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Synthesis process of 6-methoxy pyridazine-3- carboxylic acid

A technology of methoxypyridazine and synthesis process, applied in the direction of organic chemistry, etc., can solve the problems of complex preparation, limited sources, and limitations of 6-hydroxypyridazine-3-carboxylic acid, and shorten the synthesis steps and reduce the operation process. , suitable for the effect of industrial production

Inactive Publication Date: 2010-12-29
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] This process route, the preparation of the starting material 6-hydroxypyridazine-3-carboxylic acid is relatively complicated, the source is limited, and there is no industrial synthesis process for it in China at present
Therefore, the preparation of the target compound 6-methoxypyridazine-3-carboxylic acid is limited

Method used

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  • Synthesis process of 6-methoxy pyridazine-3- carboxylic acid
  • Synthesis process of 6-methoxy pyridazine-3- carboxylic acid
  • Synthesis process of 6-methoxy pyridazine-3- carboxylic acid

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Embodiment 1

[0019] Using 3-chloro-6-methylpyridazine as the starting material, the methyl group was oxidized to carboxylic acid to obtain 6-chloropyridazine-3-carboxylic acid, which was methoxylated with chlorine to obtain the target compound with a total yield of 37.7%.

[0020]

[0021] Preparation of 6-chloropyridazine-3-carboxylic acid In ice-cooling, 8 g (0.06 mol) of 3-chloro-6-methylpyridazine was added to 60 ml of concentrated sulfuric acid. Under stirring, 35 g (0.12 mol) of potassium dichromate was added in portions. After reacting at 50° C. for 2 h, add 200 ml of ice water to dilute after cooling, and extract with ethyl acetate 200 ml×5. The extracts were combined, dried over anhydrous sodium sulfate, and reduced to dryness under reduced pressure. The residue was recrystallized from methanol to obtain 6.2 g of white crystalline powder with a yield of 65%.

[0022] Preparation of 6-methoxypyridazine-3-carboxylic acid In 50 ml of anhydrous methanol, 2.2 g (0.04 mol) of sodi...

Embodiment 2

[0025] Using 3-chloro-6-methylpyridazine as the starting material, the methyl group was oxidized to carboxylic acid to obtain 6-chloropyridazine-3-carboxylic acid, which was methoxylated with chlorine to obtain the target compound with a total yield of 30.2%.

[0026]

[0027] Preparation of 6-chloropyridazine-3-carboxylic acid Under ice cooling, 8 g (0.06 mol) of 3-chloro-6-methylpyridazine was added to 60 ml of 50% sulfuric acid. Under stirring, 38 g (0.24 mol) of potassium permanganate was added in portions. After reacting at 80° C. for 2 h, add 200 ml of ice water to dilute after cooling, filter, and extract the filtrate with ethyl acetate 100 ml×4. The extracts were combined, dried over anhydrous sodium sulfate, and reduced to dryness under reduced pressure. The residue was recrystallized from methanol to obtain 5.0 g of white crystalline powder with a yield of 52% and a melting point of 148-151°C.

[0028] Preparation of 6-methoxypyridazine-3-carboxylic acid In 50 ...

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Abstract

The invention relates to a synthetic process of an intermediate 6-methoxypyridazine-3-carboxylic acid. The synthetic process comprises the following steps: (1) adding 3-chloro-6-methylpyridazine to sulfuric acid in ice bath, adding an oxidant while stirring, allowing react at 20-80 DEG C, cooling, adding ice water for dilution, extracting, merging extracts, drying, depressurizing to dryness, and recrystallizing a residue to obtain 6-chloropyridazine-3-carboxylic acid; and (2) adding sodium methoxide and the 6-chloropyridazine-3-carboxylic acid to a solvent while stirring, performing reflux reaction on a system, depressurizing reaction liquid to remove excessive solvent, adding the ice water, adjusting pH value with concentrated hydrochloric acid, keeping standing overnight, filtering, andrecrystallizing a filter cake with water to obtain the 6-methoxypyridazine-3-carboxylic acid. The synthetic process has the beneficial effects of changing a starting material which is under industrial production in China and is available, shortening synthetic steps, reducing operating procedure and causing the 6-methoxypyridazine-3-carboxylic acid to be more applicable to industrial production.

Description

technical field [0001] The invention relates to a synthesis process of an intermediate 6-methoxypyridazine-3-carboxylic acid. Background technique [0002] Pyridazine compounds have good biological activity, and have various pharmacological activities in antiprotozoal, antiflagellate and amoeba. For example, imidazole or benzimidazole compounds have low biological activity and low oral bioavailability for Onchocerca volvulus, Wucherera bancrofti, Brugia malayi and Brugia timori four parasites, thus limiting the development of imidazole compounds as drugs, in order to overcome the defects, Combining the relationship between structure and activity, people introduced the structure of pyridazine ring into the molecular structure, and obtained a series of imidazol[1,2-b]pyridazine carboxylate compounds, which have inhibitory effect on the central nervous system of parasites. active and can be used in anthelmintic drugs. In addition, it also has antihypertensive, anticancer, diu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D237/24
Inventor 王凯陈达
Owner WUHAN INSTITUTE OF TECHNOLOGY
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