Method for acetylating catalytic hydroxyl

A technology for catalyzing hydroxyacetylation and acetylation, applied in chemical instruments and methods, preparation of esterified saccharides, organic compounds, etc., can solve the problems of expensive reagents, harsh reaction conditions, long reaction time, etc., and achieve a green and friendly reaction. , the effect of short reaction time and simple preparation process

Inactive Publication Date: 2012-03-28
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the catalysts mentioned above have been applied in laboratory scale and even in industrialized production, there are still defects such as long reaction time, harsh reaction conditions, expensive reagents, poisonous and harmful, etc.

Method used

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  • Method for acetylating catalytic hydroxyl
  • Method for acetylating catalytic hydroxyl
  • Method for acetylating catalytic hydroxyl

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Embodiment 1, preparation of ionic liquid [HDBU]OAc, carry out the following steps successively:

[0030] Add 7.6g (50mmol) DBU into a 50mL three-neck flask, add an ice-water bath, and start magnetic stirring. Measure 3.0 g (50 mmol) of glacial acetic acid, transfer it to a constant-pressure dropping funnel, and slowly drop it into a flask while keeping the reaction temperature below 5°C (controlled at 0-5°C). After the addition of glacial acetic acid was completed, the ice-water bath was removed, and the reaction was stirred at room temperature for 24 h. The obtained oily reactant was vacuum-dried at 60° C. for 24 h to obtain a light yellow viscous liquid, namely Lewis base ionic liquid [HDBU]OAc, which was stored in a desiccator.

[0031] Its structural formula is as follows:

[0032]

Embodiment 2

[0033] Embodiment 2, a method for hydroxyacetylation catalyzed by a Lewis alkali ionic liquid (that is, a method for catalyzing hydroxyacetylation), using Lewis alkali ionic liquid [HDBU]OAc as a catalyst, the following steps are carried out successively:

[0034] 4-Nitrophenol (1.39g, 10mmol) and freshly distilled acetic anhydride (1.03g, 10.1mmol) were added to a 25mL flask equipped with a spherical condenser, followed by the catalyst [HDBU]OAc (0.42g, 2mmol, i.e. 20% molar ratio), turn on magnetic stirring, and slowly heat up to 50°C. The progress of the reaction was monitored by TLC (developing solvent: EtOAc / hexanes=1:4, V / V) and GC. After 45min, the conversion of 4-nitrophenol was completed. Add 20mL of diethyl ether to dilute the reaction solution, and filter to separate the upper product. 3 After washing the solution with 10 mL of water, add 0.5 g of anhydrous Na 2 SO 4 Drying, rotary evaporation under reduced pressure (0.02MPa) to remove diethyl ether yielded 1.72g...

Embodiment 3

[0035] Embodiment 3, a kind of hydroxyacetylation method catalyzed by Lewis alkali ionic liquid, take Lewis alkali ionic liquid [HDBU]OAc as catalyst, carry out the following steps successively:

[0036] Phenol (0.94 g, 10 mmol) and freshly distilled acetic anhydride (1.03 g, 10.1 mmol) were added to a 25 mL flask equipped with a spherical condenser, followed by the catalyst [HDBU]OAc (0.42 g, i.e. 20% molar ratio) , turn on the magnetic stirring, and slowly raise the temperature to 50°C. The progress of the reaction was monitored by TLC (developing solvent: EtOAc / hexanes=1:4, V / V) and GC. After 45min, the conversion of phenol was completed, and 20mL of diethyl ether was added to dilute the reaction solution, filtered, and the upper product was separated, and the obtained organic phase (that is, the upper layer extract containing the product) was successively washed with 10mL saturated NaHCO 3 After washing the solution with 10 mL of water, add 0.5 g of anhydrous Na 2 SO 4 ...

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Abstract

The invention discloses a method for acetylating catalytic hydroxyl, which comprises the following steps: using alcohol or phenol as a substrate, in the acetylating reaction of the alcohol or the phenol, using a Lewis alkaline ionic liquid [HDBU]OAc as a catalyst and acetic anhydride as an acetylating reagent, and carrying out a reaction in a solvent-free condition, wherein the reaction temperature is 40-80 DEG C, the reaction time is 0.75-3.0 hours, the mole ratio of the acetic anhydride to the substrate is 1.0-6.0: 1, and the mole ratio of the Lewis alkaline ionic liquid [HDBU]OAc to the substrate is 10%-30%; after the reaction is completed, adding diethyl ether, filtering, washing upper-layer extracting liquid in sequence by using a saturated NaHCO3 solution and water, adding anhydrousNa2SO4 to dry the upper-layer extracting liquid, and carrying out decompression rotary steaming on the dried upper-layer extracting liquid to remove the diethyl ether, so as to obtain a product. The method for acetylating the catalytic hydroxyl, which is provided by the invention, has the characteristics of moderate reaction condition, high yield and low cost, and the like, and the method is green and safe.

Description

technical field [0001] The invention relates to an organic synthesis method, in particular to a hydroxyl acetylation reaction catalyzed by Lewis base ionic liquid [HDBU]OAc. Background technique [0002] Acetylation reaction is one of the most common reactions in organic synthesis, and acetyl group is also a commonly used protecting group in complex synthetic reactions. According to literature reports, the acetylation protection of hydroxyl groups in alcohols and phenolic compounds is often carried out by acetyl chloride or acetic anhydride under acid or base catalysis, wherein pyridine, 4-dimethylaminopyridine (DMAP) and 4-pyrrole Pyridine (PPY) etc. are all good basic catalysts. In addition, acidic catalysts such as protonic acids (such as p-toluenesulfonic acid), Lewis acids (such as transition metal halides, trifluoromethanesulfonates, perchlorates) and solid acids (such as molecular sieves, etc.) can also catalyze hydroxyacetylation. reaction. Although the catalysts ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07B41/12B01J31/04C07C69/157C07C69/63C07C69/16C07C69/14C07C69/145C07C69/18C07C67/08C07C205/43C07C201/12C07H13/06C07H1/00
Inventor 陈新志计立钱超
Owner ZHEJIANG UNIV
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