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A kind of preparation method of pramoxine hydrochloride

A technology of pramoxine hydrochloride and potassium carbonate, which is applied in the field of pharmaceutical chemical synthesis, can solve problems such as dark color, achieve high reaction yield, less impurities, and avoid dyeing

Active Publication Date: 2019-02-19
SHANDONG CHENGCHUANG BLUE OCEAN PHARM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The above method synthesizes pramoxine hydrochloride, all with 4-n-butoxyphenol and N-(3-chloropropyl) morpholine as raw materials; and conventional commercially available 4-n-butoxyphenol, its preparation process is many It is prepared by reacting hydroquinone and brominated n-butane under alkaline conditions; because the phenolic hydroxyl group of hydroquinone directly interacts with the sp of the benzene ring 2 The hybridized carbon atoms are connected, and due to the conjugation of the unshared electron pair of the phenolic hydroxyl oxygen atom with the benzene ring, it is easily oxidized to form a quinone under aerobic conditions; the oxidation speed is faster under strong alkaline conditions, Therefore, 4-n-butoxyphenol often contains p-benzoquinone, an impurity oxidized by hydroquinone, which leads to the brown color of the prepared 4-n-butoxyphenol, so the commercially available 4-n-butoxyphenol has a darker color

Method used

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  • A kind of preparation method of pramoxine hydrochloride
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Examples

Experimental program
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Effect test

Embodiment 1

[0028] (1) Preparation of 4-n-butoxychlorobenzene

[0029] Add 771g of water, 84g of sodium hydroxide and 328.8g of n-bromobutane to the reaction flask, pass nitrogen protection, then add 257g of p-chlorophenol; the reaction temperature is slowly raised at 70-75°C for 15 hours. After the reaction was completed, the solution was cooled to 5-10°C and stirred for 1 hour, filtered, and the obtained off-white solid was beaten and washed with 650 g of water for half an hour, filtered again, and dried to obtain 317.6 g of white 4-n-butoxychlorobenzene; the molar yield was 86 %, the liquid phase purity is 99.52%.

[0030] (2) Preparation of N-(3-hydroxypropyl)morpholine

[0031] Add 609g of toluene, 174g of morpholine and 333.6g of 3-bromopropanol into the reaction flask, add 276g of potassium carbonate while stirring, and react at 55-60°C for 15 hours. After the reaction was completed, press filtration, and the filtrate was concentrated to remove toluene and unreacted raw materials...

Embodiment 2

[0035] (1) Preparation of 4-n-butoxychlorobenzene

[0036] Add 771g of water, 88g of sodium hydroxide and 356.2g of n-bromobutane to the reaction bottle, pass nitrogen protection, then add 257g of p-chlorophenol; the reaction temperature is slowly raised at 90-95°C for 10 hours. After the reaction, the solution was cooled to 5-10°C and stirred for 1 hour, filtered, and the obtained off-white solid was beaten and washed with 650 g of water for half an hour, filtered again, and dried to obtain 319.5 g of white 4-n-butoxychlorobenzene; the molar yield was 86.5 %, the liquid phase purity is 99.51%.

[0037] (2) Preparation of N-(3-hydroxypropyl)morpholine

[0038] Add 913.5 g of toluene, 174 g of morpholine and 556 g of 3-bromopropanol into the reaction flask, add 331.2 g of potassium carbonate while stirring, and react at 75-80° C. for 8 hours. After the reaction was completed, press-filtered, and the filtrate was concentrated to remove toluene and unreacted raw materials to ob...

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Abstract

The invention belongs to the field of medical chemical synthesis, and particularly relates to a preparation method of pramoxine hydrochloride. The method comprises the following steps: (1) carrying out reaction on parachlorophenol and brominated n-butane under alkaline conditions to obtain an intermediate 4-n-butoxychlorobenzene; (2) carrying out reaction on morpholine and 3-bromopropanol under alkaline conditions to obtain an intermediate N-(3-hydroxypropyl)morpholine; and (3) carrying out reaction on the 4-n-butoxychlorobenzene and N-(3-hydroxypropyl)morpholine under alkaline conditions, and carrying out extraction, washing, drying and salification to obtain the pramoxine hydrochloride. The preparation method has the advantages of simple technique, high production safety and reliability and high reaction yield. The prepared pramoxine hydrochloride has the advantages of high purity and fewer impurities, and is very suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of pharmaceutical chemical synthesis, and in particular relates to a preparation method of pramoxine hydrochloride. Background technique [0002] Pramocaine hydrochloride is a non-benzoate topical anesthetic; it produces satisfactory topical anesthesia and is fairly well tolerated by the skin and non-delicate mucous membranes. For patients who are allergic to other local anesthetics, the risk of cross-allergic reactions is minimized due to its special chemical structure. Pramocaine hydrochloride can also relieve the itching and pain of skin and rectal diseases, and can also be added to pet toiletries to relieve itching and pain. [0003] In the prior art, the traditional synthetic method of pramoxine hydrochloride uses 4-n-butoxyphenol and N-(3-chloropropyl)morpholine as raw materials to carry out nucleophilic substitution reaction, and its reaction equation is as follows: [0004] [0005] For example, patent CN...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D295/088
CPCC07D295/088
Inventor 李跃东王庭见杨彦军王素兰张伟
Owner SHANDONG CHENGCHUANG BLUE OCEAN PHARM TECH CO LTD
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