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Synthesis of 5-bromo phthalide

A technology of bromophthalide and synthesis method, which is applied in the field of synthesis of 5-bromophthalide, and can solve the problems of "three wastes", long synthesis route, and high cost

Inactive Publication Date: 2005-07-06
ZHEJIANG XIANFENG TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] 5-Bromophthalide is an important intermediate in the synthesis of the antidepressant drug citalopram, but there are few reports on the synthesis of 5-bromophthalide as the target product at home and abroad
The synthesis route of this method is long, and the reduction reaction adopts metal reduction, the cost is high, and the "three wastes" are large.

Method used

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  • Synthesis of 5-bromo phthalide
  • Synthesis of 5-bromo phthalide
  • Synthesis of 5-bromo phthalide

Examples

Experimental program
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Effect test

example 1

[0024] Add 260ml 98% concentrated sulfuric acid and 100g (0.68mol) phthalimide into a 500ml four-necked flask, stir the solution, add 59g (85%, 0.80mol) nitric acid (dissolved in 54ml 98 % concentrated sulfuric acid), the dropwise reaction was continued for 6 hours at 20-25°C. Pour the reaction mixture into 1000ml of crushed ice, filter at room temperature, wash with water until neutral, and dry to obtain 92.7g of white solid, yield 71.0%, mp: 198-200°C.

example 2

[0026] Add 22.4g (0.40mol) of iron powder, 1g (0.019mol) of ammonium chloride, 2ml of 36% (0.065mol) concentrated hydrochloric acid, 2ml (0.035mol) of glacial acetic acid, 100ml of water into a 500ml four-necked flask, and heat to 40-50 ℃, add 19.2g (0.1mol) 4-nitrophthalimide in batches, under vigorous stirring, raise the temperature to 60-70 ℃, keep the temperature for 5 hours, add a small amount of saturated sodium carbonate solution dropwise to make the system The PH value is neutral, cool and filter to obtain a solid, dry, dissolve the material with 100-120ml of DMF, heat to about 70°C, stir for 15 minutes, heat filter, evaporate the filtrate to dryness, filter, wash the filter cake with ethanol to obtain a light yellow The solid is 12.8g, the yield is 79.0%, mp.293~295℃.

example 3

[0028] Add 400ml of DMF to a 1000ml autoclave, self-made skeleton nickel, 19.2g (0.1mol) 4-nitrophthalimide, replace with hydrogen three times, fill with hydrogen to 0.6Mpa, stir and heat up to about 55°C for reaction 4 hours. Stop the reaction, open the lid of the kettle, draw out the feed liquid, evaporate to dryness, filter, wash the filter cake with a small amount of ethanol to obtain 15.4 g of light yellow solid, yield 95.0%, m.p.293-295°C.

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Abstract

The invention relates to a process for synthesizing intermediate 5-bromo-phthalide of Citalopram for treating depression, characterized in that the product is prepared by nitrification, nitro reduction, carbonyl reduction, and diazotization-bromination, etc. with phthalic imidine as raw materials in yield above 48%.

Description

technical field [0001] The invention belongs to the field of pharmaceutical intermediates and relates to a synthesis method of 5-bromophthalide. Background technique [0002] 5-Bromophthalide is an important intermediate in the synthesis of antidepressant citalopram, but there are few reports on the synthesis of 5-bromophthalide as the target product at home and abroad. Master's degree thesis of Zhejiang University of Technology (2002) - the application of organic chemical reactions promoted by samarium diiodide and metal ytterbium in organic synthesis and the synthesis of 5-bromophthalide reported: using phthalic anhydride and ammonium bicarbonate as raw materials, through Acylation reaction, fuming nitric acid and fuming sulfuric acid mixed acid nitration reaction, and reduction by reducing agent R1, R2, and diazotization and Sandmeyer reaction to prepare 5-bromophthalide. The synthesis route of this method is long, and the reduction reaction adopts metal reduction, so th...

Claims

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Application Information

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IPC IPC(8): C07D307/88
Inventor 王文标
Owner ZHEJIANG XIANFENG TECH
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