Method for preparing 4-formoxylbenzofuran

A technology of dibromomethylbenzene and furazan, which is applied in the new field of preparation of 4-formylbenzofurazan, can solve the problems such as unsuitable for commercial synthesis and laborious

Inactive Publication Date: 2006-10-18
圣玛精细化工有限责任公司
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Problems solved by technology

[0006] The main disadvantage of this conventional method is that the step of oxidation of alcohols to aldehydes using magnesium dioxide is laborious and not suitable for commercial synthesis

Method used

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  • Method for preparing 4-formoxylbenzofuran
  • Method for preparing 4-formoxylbenzofuran
  • Method for preparing 4-formoxylbenzofuran

Examples

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Embodiment 1

[0027] Embodiment 1: Preparation of 4-dibromomethylbenzofura (II)

[0028] 4-Methylbenzofura (C 7 h 6 N 2 O) (100.0 g, 0.746 mol) was dissolved in 1.0 liter of chlorobenzene. N-Bromosuccinimide (398.5 g, 2.24 mol), AIBN (36.1 g, 0.149 mol) were added, and the reaction mixture was heated to 80-82 °C over 24 hours. After the reaction was completed, the reaction mixture was cooled to room temperature, filtered, and the filtered solution was washed with water twice. The resulting organic layer was dried over magnesium sulfate and vacuum distilled at 70-80°C. Diisopropyl ether (200 mL) was added to the residue product thus obtained, and stirred at 25°C for 30 minutes. The resulting product was filtered and dried under vacuum at 50-60°C. The resulting 4-(dibromomethyl)benzofura (II) was 160 grams, and by HPLC analysis, the purity varied between 97.0-99.0%, and the 4-(bromomethyl)benzofura(IV) ) content is less than 5%. 4-(Dibromomethyl)benzofura(II) was further characterized...

Embodiment 2

[0029] Embodiment 2: Preparation of 4-formylbenzofura (I)

[0030] 4-(Dibromomethyl)benzofura(II) (160.0 g, 0.342 mol) obtained in Example 1 was suspended in 800 ml of acetic acid and heated to 90°C. 2 L of HCl was slowly added to the above solution over a period of 8 hours while maintaining the temperature. This temperature was further maintained at 90°C. After the reaction was complete, the reaction mixture was cooled to room temperature. The reaction mixture was then cooled to 25°C and diluted with 1.6 liters of water. The product was extracted with 2 x 500 mL of dichloromethane. The organic layer was dried over sodium sulfate and vacuum distilled at 35-40°C to give 41 g of solid product. HPLC purity -99.0%. The product was further characterized using NMR and mass spectrometry techniques. NMR in CDCl 3 Inside, C-10: 1H (formyl) at δ 10.4, singlet; C-4: 1H δ 8.2 doublet; C-6: 1H δ 8.0 doublet; δC-5: 1H δ 7.6 triplet.

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Abstract

Improved, low-cost, scalable process for the preparation of 4-formylbenzofuran starting from 4-methylbenzofuran, wherein the novel 4-dibromobenzofuran is obtained as an intermediate . According to the method of the invention, 4-methylbenzofuran is brominated to obtain novel 4-dibromobenzofuran, which is then hydrolyzed to obtain 4-formylbenzofuran. 4-Formylbenzofura is a key intermediate in the production of isradipine for the treatment of hypertension and angina.

Description

technical field [0001] The present invention relates to an improved process for the preparation of 4-formylbenzofuran from 4-methylbenzofuran in which novel 4-(dibromomethyl)benzofuran compounds are intermediates. technical background [0002] 4-formylbenzofura shown in formula I: [0003] [0004] Is its chemical name 4-(4-benzofuryl)-1,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylic acid methyl 1-methyl ethyl ester Key intermediates of dipine, as described in German Patent no. DE 2949491; (1980), US Patent No. US 4466972 (1984). Isradi is usually used to treat hypertension and angina. [0005] 4-Formylpisperidone and its preparation are disclosed in European Journal of Medicinal Chemistry (1996), 31(1), 3-10, which is hereby incorporated by reference. The journal discloses a three-step method for preparing benzofura using various substituents of methyl benzofura. The above method involves the conversion of 4-methylbenzofura to 4-(bromomethyl)benzofura using N-bromo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D271/12
Inventor 拉哲拉姆·桑卡拉·萨布拉玛尼安瓦森特·乔希·海门特沙姆加那森·拉玛萨布拉玛尼安那塔拉金·萨赛安那雷阿南阿朱那恩·圣卡库玛·萨什贾亚玛尼·穆努萨米拉哲拉姆·巴派特·尤德萨拉瓦那·库玛·乔卡林阁姆
Owner 圣玛精细化工有限责任公司
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