Method for preparing lidocaine hydrochloride

A technology of lidocaine hydrochloride and hydrochloric acid, which is applied to the preparation of carboxylic acid amides, organic compounds, amino compounds, etc., to achieve the effects of simple synthesis process, high economy and environmental protection

Active Publication Date: 2016-02-03
ZHEJIANG ESIGMA BIOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems existing in the existing technology for producing lidocaine hydrochloride, the inve

Method used

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  • Method for preparing lidocaine hydrochloride
  • Method for preparing lidocaine hydrochloride
  • Method for preparing lidocaine hydrochloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Preparation of intermediate 2,6-dimethylaniline

[0027] Add 24.43g (0.2mol) of 2,6-xylenol, 63.1g (0.6mol) of ammonia water, 1.06g of 5% Pd / C, 2.52g (0.02 mol), react at 185°C for 6h, cool down to room temperature, filter, recover Pd / C and use it mechanically; distill the filtrate under reduced pressure, recover 2,6-dimethylcyclohexanone and use it mechanically next time, add water to wash the residue once, let stand and separate , the oil layer is 23.35 g of the intermediate 2,6-dimethylaniline, the HPLC purity is 98.32%, and the yield is 94.73%.

[0028] (2) preparation of lidocaine hydrochloride

[0029] Add 15.12 g (0.28 mol) of sodium methoxide, 24.24 g (0.2 mol) of intermediate 2,6-dimethylaniline and 31.9 g (0.22 mol), heated to 95°C, and distilled off the methanol generated during the reaction until no methanol was distilled out, then continued the reaction for 30 minutes, cooled to room temperature, added dichloroethane to dissolve, washed twice with wat...

Embodiment 2-3

[0031] The preparation of embodiment 2-3 intermediate 2,6-dimethylaniline

[0032] Using the same operating method as in Example 1 (1), the same amount of 2,6-xylenol, the difference is the amount of ammonia, Pd / C and 2,6-dimethylcyclohexanone, the experimental results obtained are shown in the table 1 shows:

[0033] Table 1:

[0034]

Embodiment 4

[0035] The preparation of embodiment 4 lidocaine hydrochloride

[0036] Add 12.96 g (0.24 mol) of sodium methoxide, 24.24 g (0.2 mol) of intermediate 2,6-dimethylaniline and 34.8 g (0.24 mol), heated to 90°C, and distilled off the methanol generated during the reaction until no methanol was distilled out, then continued the reaction for 30 minutes, cooled to room temperature, added dichloroethane to dissolve, washed twice with water, and stood to separate layers. The organic layer is the dichloroethane solution of lidocaine base.

[0037] In the ethylene dichloride solution of above-mentioned lidocaine base, add hydrochloric acid 2.42g, regulate PH with hydrogen chloride then to be 4, add gac and reflux 30min, filter, filtrate is concentrated, crystallization by cooling, dry to obtain lidocaine hydrochloride 48g, HPLC purity is 99.32%, the yield is 87.96%.

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Abstract

The invention provides a method for preparing lidocaine hydrochloride, and belongs to the technical field of anesthetic synthesis. The method comprises the following steps: by taking 2,6-xylenol as a raw material, Pd/C as a main catalyst and 2,6-dimethylcyclohexanone as a promoter, performing liquid phase amination with ammonia water at high temperature, thereby obtaining a midbody 2,6-dimethylaniline; enabling sodium methylate, 2,6-dimethylaniline and N,N-lignocaine methyl acetate as raw materials to react at 90-95 DEGC, distilling while reaction is performed to remove methanol till no methanol can be evaporated out, continuously reacting for 30 minutes, cooling to the room temperature, adding dichloroethane, washing with water, and leaving to stand to layer, thereby obtaining an organic layer, namely, a lidocaine based dichloroethane solution; further adding hydrochloric acid into the lidocaine based dichloroethane solution, adjusting the pH value to be 3.5-4 by using hydrogen chloride, adding activated carbon to reflux for 20-40 minutes, filtering, concentrating the filtrate, cooling, crystallizing, and dying, thereby obtaining lidocaine hydrochloride. The lidocaine hydrochloride prepared by using the method is simple in synthesis process and high in product purity, that is, the purity can be greater than 99%, and the total yield is greater than 84%.

Description

technical field [0001] The invention belongs to the technical field of anesthetic synthesis, in particular to a preparation method of lidocaine hydrochloride. Background technique [0002] The chemical name of lidocaine hydrochloride is N-(2,6-xylyl)-2-(diethylamino)acetamide hydrochloride-hydrate, which is a common amide local anesthetic. The patch can be used as a topical anesthetic, has analgesic effect, can be absorbed through the skin or mucous membrane, and is clinically used for local infiltration anesthesia before superficial surgery on the skin or mucous membrane; it can also relieve postherpetic neuralgia, just like other local anesthetics , topical application has a certain antipruritic effect, and also has antiarrhythmic effect. [0003] At present, the research on lidocaine at home and abroad mainly focuses on preparations, such as lidocaine hydrochloride injection, compound lidocaine cream, lidocaine gel and so on. However, the synthetic method of lidocaine h...

Claims

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Application Information

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IPC IPC(8): C07C237/04C07C231/02C07C209/18C07C211/45
Inventor 吴中华张小朋陈贵才徐天华何奇雷闻鸣
Owner ZHEJIANG ESIGMA BIOTECH CO LTD
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