Novel synthetic method of o-ethoxyl benzamidine hydrochloride

A technology of o-ethoxybenzamidine hydrochloride and ethoxybenzamidine hydrochloride, applied in the field of synthesis of o-ethoxybenzamidine hydrochloride, can solve the problem of unfavorable small-scale enterprises to implement and implement Problems such as high difficulty and large equipment investment have achieved the effect of low requirements for production equipment and environmental conditions, simple process and high output

Inactive Publication Date: 2013-05-08
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method has the advantages of rapid response, less environmental pollution and easy separation, it is dangerous to use flammable hydrogen for large-scale production, and for small and medium-scale production, the equipment investment is large and the implementation is difficult. Facilitate the implementation of small-scale enterprises

Method used

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  • Novel synthetic method of o-ethoxyl benzamidine hydrochloride

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Step A: Add o-hydroxybenzonitrile (25g, 210mmol), potassium carbonate (87g, 630mmol) and ethyl bromide (34.3g, 314.8mmol) into acetone (300mL), stir, and reflux for 4 hours. After cooling and filtering, the filtrate was distilled under reduced pressure to obtain o-ethoxybenzonitrile as a colorless transparent liquid with a yield of 94%.

[0017] Step B: Add o-ethoxybenzonitrile (30g, 200mmol), hydroxylamine hydrochloride (21g, 300mmol), and potassium carbonate (41g, 300mmol) into ethanol (60mL), heat to reflux for 1.5 hours, and distill off the solvent under reduced pressure , add concentrated hydrochloric acid (30%, 200mL), slowly add zinc powder (20g) in batches under stirring, stir at room temperature for 1 hour, filter to remove unreacted zinc powder, and distill off the solvent under reduced pressure to obtain a sticky gel. Add diethyl ether (20 mL) to the liquid, filter, and collect white crystals that are o-ethoxybenzamidine hydrochloride, with a yield of 86%.

Embodiment 2

[0019] Step A: Add o-hydroxybenzonitrile (25g, 210mmol), sodium carbonate (67g, 630mmol) and ethyl bromide (34.3g, 314.8mmol) into acetone (300mL), stir and reflux for 3 hours. After cooling and filtering, the filtrate was distilled under reduced pressure to obtain o-ethoxybenzonitrile as a colorless transparent liquid with a yield of 90%.

[0020] Step B: Add o-ethoxybenzonitrile (15g, 100mmol), hydroxylamine hydrochloride (11g, 150mmol), and potassium carbonate (21g, 150mmol) into ethanol (40mL), heat to reflux for 0.5 hours, and distill off the solvent under reduced pressure , the residue was dissolved in concentrated hydrochloric acid (30%, 100mL), slowly added iron powder (10g) in batches under stirring, stirred at room temperature for 3 hours, filtered to remove the solid, distilled off most of the solvent under reduced pressure and added diethyl ether (10mL ), filtered, and the white crystals collected were o-ethoxybenzamidine hydrochloride, with a yield of 93%.

Embodiment 3

[0022] Step A: Add o-hydroxybenzonitrile (25g, 210mmol), sodium carbonate (67g, 630mmol) and diethyl sulfate (38.5g, 250mmol) into tetrahydrofuran (200mL), stir and reflux for 5 hours. After cooling and filtering, the filtrate was distilled under reduced pressure to obtain o-ethoxybenzonitrile as a colorless transparent liquid with a yield of 95%.

[0023] Step B: Add o-ethoxybenzonitrile (30g, 200mmol), hydroxylamine hydrochloride (21g, 300mmol), and potassium carbonate (41g, 300mmol) into tetrahydrofuran (60mL), heat to reflux for 1 hour, and distill off the solvent under reduced pressure , add dilute hydrochloric acid (10%, 400mL), slowly add iron powder (15g) in batches under stirring, stir at room temperature for 3 hours, filter, distill off the solvent under reduced pressure to obtain a colloidal viscous liquid, add diethyl ether (20mL ) washing, filtering, and collecting white crystals which are o-ethoxybenzamidine hydrochloride with a yield of 90%.

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Abstract

The invention provides a novel synthetic method of o-ethoxyl benzamidine hydrochloride, and belongs to the field of medical intermediate synthesis. The method comprises the following steps of: A, based on o-hydroxyl benzonitrile as a raw material, performing a reflux reaction on the o-hydroxyl benzonitrile and an ethylating reagent in acetone containing an acid-binding agent to obtain o-ethoxyl benzonitrile, wherein the yield is 92-97%; and B, performing a reflux reaction on o-ethoxyl benzonitrile and hydroxylamine hydrochloride in ethanol to obtain o-ethoxyl benzamidoxime, removing ethanol and adding hydrochloric acid, and performing hydrogenation reaction by stirring iron powder or zinc power at constant temperature to prepare o-ethoxyl benzamidine, wherein the yield is 85-90%. Compared with synthetic methods in the prior art, the method provided by the invention is simple and convenient in step, low in cost and available in raw materials, low requirements in production equipment and environmental condition and high in yield, and is very suitable for industrial production.

Description

Technical field: [0001] The invention belongs to the field of pharmaceutical intermediates and relates to a synthesis method of o-ethoxybenzamidine hydrochloride. Background technique: [0002] Amidine compounds are important pharmaceutical intermediates and are widely used in drugs such as antibiotics, anti-inflammatory drugs and anthelmintics. At the same time, nitrogen heterocyclic compounds can be synthesized from amidine compounds, which has important synthetic value. As the application prospects of amidines are constantly expanding, some new synthetic methods are constantly appearing. Some of the more important methods are the improved Pinner method, amide acetal method, ketoxime method and carboxylic acid method, Sm / trimethylchlorosilane / H2O (trace) system method. Among the amidine compounds, o-ethoxybenzamidine is a new pharmaceutical intermediate, and the above methods are not suitable for its industrial production due to technical or cost limitations. Patent CN1...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C257/18
Inventor 王鹏钟旭世许齐勇文盼
Owner SHANDONG UNIV OF SCI & TECH
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