Synthesis method of 3,4-dimethoxy-6-nitrobenzoic acid

A technology of nitrobenzoic acid and dimethoxy, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of difficult control of reaction process, difficult industrialization, environmental pollution, etc. Inexpensive, simple preparation method and easy-to-obtain raw materials

Inactive Publication Date: 2017-06-16
CHONGQING MEDICAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
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Problems solved by technology

In fact, preparation by oxidation of potassium permanganate (J. Sedelmeier, S.V.Ley, I.R. Baxendale, M. Baumann, Org. Lett., 2010, 12, 3618-3621.) will produce a large amount of manganese slag, which not only wastes resources, but also Can cause serious environmental pollution, industrialization difficulty is big; And prepare through hydrogen peroxide oxidation (CN101353328A), react violently, reaction process is difficult to control, cause safety accident easily, industrialization difficulty is big

Method used

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  • Synthesis method of 3,4-dimethoxy-6-nitrobenzoic acid
  • Synthesis method of 3,4-dimethoxy-6-nitrobenzoic acid
  • Synthesis method of 3,4-dimethoxy-6-nitrobenzoic acid

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Embodiment 1

[0025] In 3,4-dimethoxy-6-nitrobenzaldehyde (10g), add reaction medium (water 20mL, methanol 30mL), add acetic acid (3.5mL), 30% hydrogen peroxide (9mL), stir well Add sodium chlorite (content 80%, 9g) and dissolve in water (5mL); stir and heat up to about 50°C, monitor the reaction, add sodium bisulfite (10.5g) to quench the reaction after the reaction is completed, and evaporate the solvent to dryness. The product was dissolved in sodium hydroxide (6g×10mL) solution, filtered to remove impurities, and the filtrate was added with sulfuric acid until the pH was 1 to precipitate the product, filtered, and dried. 10 g of the product was obtained (93% yield, 99.5% purity by HPLC). NMR 1 H NMR (600MHz, CDCl 3 )δ7.41(s,0H),7.28(s,0H),4.01(d,J=8.0Hz,6H). 13 C NMR (101MHz, CDCl3) δ171.40, 153.75, 148.71, 124.60, 121.63, 112.33, 110.34, 56.09, 56.03.

Embodiment 2

[0027] Water (20 mL) and methanol (20 mL) were added to 3,4-dimethoxy-6-nitrobenzaldehyde (10 g), followed by stirring. Then add sodium dihydrogen phosphate (7.5g), 50% hydrogen peroxide (9mL), then add sodium chlorite (content 80%, 9g) dissolved in water (5mL), stir and heat up to about 40°C for reaction, monitor Reaction, after the reaction is over, add sodium bisulfite (16g) to quench the reaction, evaporate the solvent to dryness, dissolve the product in potassium hydroxide (6g×10mL) solution, filter to remove impurities, add hydrochloric acid to the filtrate until the pH is 1 to precipitate the product, filter ,drying. 9.7 g of the product was obtained (90% yield, 99.3% HPLC purity). NMR 1 H NMR (600MHz, CDCl 3 )δ7.41(s,0H),7.28(s,0H),4.01(d,J=8.0Hz,6H). 13 C NMR (101MHz, CDCl3) δ171.40, 153.75, 148.71, 124.60, 121.63, 112.33, 110.34, 56.09, 56.03.

[0028] The inventors of the present invention found in the process of preparing 3,4-dimethoxy-6-nitrobenzoic acid from...

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Abstract

The invention provides a synthesis method of 3,4-dimethoxy-6-nitrobenzoic acid. The 3,4-dimethoxy-6-nitrobenzoic acid is successfully prepared from 3,4-dimethoxy-6-nitrobenzaldehyde by carefully selecting a composite oxidant formed through combining sodium chlorite and hydrogen peroxide according to a specific ratio, and adopting a specific solvent and a specific reaction temperature. Use of a high-polluting substance potassium permanganate is avoided in the reaction process, so the problem of serious pollution is solved; and the method also has the advantages of mild reaction process (not more than 60 DEG C), high safety, no use of specific devices, and suitableness for industrial production.

Description

technical field [0001] The invention relates to a synthesis method of 3,4-dimethoxy-6-nitrobenzoic acid, belonging to the technical field of medicinal chemistry. Background technique [0002] 2-Chloro-4-amino-6,7-dimethoxyquinazoline (CAS No. 23680-84-4), is dorazosin mesylate (prostatic hyperplasia drug), prazosin hydrochloride (treatment of high Blood pressure), terazosin hydrochloride (treatment of high blood pressure), terazosin hydrochloride (treatment of mild to moderate essential hypertension), alfuzosin (treatment of benign prostatic hyperplasia) and other important intermediates of oxazosin drugs . [0003] [0004] In industry, 2-chloro-4-amino-6,7-dimethoxyquinazoline is mainly synthesized from 3,4-dimethoxy-6-nitrobenzoic acid, 3,4-dimethoxy The structure of base-6-nitrobenzoic acid is as follows: [0005] [0006] At present, 3,4-dimethoxy-6-nitrobenzoic acid is mainly prepared from 3,4-dimethoxy-6-nitrobenzaldehyde through the oxidation of potassium pe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/59
CPCC07C201/12C07C205/59
Inventor 袁建勇王华均田青强
Owner CHONGQING MEDICAL UNIVERSITY
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