Unlock instant, AI-driven research and patent intelligence for your innovation.

A kind of preparation method of PEG immobilized chiral bisoxazoline ligand

A bisoxazoline and ligand technology is applied in the field of preparation of PEG-immobilized chiral bisoxazoline ligands, and can solve the problem of low yield of synthesizing azabisoxazoline ligands, no recycling of catalysts, and single The problem of high cost of methyl ether, to achieve the effect of improving the solid loading rate and stability, high activity and stereoselectivity, and low production cost

Active Publication Date: 2019-04-30
TSINGHUA UNIV
View PDF3 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In 2000, Reiser et al. connected the soluble polymer polyethylene glycol monomethyl ether MeOPEG-5000 to the heterobisoxazoline ligand to obtain the immobilized chiral ligand, and then combined it with Cu(OTf) 2 Coordination catalyzed the cyclopropanation reaction of styrene and methyl diazoacetate, the enantioselectivity was 91% (trans), better than the non-immobilized effect (87%, trans), and the yield was 69%, and the The catalyst can be recycled up to 9 times, and the catalyst activity and enantioselectivity are not significantly reduced; however, the yield of the synthetic azabisoxazoline ligand is low, and the cost of grafting to the derivatized PEG-5000 monomethyl ether Higher, lower replacement rate
In 2002, Cozzi et al. obtained the ligand through a complex synthetic route and grafted it to derivatized PEG-5000 monomethyl ether to obtain an immobilized chiral ligand, and then coordinated it with CuOTf to catalyze the synthesis of styrene and Cyclopropanation of ethyl diazoacetate with 91% (trans) enantioselectivity and 63% yield, but the catalyst is not well recycled
How to develop and prepare high activity, high selectivity and good stability in a simple way, reusable immobilized chiral bisoxazoline catalysts is still a challenging and valuable problem

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A kind of preparation method of PEG immobilized chiral bisoxazoline ligand
  • A kind of preparation method of PEG immobilized chiral bisoxazoline ligand
  • A kind of preparation method of PEG immobilized chiral bisoxazoline ligand

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Synthesis

[0036] (1) Preparation of OMs-PEG-2000

[0037] Dissolve 20g of PEG-2000 in 400ml of toluene solution, raise the temperature to remove water, protect with nitrogen, and distill out 100ml / g of toluene. Cool down to room temperature, add 20ml of dichloromethane and 3.46ml of triethylamine, stir for 15min, then add 2.3ml of methanesulfonyl chloride, and stir at room temperature for 18h. After the reaction is over, add 5ml of methanol, stir for 30min, and use G 2 Floxacin funnel + diatomaceous earth filtration, after the filtrate was concentrated under reduced pressure, 300ml of isopropanol was added to dissolve and clear, precipitated in an ice-water bath, filtered through a Buchner funnel, rinsed with 50ml of ether, and dried in vacuo to obtain 18.6g of OMs-modified 2(OMs- The HPLC-ELSD spectrum of PEG-2000 is as follows Figure 4 ), the yield was 93%.

[0038]

[0039] (2) Preparation of I-PEG-2000

[0040] Add 10 g of 2 in step (1), 100 ml of aceto...

Embodiment 2

[0047] With embodiment 1, just change PEG-2000 into PEG-4000.

[0048] (1) Dissolve 20g of PEG-4000 in 400ml of toluene solution, raise the temperature to remove water, protect with nitrogen, and distill out 100ml of toluene. Cool down to room temperature, add 20ml of dichloromethane and 1.73ml of triethylamine, stir for 15min, then add 1.15ml of methanesulfonyl chloride and stir at room temperature for 18h. After the reaction is over, add 5ml of methanol, stir for 30min, and use G 2 Filtrate through a sand star funnel + diatomaceous earth, concentrate the filtrate under reduced pressure, add 300ml of isopropanol to dissolve it and clear it, and precipitate in an ice-water bath. Filtered with a Buchner funnel, rinsed with 50ml of ether, and dried in vacuo to obtain 19.0g of OMs-PEG-4000 with a yield of 95%.

[0049] (2) Add 15g of OMs-PEG-4000 in step (1) and 150ml of acetone to a 500ml single-necked bottle, stir to dissolve, add 2.23g of sodium iodide, and reflux for 18h. ...

Embodiment 3

[0052] Same as Example 1, except that PEG-2000 is changed to MeOPEG-10K.

[0053] (1) Dissolve 20g of MeOPEG-10K in 400ml of toluene solution, raise the temperature to remove water, protect with nitrogen, and distill 100ml of toluene. Cool down to room temperature, add 30ml of dichloromethane and 0.35ml of triethylamine, stir for 15min, then add 0.23ml of methanesulfonyl chloride and stir at room temperature for 18h. After the reaction is over, add 5ml of methanol, stir for 30min, and use G 2 Filtrate through the Floxacin funnel + diatomaceous earth, concentrate the filtrate under reduced pressure, add 350ml of isopropanol to dissolve it and clear it, and precipitate in an ice-water bath. Filtrate through a Buchner funnel, rinse with 50 ml of ether, and dry in vacuo to obtain 18.0 g with a yield of 90%.

[0054] (2) Add 18g of OMs-MeOPEG-10K in step (1) and 200ml of acetone to a 500ml single-necked bottle, stir to dissolve, add 0.54g of sodium iodide, and reflux for 18h. Co...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention belongs to the technical field of organic synthesis and catalysis, and particularly relates to a PEG (polyethylene glycol) immobilized chiral bisoxazoline ligand preparation method. The preparation method includes the steps: firstly, reacting PEG with methylsufonyl chloride to obtain OMs-PEG; secondly, refluxing the OMs-PEG and sodium iodide in acetone to obtain iodo-PEG; grafting chiral bisoxazoline ligand with the iodo-PEG under the action of n-butyllithium to obtain PEG immobilized chiral bisoxazoline ligand. The immobilization rate and stability of active groups are effectively improved, PEG carriers can be dissolved in a reaction solvent to form a homogeneous phase reaction system, functions of a catalyst and a substrate are facilitated, electronic effects of the ligand are achieved, activity and stereo-selectivity of the ligand are higher, diethyl ether is added after reaction, the catalyst can be simply and conveniently separated from the reaction system and reused, the chiral bisoxazoline ligand is inexpensive, easy to obtain, wide in applicability and high in activity, the preparation process is simple, high in yield and low in production cost, environmental pollution is avoided, and solid-liquid separation of the catalyst and an intermediate product can be realized by a conventional method.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis and catalysis, and in particular relates to a preparation method of PEG immobilized chiral bisoxazoline ligands. Background technique [0002] The asymmetric cyclopropanation reaction of styrene and EDA can obtain important chiral intermediates for the synthesis of pyrethroid pesticides. Studies on catalyzing such reactions have been successfully reported, and the most studied ones are on chiral bisoxazolines. Chiral bisoxazolines are a class of compounds that are readily available and widely used. Since the 1980s, the reactions catalyzed by bisoxazoline ligands include: asymmetric allyl substitution reaction, allyl oxidation reaction, cyclopropanation reaction of alkenes and imines, Diels-Alder reaction, free radical addition Synthesis reaction, Makaiyama aldol reaction, nucleophilic addition reaction of imine and aldehyde, hydrosilylation reduction reaction, etc. In order to improve...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C08G65/334C08G65/337C08G65/333B01J31/22C07C67/343C07C69/747
CPCB01J31/2217B01J2531/0213B01J2531/0241B01J2531/16C07C67/343C08G65/33396C08G65/3346C08G65/337C07C69/747
Inventor 何海晓吕阳成
Owner TSINGHUA UNIV