Synthesis of N -unsubstituted 1,2,3-triazoles via aerobic oxidative N -dealkylation using copper(II) acetate

Cha, Hyojin; Lee, Kyongkyu; Yoon, Dae

doi:10.1016/j.tet.2017.03.068

Cited by 20 publications

(6 citation statements)

References 43 publications

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“… 19 The CuAAC variant of this reaction is not readily performed, and methods based on transiently protected azides have been developed. To enable this reaction under the CuAAC reaction protocol and to avoid handling hazardous hydrazoic acid, N -protected organic azides, such as azidomethyl pivalate, azidomethyl morpholine-4-carboxylate, azidomethyl N , N -diethylcarbamate, 20 trimethylsilyl azide, 21 and α-azidoacetophenone, 22 were demonstrated as viable substrates for the stepwise synthesis of 4-substituted-1 H -1,2,3-triazoles via CuAAC, followed by a deprotection sequence. In the case of the trimethylsilyl azide reaction, TMS- N 1 -protected triazoles were not isolated, suggesting that hydrazoic acid may be involved in the reaction as a reactive species.…”

Section: Introductionmentioning

confidence: 99%

Copper-Catalyzed Azide–Alkyne Cycloaddition of Hydrazoic Acid Formed In Situ from Sodium Azide Affords 4-Monosubstituted-1,2,3-Triazoles

2022

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We report a copper-catalyzed cycloaddition of hydrogen azide (hydrazoic acid, HN 3 ) with terminal alkynes to form 4-substituted-1 H -1,2,3-triazoles in a sustainable manner. Hydrazoic acid was formed in situ from sodium azide under acidic conditions to react with terminal alkynes in a copper-catalyzed reaction. Using polydentate N-donor chelating ligands and mild organic acids, the reactions were realized to proceed at room temperature under aerobic conditions in a methanol–water mixture and with 5 mol % catalyst loadings to afford 4-substituted-1,2,3-triazoles in high yields. This method is amenable on a wide range of alkyne substrates, including unprotected peptides, showing diverse functional group tolerance. It is applicable for late-stage functionalization synthetic strategies, as demonstrated in the synthesis of the triazole analogue of losartan. The preparation of orthogonally protected azahistidine from Fmoc- l -propargylglycine was realized on a gram scale. The hazardous nature of hydrazoic acid has been diminished as it forms in situ in <6% concentrations at which it is safe to handle. Reactions of distilled solutions of hydrazoic acid indicated its role as a reactive species in the copper-catalyzed reaction.

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Section: Introductionmentioning

confidence: 99%

Copper-Catalyzed Azide–Alkyne Cycloaddition of Hydrazoic Acid Formed In Situ from Sodium Azide Affords 4-Monosubstituted-1,2,3-Triazoles

2022

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“…(°C) Refs. 1 H H 5a 93 166–167 [ 58 ] 2 OMe H 5b 89 190–191 [ 58 ] 3 H Br 5c 86 145–146 [ 59 ] 4 H NO 2 5d 77 180–181 [ 60 ] 5 H Cl 5e 89 150–152 [ 59 ] 6 H OMe 5f 88 142–143 [ 59 ] 7 CF 3 H 5g 81 221–223 [ 58 ] 8 Me H 5h 85 165–167 [ 58 ] Phenacyl bromides (1 mmol), arylacetylene (1.2 mmol), K 2 CO 3 ...…”

Section: Resultsmentioning

confidence: 99%

Peanut shell as a green biomolecule support for anchoring Cu2O: a biocatalyst for green synthesis of 1,2,3-triazoles under ultrasonic irradiation

et al. 2019

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Cu 2 O supported on peanut shell (Cu 2 O@PS) was prepared by the reaction of copper acetate and peanut shell powder as a naturally available biopolymer support. The prepared catalyst was used as an efficient and reusable heterogeneous catalyst in the click reaction of benzyl halide or phenacyl bromides, acetylenes and sodium azide for the synthesis of potentially biologically active 1,2,3-triazoles under ultrasonic irradiation in EtOH-H 2 O as green solvent. Electronic supplementary material The online version of this article (10.1186/s13065-019-0612-9) contains supplementary material, which is available to authorized users.

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“…[70] Yoon and co-workers reported a chemoselective synthesis of 4-substituted-NH-1,2,3-triazoles 178 via copper-catalyzed aerobic oxidative reaction of β-ketotriazoles derivatives 175 (Scheme 35c). [71] The reaction was initiated with copper(I) catalyzed [3 + 2]cycloaddition reaction between an alkyne and α-azidoketones 1. The β-ketotriazole 175 undergoes CÀ N bond cleavage under aerobic oxidation in presence of copper(II) acetate as catalyst to obtain 178.…”

Section: Triazolesmentioning

confidence: 99%

Recent Advances onα‐Azidoketones and Esters in the Synthesis ofN‐Heterocycles

Maurya

Borkotoky

2022

Asian J Org Chem

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Organic azides have been proven to possess versatile reactivity that is utilized to synthesize a large number of molecular scaffolds. Among the azides, α‐azidoketones and esters have been widely explored to synthesize numerous high valued N‐heterocycles. The enhanced acidity of the methylene hydrogen atoms by adjacent carbonyl or ester groups of α‐azidoketones and esters largely attributes to their unique chemical behaviour. It has been mostly utilized in two ways: a) the azides have been directly treated with other reagents in a basic medium and b) they are converted into α‐azidovinylketones and esters through Knoevenagel condensation with aldehydes and subsequently treated with various reagents to access nitrogen heterocycles. This review provides a general outlook and concise report on α‐azidoketones and esters towards the synthesis of various N‐heterocycles such as pyrroles, indoles, pyrazoles, imidazoles, triazoles, pyridines, pyrimidine, pyrazine and many others.

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Synthesis of N -unsubstituted 1,2,3-triazoles via aerobic oxidative N -dealkylation using copper(II) acetate

Cited by 20 publications

References 43 publications

Copper-Catalyzed Azide–Alkyne Cycloaddition of Hydrazoic Acid Formed In Situ from Sodium Azide Affords 4-Monosubstituted-1,2,3-Triazoles

Copper-Catalyzed Azide–Alkyne Cycloaddition of Hydrazoic Acid Formed In Situ from Sodium Azide Affords 4-Monosubstituted-1,2,3-Triazoles

Peanut shell as a green biomolecule support for anchoring Cu2O: a biocatalyst for green synthesis of 1,2,3-triazoles under ultrasonic irradiation

Recent Advances onα‐Azidoketones and Esters in the Synthesis ofN‐Heterocycles

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