Search results

Search for "Ugi reaction" in Full Text gives 63 result(s) in Beilstein Journal of Organic Chemistry.

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

  • Gijs Koopmanschap,
  • Eelco Ruijter and
  • Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

Graphical Abstract
  • (PADAM) strategy was reported for the first time by Banfi and co-workers in 2003 [23]. In addition, subsequent oxidation of 7 gives access to α-keto amides 8 that show important protease inhibitory activities. The Ugi reaction One of the most important MCRs that generates peptide-like structures was
  • 3-CR, the Ugi 4-CR is favoured in polar protic solvents like low-molecular weight alcohols such as methanol, ethanol or trifluoroethanol. However, many examples in polar aprotic solvents are also reported. The generally accepted mechanism for the Ugi reaction proceeds via in situ imine formation of
  • -formation of the imine or the use of bifunctional inputs (e.g. amino acids) can reduce this Ugi-4CR to an Ugi-3CR. In particular, the Ugi reaction with bifunctional inputs is called an Ugi-four-center-three-component reaction (U-4C-3CR) and has been extensively applied in peptidomimetic synthesis [21][22
PDF
Album
Review
Published 04 Mar 2014

Diversity-oriented synthesis of dihydrobenzoxazepinones by coupling the Ugi multicomponent reaction with a Mitsunobu cyclization

  • Lisa Moni,
  • Luca Banfi,
  • Andrea Basso,
  • Alice Brambilla and
  • Renata Riva

Beilstein J. Org. Chem. 2014, 10, 209–212, doi:10.3762/bjoc.10.16

Graphical Abstract
  • derivatives. Keywords: benzoxazepines; diversity-oriented synthesis; multicomponent reactions; Mitsunobu reaction; Ugi reaction; Introduction Although the classical Ugi 4-component reaction (U-4CR) leads to acyclic peptide-like compounds, post-condensation cyclizations can afford a huge variety of drug-like
  • triphenylphosphine oxide. We eventually found that the easiest and most efficient protocol involved reduction with Me3P, followed by evaporation of the solvent and by subsequent Ugi reaction on the crude. With Me3P, phosphazene hydrolysis was much faster and the phosphine oxide was much more easily separated by
  • operationally simple protocol opens a straightforward route to 2,3-dihydrobenzo[f][1,4]oxazepin-3-ones 10 starting from 2-(benzyloxy)benzyl azides, in turn accessible from variously substituted salicylic aldehydes or acids. We were able to use directly the azides as input in the Ugi reaction without the need to
PDF
Album
Supp Info
Letter
Published 17 Jan 2014

Synthesis and biological activity of N-substituted-tetrahydro-γ-carbolines containing peptide residues

  • Nadezhda V. Sokolova,
  • Valentine G. Nenajdenko,
  • Vladimir B. Sokolov,
  • Daria V. Vinogradova,
  • Elena F. Shevtsova,
  • Ludmila G. Dubova and
  • Sergey O. Bachurin

Beilstein J. Org. Chem. 2014, 10, 155–162, doi:10.3762/bjoc.10.13

Graphical Abstract
  • chiral centre of the isocyanoazide does not occur under the conditions of the Ugi reaction [20]. This approach permits to prepare a broad variety of azidopeptides using multicomponent methodology. The modification of N-substituted tetrahydro-γ-carbolines 3a–d by peptide fragments was performed using Cu(I
  • added to the residue. After evaporation of the solvent the corresponding dihydrochlorides 7a–g were obtained. Structures of dimebon and SS peptides. Synthesis of starting N-substituted tetrahydro-γ-carbolines 3a–d. Synthesis of peptides 5 through the Ugi reaction. Synthesis of N-substituted tetrahydro-γ
PDF
Album
Supp Info
Full Research Paper
Published 15 Jan 2014

The multicomponent approach to N-methyl peptides: total synthesis of antibacterial (–)-viridic acid and analogues

  • Ricardo A. W. Neves Filho,
  • Sebastian Stark,
  • Bernhard Westermann and
  • Ludger A. Wessjohann

Beilstein J. Org. Chem. 2012, 8, 2085–2090, doi:10.3762/bjoc.8.234

Graphical Abstract
  • ; toxin; Ugi reaction; Introduction Viridic acid (1) is a tetrapeptide produced by several fungi of the genus Penicillium, including P. viridicatum, P. nordicum, and P. aurantiogriseum among others [1][2][3][4]. It was first isolated from the basic fraction of the chloroform/methanol extract of P
  • substance (Scheme 2) [5]. In order to more rapidly access derivatives for biological activity screens, we decided to investigate the suitability of a MCR approach utilizing the Ugi reaction. Due to the character of the Ugi-4CR, the racemate of viridic acid and congeners is easily available, and assaying
PDF
Album
Supp Info
Video
Full Research Paper
Published 28 Nov 2012

Synthetic studies towards bottromycin

  • Stefanie Ackermann,
  • Hans-Georg Lerchen,
  • Dieter Häbich,
  • Angelika Ullrich and
  • Uli Kazmaier

Beilstein J. Org. Chem. 2012, 8, 1652–1656, doi:10.3762/bjoc.8.189

Graphical Abstract
  • thiopeptide 3 [37], easily obtained by thio-Ugi reaction in excellent yield. The reaction was very fast and was finished already after 15 min, and peptide 3 crystallized directly from the reaction mixture. Because our first attempts to couple 3 directly with amines to the corresponding amidine 5 failed [43
  • subjected to a thio-Ugi reaction as described before, and the expected sterically highly demanding endothiopeptide 8 was obtained in high yield as a 1:1 diastereomeric mixture. In this case, the diastereomers could not be separated. Elongation of the peptide chain under standard peptide coupling conditions
  • intramolecular fashion. The intramolecular approach allows the synthesis of the bottromycin ring system in a straightforward manner. The synthesis of the bottromycins and derivatives thereof is currently under investigation. Bottromycins. Syntheses of endothiopeptides by thio-Ugi reaction. Synthesis of amidine 5
PDF
Album
Supp Info
Full Research Paper
Published 01 Oct 2012

Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

  • Hiroki Oguri,
  • Haruki Mizoguchi,
  • Hideaki Oikawa,
  • Aki Ishiyama,
  • Masato Iwatsuki,
  • Kazuhiko Otoguro and
  • Satoshi Ōmura

Beilstein J. Org. Chem. 2012, 8, 930–940, doi:10.3762/bjoc.8.105

Graphical Abstract
  • (Scheme 3). According to the previously reported protocol [22], Ugi reaction employing allylamine (31) and stepwise installation of a diazoimide group provided 35 in good yield. Upon treatment of 35 with Rh2(OAc)4 in benzene under reflux, 1,3-dipolar cycloaddition of the ylide intermediate with the
PDF
Album
Supp Info
Full Research Paper
Published 22 Jun 2012

Synthesis of (−)-julocrotine and a diversity oriented Ugi-approach to analogues and probes

  • Ricardo A. W. Neves Filho,
  • Bernhard Westermann and
  • Ludger A. Wessjohann

Beilstein J. Org. Chem. 2011, 7, 1504–1507, doi:10.3762/bjoc.7.175

Graphical Abstract
  • heterocyclic precursor as an amino input in Ugi four-component reactions (Ugi-4CR) [1]. Keywords: diversity oriented synthesis; julocrotine; leishmania; Mitsunobu reaction; Ugi reaction; Introduction Julocrotine (1) is a natural glutarimide alkaloid isolated from several plants of the genus Croton [2][3][4
PDF
Album
Supp Info
Full Research Paper
Published 07 Nov 2011

Ugi post-condensation copper-triggered oxidative cascade towards pyrazoles

  • Aurélie Dos Santos,
  • Laurent El Kaim,
  • Laurence Grimaud and
  • Caroline Ronsseray

Beilstein J. Org. Chem. 2011, 7, 1310–1314, doi:10.3762/bjoc.7.153

Graphical Abstract
  • ; isocyanide; pyrazolidinone; Introduction In the last twenty years, the Ugi reaction coupled with its various post-condensations towards heterocyclic libraries has established the success of isocyanide-based multicomponent reactions [1][2][3][4][5][6][7]. Chemists in both academia and industry have taken
  • these optimized conditions. Results are reported in Table 1. Surprisingly, the reaction appears to be only efficient with Ugi adducts prepared with formaldehyde as the carbonyl component (Table 1, entries 1–5). With other aldehydes and ketones, even if the Ugi reaction was performed easily, the
  • following cyclization failed to give the expected pyrazolidinones and resulted in complex mixture formation. Intermediate Ugi adduct 3g (Table 1, entry 6) only resulted in a small amount of ring-opened product 4g. The reaction is also limited to N-aryl hydrazones due to the lower efficiency of the Ugi
PDF
Album
Supp Info
Letter
Published 21 Sep 2011

A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions

  • Ameer F. Zahoor,
  • Sarah Thies and
  • Uli Kazmaier

Beilstein J. Org. Chem. 2011, 7, 1299–1303, doi:10.3762/bjoc.7.151

Graphical Abstract
  • powerful tool for the synthesis of acylated α-hydroxyacid amides [10]. Later on, in 1961, Ugi and Steinbrückner reported the extension of this protocol by incorporating also a primary amine as a fourth component [11]. Therefore, the Ugi reaction is even more flexible than the Passerini approach, but both
  • reactions together have made the IMCR highly popular in combinatorial chemistry [7][8]. Our group has been involved in amino acid and peptide synthesis for nearly two decades [12][13], and multicomponent reactions are known to play a dominant role [14][15]. In particular, the Ugi reaction has so far been
  • peptide-derived drugs. Attempts to improve the yields and to evaluate the scope and limitations are currently underway. Passerini reactions of α,β-unsaturated aldehyde 5. Passerini and Ugi reaction of saturated aldehyde 7. Synthesis of γ-oxo-amino acids. Passerini reactions of γ-oxo-amino acids
PDF
Album
Supp Info
Full Research Paper
Published 19 Sep 2011

Multicomponent synthesis of artificial nucleases and their RNase and DNase activity

  • Anton V. Gulevich,
  • Lyudmila S. Koroleva,
  • Olga V. Morozova,
  • Valentina N. Bakhvalova,
  • Vladimir N. Silnikov and
  • Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2011, 7, 1135–1140, doi:10.3762/bjoc.7.131

Graphical Abstract
  • Abstract The synthesis of new, artificial ribonucleases containing two amino acid residues connected by an aliphatic linker has been developed. Target molecules were synthesized via a catalytic three-component Ugi reaction from aliphatic diisocyanides. Preliminary investigations proved unspecific nuclease
  • , containing two amide bonds and variable substituents, can be synthesized by the Ugi reaction with subsequent removal of diamine residue (Scheme 1). Original substrates for the synthesis could be aliphatic diisocyanides 3, amines (with an easily removable protective group) and aldehydes. We used an
  • organocatalytic three-component modification of the Ugi reaction, recently developed by List et al. [25]. The reaction results in diamines 4, thus avoiding the acid residue removal stage. The starting diisocyanides 3 were obtained in good overall yields from commercially available diamines containing 6, 7, 8, 10
PDF
Album
Supp Info
Full Research Paper
Published 19 Aug 2011

Novel synthesis of pseudopeptides bearing a difluoromethyl group by Ugi reaction and desulfanylation

  • Jingjing Wu,
  • Hui Li and
  • Song Cao

Beilstein J. Org. Chem. 2011, 7, 1070–1074, doi:10.3762/bjoc.7.123

Graphical Abstract
  • Jingjing Wu Hui Li Song Cao Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China 10.3762/bjoc.7.123 Abstract Thirteen difluoromethyl-containing pseudopeptides were synthesized by Ugi reaction using the novel
  • cleavage; Ugi reaction; Introduction Fluorinated amino acids and pseudopeptides have increasingly attracted attention in recent years [1][2][3][4][5]. The selective incorporation of fluorine-containing groups, such as trifluoromethyl, difluoromethyl and difluoromethylene, into peptides or peptidomimetics
  • continuation of our interest in the synthesis of diverse difluoromethyl-containing pseudopeptides, we herein report a novel and efficient synthesis of difluoromethyl-containing pseudopeptides through Ugi reaction, with gem-difluoromethylene-containing acid as a key component, followed by reductive cleavage of
PDF
Album
Supp Info
Full Research Paper
Published 08 Aug 2011

Long-range diastereoselectivity in Ugi reactions of 2-substituted dihydrobenzoxazepines

  • Luca Banfi,
  • Andrea Basso,
  • Valentina Cerulli,
  • Valeria Rocca and
  • Renata Riva

Beilstein J. Org. Chem. 2011, 7, 976–979, doi:10.3762/bjoc.7.109

Graphical Abstract
  • Luca Banfi Andrea Basso Valentina Cerulli Valeria Rocca Renata Riva Department of Chemistry and Industrial Chemistry, University of Genova, I-16146 Genova, Italy 10.3762/bjoc.7.109 Abstract The Ugi reaction of 2-substituted dihydrobenzoxazepines was found to proceed with unexpectedly good
  • diastereoselectivitiy (diastereoisomeric ratios up to 9:1), despite the large distance between the pre-existing stereogenic centre and the newly generated one. This result represents the first good 1,4 asymmetric induction in an Ugi reaction as well as the first example of diastereoselective Ugi reaction of seven
  • membered cyclic imines. It allows the diversity-oriented synthesis of various tetrahydro[f][1,4]benzoxazepines. Keywords: benzoxazepines; cyclic imines; long range stereoinduction; multicomponent reactions; Ugi reaction; Introduction The Ugi reaction is probably the most renowned and widely used
PDF
Album
Supp Info
Letter
Published 13 Jul 2011

Synthesis of dihydrophenanthridines by a sequence of Ugi-4CR and palladium- catalyzed intramolecular C-H functionalization

  • Florence Bonnaterre,
  • Michèle Bois-Choussy and
  • Jieping Zhu

Beilstein J. Org. Chem. 2008, 4, No. 10, doi:10.3762/bjoc.4.10

Graphical Abstract
  • -functionalization reaction has proven to be an efficient strategy to increase the skeleton diversity. Results The Ugi reaction of an o-iodobenzaldehyde (2), an aniline (3), an isocyanide (4), and a carboxylic acid (5) afforded α-acetamido-α-phenylacetamide (6) in good to excellent yields. The palladium-catalyzed
  • summarized in Table 2. 4-Nitroaniline (3c) is known to be inactive in Ugi reaction due to the reduced nucleophilicity of the nitrogen and the low basicity of the resulting imine leading consequently to a low concentration of the iminium ion. However, by performing the reaction in trifluoroethanol (TFE) [35
PDF
Album
Supp Info
Full Research Paper
Published 08 Apr 2008
Other Beilstein-Institut Open Science Activities