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CN-122011039-A - Large-steric-hindrance triazole carbene monodentate palladium compound containing surplus N, N chelating ligand, and preparation method and application thereof

CN122011039ACN 122011039 ACN122011039 ACN 122011039ACN-122011039-A

Abstract

The invention discloses a large steric hindrance triazole carbene monodentate palladium compound containing a surplus N, N chelating ligand and shown in a structural formula I, and a preparation method and application thereof, wherein the preparation method comprises the steps of (1) adding a compound S and a compound Ar into an organic solvent, reacting for 12-24 hours at 80-120 ℃, and purifying to obtain a large steric hindrance triazole salt L containing the surplus N, N chelating ligand; and (2) adding the L, the palladium salt and the alkali into an organic solvent, stirring for 6-12 hours at 50-90 ℃, purifying and drying to obtain the target product. Compared with the traditional carbene palladium compound, the triazole carbene monodentate palladium compound containing the rich N, N chelating ligand has stronger electron donating capability, and the N heterocyclic carbene skeleton contains a pair of rich coordination points, so that the N, N chelating ligand can stably combine with a palladium center and simultaneously coordinate with metallic copper through the rich coordination points, and the C-H bond arylation reaction of the bimetallic high-efficiency synergistic catalytic oxazole derivative is realized.

Inventors

  • HU TAIYONG
  • RUAN XING
  • CHEN HONGRUN
  • WANG HAONAN
  • SONG HENG
  • CAI XINGWEI
  • XU CHEN

Assignees

  • 江苏科技大学

Dates

Publication Date
20260512
Application Date
20260120

Claims (10)

  1. 1. A large steric hindrance triazole carbene monodentate palladium compound containing a surplus N, N chelating ligand is characterized by having the structural formula: ; Wherein n=0 or 1;R 1 is hydrogen, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 haloalkyl, phenyl or halogen, R 2 is hydrogen or C1-C3 alkyl, R 3 is C1-C5 alkyl, C1-C3 alkylphenyl, halogen, X is halogen.
  2. 2. The sterically bulky triazocarbene monodentate palladium compound containing a redundant N, N chelating ligand as defined in claim 1, wherein said R 2 is hydrogen or methyl.
  3. 3. The sterically bulky triazocarbene monodentate palladium compound containing a redundant N, N chelating ligand as set forth in claim 1, wherein X is Cl, br or I.
  4. 4. The sterically bulky triazocarbene monodentate palladium compound containing a redundant N, N chelating ligand as set forth in claim 1, wherein the sterically bulky triazocarbene monodentate palladium compound of a redundant N, N chelating ligand has the structural formula: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 Or (b) 。
  5. 5. A method for preparing the large-steric-hindrance triazole carbene monodentate palladium compound containing a surplus N, N chelating ligand according to any one of claims 1 to 4, which is characterized by comprising the following steps: (1) Adding a compound S and a compound Ar into an organic solvent, reacting for 12-24 hours at 80-120 ℃, and purifying to obtain a large steric hindrance triazole salt L containing a surplus (N, N) chelating ligand; (2) Adding the large steric hindrance triazole salt L containing the surplus (N, N) chelating ligand, palladium salt and alkali into an organic solvent, stirring for 6-12 hours at 50-90 ℃, purifying and drying to obtain the large steric hindrance triazole carbene monodentate palladium compound containing the surplus N, N chelating ligand, wherein the synthetic route is as follows: 。
  6. 6. The method for producing a sterically bulky triazazole carbene monodentate palladium compound containing a surplus N, N chelating ligand as defined in claim 5, wherein in step (2), the molar ratio of the sterically bulky triazazole salt, palladium salt and base of the surplus (N, N) -chelating ligand is 1:0.5 to 1:1 to 3.
  7. 7. The method for producing a sterically bulky triazocarbene monodentate palladium compound containing a redundant N, N chelating ligand as set forth in claim 5, wherein in step (2), said organic solvent is acetonitrile, tetrahydrofuran or 1, 4-dioxane.
  8. 8. The method for producing a sterically bulky triazocarbene monodentate palladium compound containing a redundant N, N chelating ligand as set forth in claim 5, wherein in step (2), said palladium salt is palladium acetate, palladium chloride or palladium bromide.
  9. 9. Use of a sterically bulky triazazole carbene monodentate palladium compound containing a redundant N, N chelating ligand as defined in any one of claims 1 to 4 in the C-H bond arylation reaction of oxazole derivatives.
  10. 10. The application of the method according to claim 9, wherein the application method comprises the steps of adding bromoarene, oxazole derivatives, alkali, copper salt and a large steric-hindrance triazole carbene monodentate palladium compound containing a surplus of N, N chelating ligand into an organic solvent for reaction for 12-24 hours at 80-100 ℃, and obtaining an arylation product of the oxazole derivatives, wherein the synthetic route is as follows: ; Wherein R 1 is methyl, phenyl, pyridyl, naphthyl, ethyl formate or triphenylamine, R 2 is hydrogen, methyl, ethyl, methoxy, aldehyde, hydroxy, benzyl hydroxy, phenyl, cyano, nitro, hydroxyethyl or acetyl, and Z is carbon or nitrogen.

Description

Large-steric-hindrance triazole carbene monodentate palladium compound containing surplus N, N chelating ligand, and preparation method and application thereof Technical Field The invention relates to a compound and a preparation method and application thereof, in particular to a triazole carbene monodentate palladium compound with high steric hindrance and containing a surplus N, N chelating ligand, and a preparation method and application thereof. Background The aromatic (heteroaromatic) group substituted oxazole is taken as an important structural unit, widely exists in various natural products, and has important application value in the fields of medicinal chemistry, organic functional materials and the like. Among the various methods of synthesizing aromatic (heteroaromatic) substituted oxazoles available, the c—h bond direct aromatic (heteroaromatic) alkylation reaction is advantageous because it has a high atomic economy and does not require complex pre-metallization. However, such reactions often require multiple catalysts and ligands to co-catalyze and higher reaction temperatures in practice, such as those shown below: ; 。 Reaction 1 (org. Lett. 2021, 23, 1996-2001) requires co-catalysis with palladium acetate, cuprous bromide and two phosphine ligands, and reaction 2 (chem. Commun., 2024, 60, 13931-13934) requires the use of about 10% mmol of palladium-copper alloy, with the reaction being completed at an elevated temperature of 120 ℃. In recent years, the N-heterocyclic carbene compound is widely studied due to the advantages of simple preparation, high stability and the like, but the existing researches are mostly focused on a single metal-N-heterocyclic carbene complex system, and the complex has poor effect in catalyzing the C-H bond arylation reaction of an oxazole derivative. Disclosure of Invention The invention aims to provide a large-steric-hindrance triazole carbene monodentate palladium compound containing a surplus N, N chelating ligand, which can efficiently and selectively catalyze C-H bond arylation reaction of an oxazole derivative, a preparation method of the large-steric-hindrance triazole carbene monodentate palladium compound containing the surplus N, N chelating ligand, and an application of the large-steric-hindrance triazole carbene monodentate palladium compound containing the surplus N, N chelating ligand. The technical scheme is that the large-steric-hindrance triazole carbene monodentate palladium compound containing the surplus N, N chelating ligand has the structural formula: ; Wherein n=0 or 1;R 1 is hydrogen, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 haloalkyl, phenyl or halogen, R 2 is hydrogen or C1-C3 alkyl, R 3 is C1-C5 alkyl, C1-C3 alkylphenyl, halogen, X is halogen. Preferably, R 2 is hydrogen or methyl. Preferably, X is Cl, br or I. Preferably, the structural formula of the large-steric-hindrance triazole carbene monodentate palladium compound of the spare N, N chelating ligand is as follows: 、、、、、、、、、、、、、、、、、、、 Or (b) 。 The preparation method of the triazole carbene monodentate palladium compound containing the residual N, N chelating ligand with large steric hindrance comprises the following steps: (1) Adding a compound S and a compound Ar into an organic solvent, reacting for 12-24 hours at 80-120 ℃, and purifying to obtain a large steric hindrance triazole salt L containing a surplus (N, N) chelating ligand; (2) Adding the large steric hindrance triazole salt L containing the surplus (N, N) chelating ligand, palladium salt and alkali into an organic solvent, stirring for 6-12 hours at 50-90 ℃, purifying and drying to obtain the large steric hindrance triazole carbene monodentate palladium compound containing the surplus N, N chelating ligand, wherein the synthetic route is as follows: 。 preferably, in step (1), the organic solvent is tetrahydrofuran or 1, 4-dioxane. Preferably, in the step (2), the molar ratio of the triazole salt, palladium salt and alkali containing the residual (N, N) chelating ligand is 1:0.5-1:1-3. Preferably, in step (2), the organic solvent is acetonitrile, tetrahydrofuran or 1, 4-dioxane. Preferably, in the step (2), the palladium salt is palladium acetate, palladium chloride or palladium bromide. Preferably, in step (2), the base is potassium hydroxide, sodium hydroxide or potassium tert-butoxide. The invention relates to an application of a large steric hindrance triazole carbene monodentate palladium compound containing a surplus N, N chelating ligand in the C-H bond arylation reaction of an oxazole derivative. The synthesis method of the compound S refers to papers, namely synthesis and characterization of a bidentate azacyclo-carbene monovalent copper compound and photophysical property research [ D ]. MaTeng Jiangsu university of technology, 2023, and the synthetic route is as follows: 。 Preferably, the application method comprises the steps of adding bromoarene, an oxazole derivative, alkali, copper salt and a large-steric-hindrance