Tetradentate ligand containing nitrogen and oxygen and preparation method thereof

A tetradentate ligand, chirality technology, applied in the direction of organic chemistry, can solve the problem of less research, and achieve the effect of simple raw materials, few steps, and high yield

Inactive Publication Date: 2019-11-01
JIANGSU UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most of the nitrogen- and oxygen-containing chiral ligands used in asymmetric catalytic reactions are bidentate or tridentate ligands, while nitrogen- and oxygen-containing tetradentate chiral ligands are relatively less studied in this field.

Method used

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  • Tetradentate ligand containing nitrogen and oxygen and preparation method thereof
  • Tetradentate ligand containing nitrogen and oxygen and preparation method thereof
  • Tetradentate ligand containing nitrogen and oxygen and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Formula I compound: nitrogen-containing, oxygen-containing tetradentate ligand preparation, the specific steps are as follows:

[0024] (1) Add pyridoxal (5mmol) to a 50mL round bottom flask, then add 5mL absolute ethanol, after the pyridoxal is completely dissolved, add (R,R)-cyclohexanediamine (2.5mmol) ethanol dropwise (5mL) solution, react at room temperature for 6h, filter with suction, recrystallize with 95% ethanol to obtain chiral pyridoxal bis-imine, dry in vacuum for later use.

[0025] (2) Add metal reducing agent iron powder (0.34g, 6mmol) and anhydrous THF 10mL in a 50mL three-necked flask, under nitrogen protection, slowly inject TiCl under stirring at room temperature 4 (0.7mL, 6mmol), the mixture was refluxed for 2h, cooled to room temperature, and the pH value of the system was adjusted to 3-4 with triethylamine to obtain a black paste low-valent titanium reagent. At room temperature and under the protection of nitrogen, a solution of chiral pyridoxa...

Embodiment 2-5

[0028] Only the metal reducing agent used in the preparation of the low-valent titanium reagent in step (1) of Example 1 is changed, and all the other are the same as in Example 1. The yield of the metal reducing agent used and the target product containing nitrogen and oxygen tetradentate ligands is shown in Table 1 Shown:

[0029] Table 1

[0030]

Embodiment 6-8

[0032] Only change the carbonyl reagent used in embodiment 1 step (2), all the other are the same as embodiment 1, the productive rate of carbonyl reagent used and target product nitrogen-containing, oxygen tetradentate ligand is as shown in table 2:

[0033] Table 2

[0034]

[0035] It can be seen that although both acetone and DMF contain carbonyl groups, when used in this reaction system, the effect is not ideal, resulting in a lower yield of the target product.

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Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a tetradentate ligand containing nitrogen and oxygen and a preparation method thereof. The tetradentate ligand containing nitrogen and oxygen has a structure as shown in a formula I. The preparation method comprises the following steps: firstly, preparing chiral pyridoxal diimine with pyridoxal as a rawmaterial; and performing a reaction with carbonyl reagents such as diethyl carbonate and the like under the action of a low-valent titanium reagent to prepare a target product, namely, the chiral nitrogen and oxygen-containing tetradentate ligand. The method has high yield and stereoselectivity, and has the advantages of easily available raw materials, few reaction steps, short reaction time, mildreaction conditions, convenient post-treatment and the like.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a nitrogen- and oxygen-containing tetradentate ligand and a preparation method thereof. Background technique [0002] Asymmetric synthesis, that is, the selective synthesis of enantiomerically pure compounds, is the frontier of chiral technology research. Asymmetric chiral catalysis has become one of the most important methods in chiral technology due to its outstanding advantages of chiral value-added. Among them, the research and development of new chiral ligands has always been a hot and difficult point in the field of asymmetric catalytic reactions. In 2001, the Royal Swiss Academy of Sciences awarded the Nobel Prize in Chemistry to Knowles of the United States, Noyori of Japan and Sharpless of the United States in recognition of their outstanding contributions in the field of asymmetric catalytic reactions. These three Nobel Prize winners have all desi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D498/22
CPCC07D498/22
Inventor 林伟庄苍伟胡秀秀梁国斌杨凤丽
Owner JIANGSU UNIV OF TECH
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