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Process for preparing 6-chlorine-1,3-dimethyl uracil

A technology of dimethyluracil and hydroxyl, which is applied in the field of preparation of 6-chloro-1,3-dimethyluracil I, can solve the problems of low product quality, high production cost, difficult operation, etc., and achieve the product The effect of high yield, low cost and simple method

Active Publication Date: 2012-08-01
江西吉翔医药化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The chlorination step of the existing process has disadvantages such as low yield and difficult operation, resulting in high production cost and low product quality

Method used

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  • Process for preparing 6-chlorine-1,3-dimethyl uracil
  • Process for preparing 6-chlorine-1,3-dimethyl uracil
  • Process for preparing 6-chlorine-1,3-dimethyl uracil

Examples

Experimental program
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Effect test

Embodiment 1

[0019] Example 1 Add 150 kg of 6-amino-1,3-dimethyluracil, 600 kg of water, and 50 kg of concentrated sulfuric acid (98%) into a 1000 L reactor, gradually heat up to reflux, keep for 5 hours, and cool Crystallized, centrifuged, and dried to obtain 140.5 kg of milky white crystals of 6-hydroxy-1,3-dimethyluracil, with a melting point of 121°C-124°C and a yield of 93.0%. Into a 500 L dry reaction kettle, pump 450 kg of phosphorus oxychloride and 150 kg of phosphorus trichloride respectively, lower the temperature to below 20°C, slowly add 14 kg of water dropwise, and add a total of 50 kg of the above-prepared 6 -Hydroxy-1,3-dimethyluracil, after adding, gradually raise the temperature to reflux, stop heating after 3 hours of heat preservation, slowly inject vacuum, start decompression recovery of phosphorus oxychloride, until about 90℃, the material in the kettle becomes Stop the distillation when it is cloudy, transfer the material to a kettle with 500kg of ice water in advance...

Embodiment 2

[0020] Example 2 Add 150 kg of 6-amino-1,3-dimethyluracil, 400 kg of water, and 150 kg of concentrated hydrochloric acid (36%) into a 1000 L reactor, gradually heat up to reflux, keep for 4 hours, and cool Crystallize below 30°C, centrifuge, freeze the mother liquor below 10°C, precipitate solids, centrifuge, and dry to obtain 139 kg of off-white crystalline product 6-hydroxy-1,3-dimethyluracil, melting point 121°C-124°C, yield The rate is 92.0%. Into a 500 L dry reaction kettle, pump 600 kg of phosphorus oxychloride, lower the temperature to below 20°C, slowly add 20 kg of methanol dropwise, and add a total of 50 kg of 6-hydroxyl-1,3- After the addition of dimethyl uracil, the temperature is gradually raised to reflux. After 5 hours of heat preservation, the heating is stopped, and the vacuum is slowly injected, and the phosphorus oxychloride is recovered under reduced pressure. When the material in the kettle becomes cloudy at about 90°C, the distillation is stopped. Transf...

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Abstract

The invention provides a process for preparing 6-chlorine-1,3-dimethyl uracil, which comprises the steps of using 6-amino-1,3-dimethyl uracil as raw materials; subjecting to acidic hydrolysis and chlorinating agent chlorination; and synthesizing the 6-chlorine-1,3-dimethyl uracil. Compared with conventional additives, additives including alcohol, water and the like, which are easy to react with phosphorus oxychloride, are added during chlorination, so that the yield of chlorination is obviously increased to 80%. Compared with the existing preparing processes, the process has the advantages that raw materials are cheap and easy to obtain, the reaction conditions are mild, the yield is high, and the cost is low. The process is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis chemistry, and in particular relates to a new method for preparing 6-chloro-1,3-dimethyluracil I. [0002] Background technique [0003] 6-Chloro-1,3-dimethyluracil I is an important intermediate in the synthesis of antihypertensive drug urapidil and antiarrhythmic drug nifekalant. [0004] Urapidil is an antihypertensive drug first developed and marketed by Byk Gulden in 1981. It has been approved for marketing in more than 30 countries including Britain and France. It is clinically used for the treatment of primary renal hypertension, pheochromocytoma and cardiac exhaustion etc. The drug is the first marketed antihypertensive drug with peripheral and central activity, and it can affect the α on the postsynaptic membrane of peripheral vascular smooth muscle and sympathetic nerve terminal 1 -Receptors have a blocking effect and directly excite brainstem 5-HT 1A Receptor, produces c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/553
Inventor 郑土才聂孝文况庆雷郑建霖魏源陈锋王吉
Owner 江西吉翔医药化工有限公司
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