Copper-catalyzed CuAAC/intramolecular C–H arylation sequence: Synthesis of annulated 1,2,3-triazoles

• Rajkumar Jeyachandran,
• Harish Kumar Potukuchi and
• Lutz Ackermann

Beilstein J. Org. Chem. 2012, 8, 1771–1777, doi:10.3762/bjoc.8.202

• -economical syntheses of annulated 1,2,3-triazoles were accomplished through copper-catalyzed intramolecular direct arylations in sustainable one-pot reactions. Thus, catalyzed cascade reactions involving [3 + 2]-azide–alkyne cycloadditions (CuAAC) and C–H bond functionalizations provided direct access to

• for direct arylations of 1,2,3-triazoles. Thus, we showed that intermolecular copper-catalyzed C–H bond functionalizations could be combined with the Huisgen [51] copper(I)-catalyzed [52][53] [3 + 2]-azide–alkyne cycloaddition (CuAAC)[54], while C–H bond arylations of 1,2,3-triazoles were previously

• consisting of copper(I)-catalyzed [3 + 2]-azide–alkyne cycloadditions (CuAAC) and intramolecular C–H bond arylations. Notably, the optimized copper catalyst accelerated two mechanistically distinct transformations, which set the stage for the formation of up to one C–C and three C–N bonds in a chemo- and

Antifreeze glycopeptide diastereomers

• Lilly Nagel,
• Carsten Budke,
• Axel Dreyer,
• Thomas Koop and
• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1657–1667, doi:10.3762/bjoc.8.190

• proline replacements [5]. These peptides exhibit less antifreeze activity than monosaccharide-substituted AFGP analogues without proline residues. Peptoid glycoconjugates with carbohydrate moieties attached by CuI catalyzed azide-alkyne cycloaddition (CuAAC) were devoid of antifreeze activity [17

Parallel solid-phase synthesis of diaryltriazoles

• Matthias Wrobel,
• Jeffrey Aubé and
• Burkhard König

Beilstein J. Org. Chem. 2012, 8, 1027–1036, doi:10.3762/bjoc.8.115

• predictability of their potency and selectivity as inhibitors is still limited. We have recently reported the synthesis of triazole-based α-helix mimetics 3 and 4 [16], which are efficiently available through azide–alkyne cycloadditions [17]. We now report the use of this chemistry to prepare libraries of

• example of a more complex alkyne. The azide–alkyne [3 + 2] cycloaddition was catalyzed with copper(II) sulfate pentahydrate and L-ascorbic acid in DMF overnight at room temperature. A solution of EDTA was added to remove the remaining copper cations from the resin. Resin cleavage under acidic conditions

High-affinity multivalent wheat germ agglutinin ligands by one-pot click reaction

• Henning S. G. Beckmann,
• Heiko M. Möller and
• Valentin Wittmann

Beilstein J. Org. Chem. 2012, 8, 819–826, doi:10.3762/bjoc.8.91

• conveniently prepared by employing a one-pot procedure for Cu(II)-catalyzed diazo transfer and Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) starting from commercially available amines. These glycoclusters were probed for their binding potencies to the plant lectin wheat germ agglutinin (WGA) from

• ligands. In this report, we describe the preparation of such a series of multivalent WGA ligands by a one-pot procedure for diazo transfer and azide–alkyne cycloaddition [48] starting from commercially available di- and triamines and the propargyl glycoside of N,N’-diacetylchitobiose. Binding potencies

• scaffolds [52][53][54]. Recently, we reported a convenient one-pot procedure for diazo transfer and azide–alkyne cycloaddition [48] giving access to multivalent triazole-linked structures starting from amines. For the synthesis of triazole-linked glycoclusters, commercially available amines A1–A6 (Figure 1

Synthetic glycopeptides and glycoproteins with applications in biological research

• Ulrika Westerlind

Beilstein J. Org. Chem. 2012, 8, 804–818, doi:10.3762/bjoc.8.90

• resistant to tumor growth compared to control mice [37]. Vaccines with multivalent MUC1 T- and TN-glycopeptides were efficiently conjugated through azide/alkyne click chemistry to the Pam3CSK4 lipopeptide immune-stimulant. The recently reported vaccines are currently under immunological investigation [38

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

• Yagang Zhang and
• Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

• % yield. Alternatively, azobenzene dye 16 underwent a room-temperature copper-catalyzed azide–alkyne Huisgen cycloaddition with DeUG alkyne 17 to give triazole 18 in 71% yield. Azobenzene coupled DAN modules 5, 8, and 10 are bright orange–red in color, and azobenzene coupled DeUG modules 12 and 18 are

• EDC and DMAP in methylene chloride, and the orange–yellow product 12 was isolated in a relatively low 35% yield (Scheme 3). No attempt was made to optimize the coupling conditions; instead, attention was turned to the possibility of coupling the partners by using the copper-catalyzed azide–alkyne

• produced crude 16, which was used directly in the next step without purification. Coupling of azide 16 with the known 17 [34] was successfully effected under standard conditions for the copper-catalyzed azide–alkyne cycloaddition [55]. Azobenzene dye-coupled DeUG module 18 was obtained as an orange–yellow

Synthesis of 2-amino-3-arylpropan-1-ols and 1-(2,3-diaminopropyl)-1,2,3-triazoles and evaluation of their antimalarial activity

• Matthias D’hooghe,
• Stéphanie Vandekerckhove,
• Karen Mollet,
• Karel Vervisch,
• Stijn Dekeukeleire,
• Liesbeth Lehoucq,
• Carmen Lategan,
• Peter J. Smith,
• Kelly Chibale and
• Norbert De Kimpe

Beilstein J. Org. Chem. 2011, 7, 1745–1752, doi:10.3762/bjoc.7.205

• )methyl]aziridines by Cu(I)-catalyzed azide-alkyne cycloaddition, followed by microwave-assisted, regioselective ring opening by dialkylamine towards 1-(2,3-diaminopropyl)-1,2,3-triazoles. Although most of these compounds exhibited weak antiplasmodial activity, six representatives showed moderate

• 1,2,3-triazole moiety instead. A powerful methodology towards the synthesis of functionalized 1,2,3-triazoles involves the Cu(I)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAC) [33], which has gained major interest from the synthetic community due to its high efficiency and selectivity. Eligible

• -triazol-1-yl)methyl]aziridines by Cu(I)-catalyzed azide-alkyne cycloaddition, followed by microwave-assisted, regioselective ring opening by diethyl- or dimethylamine towards the corresponding 1-(2,3-diaminopropyl)-1,2,3-triazoles. From a synthetic viewpoint, new insights were provided concerning the

Highly efficient cyclosarin degradation mediated by a β-cyclodextrin derivative containing an oxime-derived substituent

• Michael Zengerle,
• Florian Brandhuber,
• Christian Schneider,
• Franz Worek,
• Georg Reiter and
• Stefan Kubik

Beilstein J. Org. Chem. 2011, 7, 1543–1554, doi:10.3762/bjoc.7.182

• with 2-formylpyridine oxime or 2-acetylpyridine oxime, unfortunately failed to produce the desired products. The cyclodextrin derivatives 2a–d contain 1,4-disubstituted 1,2,3-triazole moieties as the linking units. Accordingly, they were prepared by copper(I)-catalyzed azide–alkyne cycloaddition

• (“click-reaction”) [33] from mono-6-azido-6-deoxy-β-cyclodextrin (4) and a functionalized alkyne (Scheme 3, route B). Conjugations by copper(I)-catalyzed azide–alkyne cycloadditions have become popular in many different fields of chemistry [33][34], including cyclodextrin chemistry [35][36][37][38][39][40

Advances in synthetic approach to and antifungal activity of triazoles

• Kumari Shalini,
• Nitin Kumar,
• Sushma Drabu and
• Pramod Kumar Sharma

Beilstein J. Org. Chem. 2011, 7, 668–677, doi:10.3762/bjoc.7.79

• nitrogen atoms. However, flash vacuum pyrolysis at 500 °C leads to loss of molecular nitrogen (N2) to produce aziridine. Certain triazoles are relatively easy to cleave by ring–chain tautomerism. Synthesis of triazoles Substituted 1,2,3-triazoles can be produced by the azide–alkyne Huisgen cycloaddition in

• ). Itraconazole (10). Voriconazole (11). Posaconazole (12). Ravuconazole (13). Copper catalyzed azide–alkyne cycloaddition. Ruthenium catalyzed azide–alkyne cycloaddition. Copper-sulfate catalyzed azide–alkyne cycloaddition. Azide–dimethylbut-2-yne-dioate cycloaddition.

Synthesis of glycoconjugate fragments of mycobacterial phosphatidylinositol mannosides and lipomannan

• Benjamin Cao,
• Jonathan M. White and
• Spencer J. Williams

Beilstein J. Org. Chem. 2011, 7, 369–377, doi:10.3762/bjoc.7.47

• ) lipophilicity allowing biphasic partitioning between butanol/water or purification by reversed-phase extraction, (ii) ability to be reduced to an aminooctyl chain for use in squarate conjugation chemistry, and (iii) capacity to be conjugated with fluorescent terminal alkynes using the Cu(I)-catalyzed azide

• –alkyne cycloaddition (CuAAC) reaction [33][34]. Results and Discussion Since their introduction by Palcic and co-workers [35], hydrophobic alkyl glycosides have proven to be valuable derivatives for enzymatic assays, as their lipophilic nature allows easy product isolation by either reversed-phase

Synthesis and crossover reaction of TEMPO containing block copolymer via ROMP

• Olubummo Adekunle,
• Susanne Tanner and
• Wolfgang H. Binder

Beilstein J. Org. Chem. 2010, 6, No. 59, doi:10.3762/bjoc.6.59

• ™). However, their synthetic profile with respect to the synthesis of block copolymers is largely unexplored. As we recently have reported extensively on the use of ROMP methods in blockcopolymer synthesis [11][12][13], either via direct copolymerization or coupled to postmodification methods via azide/alkyne