Preparation method of 4-(2,5-dibromobenzoyl) aza-aromatic ring

A technology for dibromobenzoyl and azaaromatic rings, which is applied in the field of preparation of 4-azaaromatic rings, can solve problems such as difficult bromination reactions and decreased reactivity of benzene rings, and achieve stable and feasible processes, good quality, The effect of high product yield

Inactive Publication Date: 2019-11-22
CHENGDU UNIV
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Problems solved by technology

At present, there are few reports on the preparation methods of 4-(2,5-dibromobenzoyl) azaaromatic rings, and the literature (Rajamalli, P,; Senthilkumar, N.; Gandeepan, P.; J.Am.Chem.Soc. 2016,138,628) was prepared by brominating 4-benzoylpyridine. Due to the decrease in the reactivity of the benzene ring substituted by the pyridineformyl group, it brings difficulties to the bromination reaction, and may lead to single bromine substitution, indeterminate position Polybrominated substitution by-products produced

Method used

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  • Preparation method of 4-(2,5-dibromobenzoyl) aza-aromatic ring
  • Preparation method of 4-(2,5-dibromobenzoyl) aza-aromatic ring
  • Preparation method of 4-(2,5-dibromobenzoyl) aza-aromatic ring

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Embodiment 1

[0024] The preparation of the hydrochloride of embodiment 1 4-pyridinecarbonyl chloride

[0025] Dissolve 12.3 grams of 4-pyridinecarboxylic acid in 50 mL of dioxane, add 14.5 mL of thionyl chloride, add 5 drops of N, N-dimethylformamide, heat to 105 ° C, react for four hours, evaporate the solvent and di Thionyl chloride was obtained as off-white solid, cooled, filtered, the filter cake was washed with petroleum ether, the solid was collected, dried under reduced pressure to obtain 16.8 g of product, yield: 94.9%.

Embodiment 2

[0026] Example 2 Preparation of 4-(2,5-dibromobenzoyl)pyridine

[0027] Under ice-bath conditions, 17.7 grams of 4-pyridineformyl chloride hydrochloride prepared according to Example 1, 26.6 grams of aluminum trichloride, and 58.5 grams of 1,4-dibromobenzene were mixed and stirred for 30 minutes, and the temperature was raised to 100 ° C. The reaction was completed in 2 hours. Pour the reactant into ice water, stir to decompose the complex, extract three times with dichloromethane, combine the organic layers, wash with water, wash with saturated sodium chloride, and dry over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure, and the residue was brownish yellow. After cooling, crystals were formed, and recrystallized with a mixed solvent of ethyl acetate and petroleum ether (2:1) to obtain light yellow transparent crystals, which were dried under reduced pressure to obtain 25.3 g of the product, yield: 75.1%.

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Abstract

The invention discloses a preparation method of a 4-(2, 5-dibromobenzoyl) aza-aromatic ring. The method comprises the following steps: 1, performing a reaction on aza-aromatic ring formic acid with achlorinating agent according to a certain feeding ratio in a weak polar solvent system to prepare aza-aromatic ring formyl chloride hydrochloride, wherein the process has advantages of reducing the consumption of the chlorinating agent and relieving the environmental pollution caused by the chlorinating agent; and 2, carrying out a Lewis acid catalytic reaction on the aza-aromatic ring formyl chloride hydrochloride and 1,4-dibromobenzene in a certain feeding ratio at a certain temperature in a solvent-free system to obtain the 4-(2,5-dibromobenzoyl) aza-aromatic ring.

Description

technical field [0001] The application belongs to the technical field of fine chemical synthesis, in particular, it relates to a preparation method of 4-(2,5-dibromobenzoyl)azaaryl ring. Background technique [0002] The third-generation organic electroluminescent (OLED) materials are thermally activated delayed fluorescence (TADF) molecules, and TADF materials with benzoyl structures such as 4-(2,5-dicarbazolebenzoyl) azaaromatic rings are expected to As an excellent OLED material, the 4-(2,5-dibromobenzoyl) azaaryl ring is the key intermediate for the synthesis of benzoyl-type TADF molecules. The molecular structure is shown below. [0003] [0004] Wherein X1-X5 each independently represents an N atom or a C atom, and X1-X5 has at least one N atom. [0005] At the same time, aryl ketone is a common structural unit in the drug structure, and 4-(2,5-dibromobenzoyl) nitrogen heteroaromatic ring may also become a pharmaceutical intermediate. At present, there are few rep...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/50C07D241/12C07D239/26
CPCC07D213/50C07D239/26C07D241/12
Inventor 甘亚何钢胡建平
Owner CHENGDU UNIV
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