achieved by transformation of two pentoses and a hexose into the corresponding 4-azidopentanal and 5-azidohexanal derivatives as precursors for the Staudinger/aza-Wittig process. Further variation is achieved by using different isocyanides as well as protective- and functional-group manipulations on the fully protected Ugi-3CR intermediates. Preliminary biological evaluation of the compound library revealed several low micromolar inhibitors of human acid glucosylceramidase.
- Wennekes, Tom,Bonger, Kimberly M.,Vogel, Katrin,Van Den Berg, Richard J. B. H. N.,Van Der Marel, Gijsbert A.,Overkleeft, Herman S.,Strijland, Anneke,Donker-Koopman, Wilma E.,Aerts, Johannes M. F. G.
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p. 6420 - 6454,35
(2020/09/16)
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- Synthetic studies toward lapidilectine-type Kopsia alkaloids
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A rapid synthesis of the tetracyclic core of Kopsia indole alkaloids related to lapidilectine B, grandilodine C, and tenuisine A is reported. Key to the success of this route was an efficient and scalable Ugi four-component coupling to install all the necessary carbons found in the natural products.
- Schultz, Erica E.,Pujanauski, Brian G.,Sarpong, Richmond
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supporting information; experimental part
p. 648 - 651
(2012/03/08)
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- Multicomponent reactions of cyclobutanones
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Cyclobutanones are essentially unknown as reactants in isonitrile-based multicomponent reactions. Ugi reactions of cyclobutanone and Passerini reactions of tetramethylcyclobutane-1,3-dione have been performed in this work. These reactions are significantly enhanced by being conducted in water, a subject of recent interest whose basis is still in question but whose effects are beyond doubt. The Ugi reaction of cyclobutanone has been used in a brief synthesis of an aspartame analogue.
- Pirrung, Michael C.,Wang, Jianmei
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scheme or table
p. 2958 - 2963
(2009/09/05)
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- Microwave-assisted synthesis of isonitriles: A general simple methodology
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(Chemical Equation Presented) A facile conversion of formamides to isonitriles under very mild conditions and microwave irradiation is described. This simple and efficient method has been applied for the synthesis of both aliphatic and aromatic isonitriles in high yields.
- Porcheddu, Andrea,Giacomelli, Giampaolo,Salaris, Margherita
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p. 2361 - 2363
(2007/10/03)
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- Multicomponent synthesis of novel amino acid-nucleobase chimeras: aA versatile approach to PNA-monomers
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This paper describes a multicomponent approach to novel totally protected precursors of PNA-monomers via Ugi 4CC. The obtained bisamides are converted into several partially protected PNA-monomers or derivatives thereof using three different procedures. Methods for hydrolysis are shown to be dependent on the nature of the isocyano component required for Ugi 4CC. Several novel monomers suitable for oligomer synthesis are prepared demonstrating the high versatility of the reaction sequence. Copyright (C) 2000 Elsevier Science Ltd.
- Maison, Wolfgang,Schlemminger, Imre,Westerhoff, Ole,Martens, Juergen
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p. 1343 - 1360
(2007/10/03)
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- Dehydration of formamides using the Burgess Reagent: A new route to isocyanides
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The Burgess Reagent readily converts formamides into isocyanides in high yields and is particularly effective for substrates containing halide sensitive trimethylsilyl ether groups.
- Creedon, Siobhan M.,Crowley, H. Kevin,McCarthy, Daniel G.
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p. 1015 - 1017
(2007/10/03)
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- Postcondensation modifications of Ugi four-component condensation products: 1-Isocyanocyclohexene as a convertible isocyanide. Mechanism of conversion, synthesis of diverse structures, and demonstration of resin capture
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The concept of a 'universal isocyanide' that enables postcondensation modification of Ugi four-component condensation products is introduced. This strategy is suited for the synthesis of libraries. By using 1-isocyanocyclohexene as the isocyanide input in the Ugi reaction, the product cyclohexenamides can be converted to a variety of products. From the original α-(acylamino) amides, new carboxylic acids, esters, and thioesters are produced from acid-activated conversion of the cyclohexenamide moiety. It has been determined that the intermediate in conversion of this type is an oxazolinium-5-one (munchnone) that reacts with many nucleophiles to yield the products above. The munchnone can also undergo cycloaddition with acetylenic dipolarophiles to form pyrroles. Through internal nucleophilic attack, Ugi products are shown to convert to a protected monosaccharide derivative and to 1,4-benzodiazepine-2,5-diones. All of the conversions described consist of a single step. Resin capture of Ugi products is demonstrated, in which a solution condensation reaction is followed by trapping of the products onto solid support resin. Both the trapping step and subsequent cleavage of products from the resin occur in very high yield.
- Keating,Armstrong
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p. 2574 - 2583
(2007/10/03)
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- The Preparation of Epoxy Isonitriles (Isocyanooxiranes)
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The preparation of epoxy isonitriles from vinyl formaides using an epoxidation/ dehydration sequence is described.
- Baldwin, J. E.,ONeil, I. A.
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p. 2047 - 2050
(2007/10/02)
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- REDUCTIVE FORMYLATION OF OXIMES; AN APPROACH TO THE SYNTHESIS OF VINIL ISONITRILES
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Reduction of ketoximes using anhydrous titanium-(III)-acetate in the presence of mixed formic-acetic anhydride yields N-formyl enamines whichmay be dehydrate to vinyl isonitriles
- Barton, H. R. Derek,Bowles, Timothy,Husinec, Suren,Forbes, Judith E.,Llobera, Antonia,et al.
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p. 3343 - 3346
(2007/10/02)
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