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Preparation method for (6-Chloro-pyridazino-3-yl) formic acid

A technology of chloropyridazine and formic acid, which is applied in organic chemistry and other fields, can solve problems such as low chlorination efficiency, strong corrosion, and high toxicity, and achieve the effect of increasing yield

Active Publication Date: 2014-05-28
SINO HIGH CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the conventional chlorination reagents used in chlorination reactions have the characteristics of high toxicity, strong corrosion and low chlorination efficiency.
Most of the oxidants used in the oxidation process are heavy metal salts, which cause serious pollution and are not conducive to industrial production

Method used

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  • Preparation method for (6-Chloro-pyridazino-3-yl) formic acid
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  • Preparation method for (6-Chloro-pyridazino-3-yl) formic acid

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Experimental program
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Effect test

Embodiment 1

[0037] Embodiment 1: the preparation of 6-methyl-3 (2H)-pyridazinone

[0038] Put ethyl levulinate (43.3g, 0.3mol), 80wt% hydrazine hydrate (35g, 0.55mol), 10mL ethanol and 20g sodium hydroxide into the reaction flask in sequence, stir and heat to 85-90°C, and keep for 5 hours; Cool to room temperature, adjust the pH to weak alkaline with dilute hydrochloric acid, then add 300mL of toluene, stir for 30 minutes and let it stand; separate the toluene phase and dry it with anhydrous sodium sulfate, remove the desiccant, slowly add 20mL of liquid bromine, and then heat To 95 ~ 100 ℃, keep for 3 hours; add 100mL of glacial acetic acid, stir well, stand still, separate layers; separate the acetic acid layer, add 40g of sodium acetate, boil and keep for 1 hour; remove the solvent under reduced pressure, and cool the residue After that, colorless crystals were precipitated, and 33.2 g of 6-methyl-3(2H)-pyridazinone was obtained by suction filtration, m.p.: 130.2-130.8°C, and the yield...

Embodiment 2

[0042] Embodiment 2: Preparation of 3-chloro-6-methylpyridazine

[0043] Add 6-methyl-3(2H)-pyridazinone (55g, 0.5mol), tetramethylammonium chloride (49.5g, 0.45mol), and triphosgene (237.4g, 0.8mol) into the reaction flask in sequence; stir , heated to 145°C and kept for 5 hours; after the reaction solution was cooled to room temperature, it was slowly poured into about 1.5Kg of ice and stirred for 2 hours; phase, the aqueous phase was extracted twice with ethyl acetate, the organic phases were combined, and dried with anhydrous sodium sulfate; the ethyl acetate was removed under reduced pressure to obtain 57.1 g of 3-chloro-6-methylpyridazine as a light yellow solid, m.p.: 48.6-50.0°C, yield 89%.

[0044] The Spectral Data of 3-Chloro-6-methylpyridazine

[0045] 1 HNMR (CDCl 3 ,ppm):δ7.664(d,1H);7.633(d,1H);2.281(s,3H).

Embodiment 3

[0046] Embodiment 3: Preparation of 6-chloropyridazine-3-carboxylic acid

[0047] Put 3-chloro-6-methylpyridazine (64.3g, 0.5mol) and 650mL cyclohexane into the reaction flask, stir and cool with ice water; %H 2 o 2 (79.4g, 0.7mol) solution was added within 40 minutes; the temperature was raised to 55°C and reacted for 2 hours; cooled to room temperature, the organic phase was separated and dried with anhydrous sodium sulfate; cyclohexane was removed under reduced pressure to obtain 56g6- Chlorpyridazine-3-carboxylic acid is a white solid, m.p.: 139.2-141.1°C, the yield is 71%.

[0048] Spectral data of 6-chloropyridazine-3-carboxylic acid: 1 HNMR (CDCl 3 ,ppm): δ8.424(d,1H);7.937(d,1H).

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Abstract

The invention discloses a preparation method for (6-Chloro-pyridazino-3-yl) formic acid. The preparation method comprises the following steps: carrying out a cyclization and dehydrogenation reaction on ethyl levulinate firstly to obtain 6-methyl-3(2H)-pyridazinone; then, carrying out a chlorination to obtain 3-chloro-6-methyl pyridazine; finally, carrying out an oxidation reaction to obtain 6-chloropyridazine-3-carboxylicacid methyl acid. The method has the advantages of simple process, simplicity and convenience in operation, security and practicality.

Description

technical field [0001] The invention belongs to the field of fine chemical industry, and in particular relates to a preparation method of pyridazine derivatives, in particular to a method for chlorination of pyridazine ring and side chain oxidation thereof. Background technique [0002] Pyridazine compounds are a class of heterocyclic compounds with good biological activity. Different groups introduced into the pyridazine structure can produce a series of derivatives with antibacterial activity, making them play an important role in pesticides and medicines. In 1949, Schoene et al. reported for the first time that 4-hydroxypyridazinone had the property of strongly inhibiting plant cell division, and was used as a plant growth regulator in agricultural production. Since then, it has created a field of new pesticides based on the pyridazine ring (Li Hun Sen. Organic Chemistry, 2005, 25:204~207.). The herbicide Maleic hydrazide (MH), as the earliest commercialized pyridazine c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D237/24
CPCC07D237/24
Inventor 严留新汤浩张海娟王大胜陈年海
Owner SINO HIGH CHINA
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