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Method for synthesizing 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid and alkyl ester thereof

A technology for the synthesis of alkyl and synthetic routes, which is applied in the field of synthesis of 6-fluoro-3,4-dihydro-2H-1-chromene-2-carboxylic acid and its alkyl esters, and can solve the problem of long steps problems, to achieve the effect of mild conditions, high yield and easy access to raw materials

Active Publication Date: 2013-10-30
上海立科化学科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This route has longer steps

Method used

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  • Method for synthesizing 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid and alkyl ester thereof
  • Method for synthesizing 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid and alkyl ester thereof
  • Method for synthesizing 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid and alkyl ester thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0047]

[0048] Red phosphorus (4.8 g, 0.16 mol) was dissolved in gamma-butyrolactone (600.0 g, 6.96 mol). Heat and stir to raise the temperature to 100° C., and start to add liquid bromine (1124.0 g, 7.00 mol) dropwise. After the completion of the reaction was tracked by GC, the system was cooled to 10°C in an ice bath, and 1200 mL of methanol and 4 mL of concentrated sulfuric acid were added. Stir overnight at room temperature. The pH value of the system was adjusted to neutral with saturated sodium bicarbonate solution, and dichloromethane was added for extraction. The organic phase was dried by adding anhydrous sodium sulfate. Distillation after filtration gave the product 2,4-dibromobutyric acid methyl ester as 1400.0 g of light yellow liquid with a purity of 99.4% and a yield of 76.9%.

Embodiment 2

[0050]

[0051]Red phosphorus (4.8 g, 0.16 mol) was dissolved in gamma-butyrolactone (600.0 g, 6.96 mol). Heat and stir to raise the temperature to 100° C., and start to add liquid bromine (1124.0 g, 7.00 mol) dropwise. After the completion of the reaction was tracked by GC, the system was cooled to 10°C in an ice bath, and 1200 mL of ethanol and 4 mL of concentrated sulfuric acid were added. Stir overnight at room temperature. The pH value of the system was adjusted to neutral with saturated sodium bicarbonate solution, and dichloromethane was added for extraction. The organic phase was dried by adding anhydrous sodium sulfate. Distillation after filtration gave the product ethyl 2,4-dibromobutyrate as 1470.0 g of light yellow liquid with a purity of 99.1% and a yield of 76.4%.

Embodiment 3

[0053]

[0054] Sodium hydride (90.0 g, 2.25 mol) was dissolved in 1500 mL of benzene, and p-fluorophenol (224.0 g, 2.00 mol) was slowly added. Stir overnight at 40°C. The methyl 2,4-dibromobutyrate obtained in Example 1 was dissolved in 1500 mL of benzene, and the temperature was raised to 60°C. Slowly drop in the previously prepared sodium p-fluorophenolate solution and stir for 5 hours. Suction filtration, the filtrate was washed with water, and dried by adding anhydrous sodium sulfate. After filtration, distillation gave the product 4-bromo-2-(4-fluorophenoxy)butanoic acid methyl ester, which was 476.0 g of a colorless liquid, with a purity of 93.6% and a yield of 81.0%. 1 H-NMR (DCCl 3 , 500Hz): 7.01-6.96(m, 4H), 4.85(t, J=10, 1H), 4.51-4.46(m, 1H), 4.35-4.296(m, 1H), 3.75(s, 3H), 2.71 -2.64(m, 1H), 2.48-2.40(m, 1H).

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Abstract

The invention relates to a method for synthesizing 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid and alkyl ester thereof. 2,4-dibromoalkylbutyrate is used as a raw material, and the products are obtained by three-step reaction. According to the synthesizing method, the 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid and the alkyl ester thereof serving as target products are obtained without hydrogenation reduction of expensive Pd / C catalyst; and the reaction process is simple, the conditions are mild, the raw materials are easily obtained, and the yield is high.

Description

technical field [0001] The invention relates to a new synthesis process of a key intermediate of cardiovascular drugs, 6-fluoro-3,4-dihydro-2H-1-chromene-2-carboxylic acid and its alkyl ester. Background technique [0002] 6-fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid is a key intermediate in the synthesis of cardiovascular drug nebivolol. Nebivolol is a selective β1-adrenoceptor antagonist with vasodilator activity developed by Johnson & Johnson. It was first launched in Germany in May 1997. [0003] Most of the reported 3,4-dihydro-2H-1-benzopyran-2-carboxylic acid synthesis method is to first synthesize 4-oxo-3,4-dihydro-2H-1-benzopyran furan-2-carboxylic acid, followed by Pd / C-catalyzed hydrogenation reduction. [0004] It is described in EP264586 that 4-oxo-1-benzopyran can be used as raw material, and after bromination, dehydrobromination, nitrile group and hydrolysis, 4-oxo-2H-1-benzopyran- 2-Carboxylic acid. The disadvantage of this route is that the re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D311/66
Inventor 郄骊陈清泉曾志宏
Owner 上海立科化学科技有限公司
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