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Chirality pyridine double-oxazoline catalyzer and method for preparing the same and application thereof

A pyridinebisoxazoline, catalyst technology, applied in catalyst activation/preparation, chemical instruments and methods, physical/chemical process catalysts, etc., can solve the problem of low activity and enantioselectivity, high enantioselectivity, Harsh reaction conditions and other problems, to achieve the effect of improving enantioselectivity

Inactive Publication Date: 2008-02-06
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The present invention overcomes the shortcomings of the existing pyridine bisoxazoline ligands in DA reactions with relatively low activity and enantioselectivity, or high enantioselectivity but harsh reaction conditions, through the deployment of electronic effects and steric effects Some new ligands were designed and synthesized and used in asymmetric DA reactions. The activity of the catalyst and the enantioselectivity of the product were significantly higher than the current ones under milder reaction conditions (0°C to 25°C). Literature report

Method used

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  • Chirality pyridine double-oxazoline catalyzer and method for preparing the same and application thereof
  • Chirality pyridine double-oxazoline catalyzer and method for preparing the same and application thereof
  • Chirality pyridine double-oxazoline catalyzer and method for preparing the same and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] 4-Chloro-2,6-bis[4'(S)-tert-butyloxazoline-2'-]pyridine Synthesis

[0037] One drop of N,N-dimethylformamide was added to letronine (2.1 mmol, 422.1 mg), followed by the addition of thionyl chloride SOCl 2 11ml, reflux for 24h. Excess thionyl chloride was concentrated under reduced pressure.

[0038] Add 9ml of chloroform to (S)-tert-leucinol (4.3mmol, 503.9mg), cool to 0°C, add triethylamine (12.9mmol, 1.7ml), then add 15ml of acid chloride in chloroform, and stir at room temperature for one hour Days later, with 5% HCl and saturated NaHCO 3 Wash, anhydrous Na 2 SO 4 After drying and concentration, it was directly used in the next reaction. Add 20ml of chloroform to the concentrated substance, and directly add thionyl chloride SOCl 2 5.4ml, the mixture was refluxed for 9h, concentrated under reduced pressure, and purified by column chromatography (ethyl acetate / petroleum ether=1:4) to obtain 480mg of pure product with a yield of 52%.

[0039] Sodium hydride (...

Embodiment 2

[0041] 4-Bromo-2,6-bis[4'(S)-isopropyloxazoline-2'-]pyridine Synthesis

[0042] Phosphorus pentabromide (38.26mmol, 16.49mg) was added to leidronine (5.87mmol, 1.18g) and refluxed at 90°C for 3 hours. After the reaction was completed, it was lowered to room temperature, and 23ml of chloroform was added therein for dilution, and the resulting solution was filtered , the filtrate was cooled to 0°C, and then 33ml of methanol solution was slowly added dropwise to it, concentrated after the dropwise addition, and recrystallized in methanol to obtain 1.37g of crystalline 4-bromo-pyridine-2,6-dicarboxylic acid methyl ester, producing The rate is 85%.

[0043] Add 12ml of 5M aqueous sodium hydroxide solution to 4-bromo-pyridine-2,6-dicarboxylic acid methyl ester (2.50mmol, 685mg), reflux for 1 hour, and after cooling, the solution is acidified to pH=2, forming a white The precipitate was filtered and dried under vacuum at 60°C to obtain 584 mg of 4-bromo-pyridine-2,6-dicarboxylic a...

Embodiment 3

[0047] 4-Chloro-2,6-bis[4'(S)-benzyloxazoline-2'-]pyridine Synthesis

[0048] The synthetic method is the same as in Example 1, except that (S)-tert-leucinol is replaced by (S)-phenylalaninol, and finally 4-chloro-2,6-bis[4'(S)-benzyloxazoline The yield of -2'-]pyridine was 49%. 1 H NMR (400MHz, CDCl 3 )δ8.23(s, 2H), 7.34-7.22(m, 10H), 4.67-4.64(m, 2H), 4.47(t, J=8Hz, 2H), 4.26(t, J=8Hz, 2H), 3.28-3.23(m, 2H), 2.78-2.72(m, 2H); 13 C NMR (100 MHz, CDCl 3 )δ162.2, 148.3, 145.7, 137.8, 129.4, 128.9, 126.9, 126.2, 73.1, 68.4, 41.8; HRMS Calcd for C 25 h 22 N 3 o 2 Cl(M) 431.1401, found 431.1404.

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Abstract

A catalyst of chiral bis-oxazolinylpyridine is provided, which comprises two parts including a 4-z-2, 6-bis [4'(s)-R oxazoline-2'-] pyridine as the chiral ligand of the bis-oxazolinylpyridine, and a Scandate, Yttrium and Lanthanide metal salt. The preparation method is to mix the metal salt, the ligand of bis-oxazolinylpyridin with the equal molar quantity, and a 4-molecular sieve together, the mixture is added with the needed solvent, and then stirred under the temperature of -78 to 25 DEG C to obtain the catalyst prepared in situ. The usual dosage of the catalyst used for catalyzing Diels-Alder reaction is 1percent to 5percent of the dosage of the substrate. The catalyst can catalyze Diels-Alder reaction of both alpha, beta-unsaturated N-acetyl oxazolidone and alpha, beta-unsaturated ester with high efficiency in high selectivity. Under condition of the normal pressure with the temperature of 0 to 25 DEG C, the catalyst can accomplish the conversion rate as high as 100 percent and the enantiomeric selectivity of 96 percent.

Description

technical field [0001] The invention relates to a chiral pyridine bisoxazoline catalyst. [0002] The present invention also relates to a method for preparing the above-mentioned catalyst. [0003] The present invention also relates to the application of the above-mentioned catalyst in Diels-Alder reaction. Background technique [0004] Chiral synthesis is the frontier research direction of organic chemistry and catalytic chemistry. With the increasing proportion of chiral drugs in the market, it has attracted more and more attention. The Diels-Alder (DA) reaction is widely used in the synthesis of natural products and fine chemicals, and is an important method for the synthesis of six-membered cyclic compounds, which can form up to four chiral centers through a one-step reaction. Among many catalysts, the catalyst combined with chiral bisoxazoline ligand and Lewis acid shows good catalytic performance, and can obtain excellent enantioselectivity in DA reaction (Lewis Acid...

Claims

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Application Information

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IPC IPC(8): B01J31/02B01J23/10B01J37/00
Inventor 李灿王红
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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