Orthogonal functionalization of a fullerene building block through copper-catalyzed alkyne–azide and thiol–maleimide click reactions

In this study, the synthesis of an orthogonally clickable fullerene building block mono-adduct bearing on one side an alkyne unit and a maleimide moiety on the other side is presented. This derivative has been involved in CuAAC and thiol–maleimide click reactions using stepwise or one-pot processes with benzyl azide and 1-octanethiol. The one-pot process involving the CuAAC reaction followed by the thiol–maleimide conjugation gives the highest yield. This new platform could pave the way for the synthesis of a wide range of fullerene derivatives exploiting this set of orthogonal reactions.     

Synthesis,characterization and catalytic properties of a copper-containing polyoxovanadate nanocluster in azide–alkyne cycloaddition

A copper-containing polyoxovanadate nanocluster, [(C₂H₅)₄N]₄[V₈Cu₂O₂₄]?2H₂O (1), was synthesized through reaction between the Cu(NO₃)₂?3H₂O and [(C₂H₅)₄N]₄VO₃ in the molar ratio 1?:?4. Nanocluster 1 was characterized by IR, elemental analysis, XRD, SEM, TEM, and X-ray crystallography. The catalytic activity of 1 for the azide–alkyne cycloaddition of different terminal alkynes and organic azides generated in situ from sodium azide and different organic halides was tested. The protocol could afford the corresponding products in good to excellent yield at very low catalyst loadings (3.4 Mol%) under the optimized reaction conditions.     

An easy two step synthesis of macrocyclic peptidotriazoles via a four-component reaction and copper catalyzed intramolecular azide–alkyne [3+2] click cycloaddition

A two-step macrocyclization strategy for the synthesis of 12- and 14-membered cyclic peptidotriazoles by combining a one pot four-component reaction and an intramolecular [3+2] azide–alkyne click cycloaddition reaction is described. Macrocycles are obtained in good to excellent yield from the aqueous work-up of the reaction mixture and it is possible to expand or contract the ring size by adjusting the length of the nitrile moiety used in the MCR stage.     

One-pot synthesis of oxoisoindoline-1,2,3-triazole hybrid by a Ugi–click reaction

1,2,3-Triazole-3-oxoisoindoline-1-carboxamide system was successfully synthesized by using a combination of Ugi and click reactions. This two-step, one-pot synthesis was started by the reaction of 2-formyl benzoic acid, propargyl amine, and cyclohexyl isocyanide in ethanol. The resultant Ugi adduct underwent a copper-catalyzed click reaction, producing the desired products in good yields.     

Chain-growth polymerization of azide–alkyne difunctional monomer: Synthesis of star polymer with linear polytriazole arms from a core

This article reports a chain-growth coupling polymerization of AB difunctional monomer via copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction for synthesis of star polymers. Unlike our previously reported CuAAC polymerization of AB _n (n ≥ 2) monomers that spontaneously demonstrated a chain-growth mechanism in synthesis of hyperbranched polymer, the homopolymerization of AB monomer showed a common but less desired step-growth mechanism as the triazole groups aligned in a linear chain could not effectively confine the Cu catalyst in the polymer species. In contrast, the use of polytriazole-based core molecules that contained multiple azido groups successfully switched the polymerization of AB monomers into chain-growth mechanism and produced 3-arm star polymers and multi-arm hyperstar polymers with linear increase of polymer molecular weight with conversion and narrow molecular weight distribution, for example, M_w/M_n ~ 1.05. When acid-degradable hyperbranched polymeric core was used, the obtained hyperstar polymers could be easily degraded under acidic environment, producing linear degraded arms with defined polydispersity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 84–90     

Synthesis of new thioxanthenes by organocatalytic intramolecular Friedel–Crafts reaction

An efficient organocatalytic route has been developed to synthesize novel substituted thioxanthenes (2a–2v) starting from diaryl thioether alcohols (1a–1v) using the intramolecular Friedel–Crafts reaction. The starting materials were obtained in two stages via a coupling reaction followed by the Grignard reaction. In this study, we tried for the first time to use some organic Brønsted acids as organocatalysts (3a–3h) in the intramolecular Friedel–Crafts cyclization reaction of thioether alcohols. The synthesis of original substituted thioxanthenes was achieved within 15?minutes by using N-triflylphosphoramide (3h) with quantitative yields in THF at room temperature.     

In situ prepared CuI nanoparticles on modified poly(styrene-co-maleic anhydride): an efficient and recyclable catalyst for the azide–alkyne click reaction in water

A facile, high-yielding and straightforward methodology for the copper-catalyzed synthesis of 1,4-disubstituted 1,2,3-triazoles in water, using in situ prepared copper nanoparticles (NPs) on modified poly(styrene-co-maleic anhydride) [SMA] catalyst, is reported. The polymer support was easily prepared from the reaction of SMA with 4-aminopyridine and subsequently underwent reaction with CuI NPs. The catalyst was applied for the preparation of triazoles under air, followed by chromatographic separation of the products. The polymer-supported catalyst not only showed high catalytic activity but also showed high 1,4-regioselectivity for the [3 + 2] Huisgen cycloaddition in water as solvent. The products were obtained in good to excellent yields in all cases. The catalyst can be used without pre-activation and reloaded for at least five runs without significant decrease in its activity. The catalyst was characterized by SEM, energy dispersive spectroscopy analysis of X-rays, and inductively coupled plasma.     

Synthesis and click reaction of tubulin polymerization inhibitor 9-azido-α-noscapine

Research on Chemical Intermediates - An efficient protocol for the synthesis of tubulin polymerization inhibitor, 9-azido-α-noscapine 2h from 9-amino-α-noscapine 2g is developed using...     

Practical synthesis of 13C-labeled conjugates by [13C]CO-carbonylation of supported arylbipyridylpalladium complexes and alkyne–azide cycloadditions

A short procedure for the preparation of stable arylbipyridylpalladium complexes linked to a polystyrene resin is described. Starting from an o-iodobenzylalcohol with a pendant azido group, the corresponding supported complex was carbonylated with [¹³C]CO to produce the desired ¹³C-labeled lactone tag with a satisfactory yield of 50%. This ¹³C-synthon was obtained with excellent purity after a simple filtration on sintered glass, and further conjugation using CuAAC and SPAAC reactions was performed with model substrates.     

Synthesis,characterization, and investigation of catalytic activity of copper(II) porphyrin graphene oxide for azide–alkyne cycloaddition

Research on Chemical Intermediates - A covalently cross-linked graphene oxide (GO) catalyst was prepared by a cross-linking process using nucleophilic reaction of copper(II)‐coordinated...     

Synthesis of conjugates of closo-dodecaborate dianion with cholesterol using a “click” reaction

The nucleophilic ring-opening reaction of tetrahydropyran derivative of the closo-dode-caborate dianion with sodium azide in the presence of tetrabutylammonium bromide led to the novel azido-derivatives of[B₁₂H₁₂]^2?. A Cu-catalyzed 1,3-dipolar [3+2] cycloaddition reaction of the closo-dodecaborate dianion azido-derivatives with alkynyl-cholesterol led to 1,4-disubstituted 1,2,3-triazoles with the closo-dodecaborate fragment at position 1. The resulting conjugates are potentially suitable for the development of liposomal drugs to selectively deliver boron into a tumor cell for boron neutron capture therapy of cancer.

     

Iodine/CuI-mediated alkyne–carbonyl metathesis reaction: synthesis of 1-aryl-1,2-dihydrochromeno[2,3-b]azepine-3,6-dione

Iodine/cuprous iodide-mediated intramolecular alkyne–carbonyl metathesis reaction has been developed using 2-(N-aryl-N-propargyl)aminochromone-3-carbaldehyde as the substrate. It led to the synthesis of hitherto unreported chromeno[2,3-b]azepine-3,6-dione. The special features of this methodology are mild reaction conditions, 100% atom economy and use of inexpensive reagents. This is the first example of I₂/CuI-mediated alkyne–carbonyl metathesis reaction.     

Synthesis of RGD analogues containing α-Tfm-arginine as potential fibrinogen receptor antagonists

The synthesis of two peptide mimetics of RGD, α-Tfm-Arg-Gly-Asp-Phe-NH₂ 9 and α-Tfm-Arg-Gly-Asp-NH-(CH₂)₂-C₆H₅ 13, is described. The precursor of α-Tfm-ornithine was obtained in two synthetic steps from 2-N-Cbz-2-Tfm-hexanediacid-1-alkyl ester and introduced into the peptide chain by α-carboxy-group activation via oxazolone. The introduction of the guanidine residue led to the final peptides as mixtures of the two diastereomers. Configurationally pure peptides were obtained in good yields by RP-HPLC.     

Synthesis of β-substituted tetrahydrofurans by the prins reaction

Mixtures of 3-trif uoroacetoxy- and 3-chloro-4-alkyltetraliydrofurans were synthesized by the reaction of a series of-olefins with formaldehyde in trifuoroacetic acid and trimethylchlorosilane.The characteristics of the mixtures of cis and trans isomers are given, and the n_D ²⁰ values are given for the trans isomers.Bashkir State University, Institute of Fine Organic Synthesis. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 605–608, May, 1995. Original article submitted November 4, 1994; revision submitted May 10, 1995.     

Synthesis of pyrazolo[3,4-b]pyrrolo[3,4-d]pyridine derivatives via Aza-Diels–Alder reaction: evaluation of torsion effect of pyrazoylimines

A modified method for the synthesis of pyrazolo[3,4-b]pyrrolo[3,4-d]pyridine was developed through an Aza-Diels–Alder reaction of pyrazoylimines with maleimides in the sealed tube. Based on the control experiment, the yields for the Aza-Diels–Alder reaction seemed proportional to the suitable torsion conformation of pyrazoylimine, which was modulated by N,N-disubstituted amidinyl moiety. The versatile sealed tube technique was also proved to promote the higher isolated yields in the Aza-Diels–Alder reaction.     

Synthesis of hexahydroisoindole-3a-carboxylates by IMDA reaction of Morita–Baylis–Hillman adduct-derived dienes bearing a Z-alkenyl tether

An intramolecular Diels–Alder (IMDA) reaction of Morita–Baylis–Hillman adduct-derived dienes bearing a Z-alkenyl dienophile tether afforded hexahydroisoindole-3a-carboxylates in excellent yields and stereoselectivity.     

An one-pot approach to the synthesis of triazolobenzothiadiazepine 1,1-dioxide derivatives by basic alumina-supported azide–alkyne [3+2] cycloaddition

An efficient one-pot strategy for the synthesis of triazolobenzothiadiazepine 1,1-dioxide derivatives has been developed by the reaction of 2-azido-N-substituted benzenesulfonamides and propargyl bromide in basic alumina under microwave condition via [3+2] azide–alkyne cycloaddition reaction. This protocol has synthetic advantages in terms of low environmental impact and short reaction time.