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Preparation of 6-(3,4-diamino phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-ketone key intermediate of 2-(4-methoxyphenyl)-5(6)-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl)benzimidazole

A technology of diaminophenyl and dihydropyridazine, applied in the field of key intermediates of pimobendan, can solve problems such as being unsuitable for industrial scale-up production, and achieve the effects of short process route and mild reaction process

Active Publication Date: 2017-02-22
SOUTHEAST UNIV +1
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Problems solved by technology

[0012] Based on the above-mentioned methods of synthesizing pimobendan that have been publicly reported, the US4361563 patent, the synthetic route reported by Pu Riyang, the synthetic route reported by Wang Sisi and the synthetic route reported by Xu Youjun respectively use Br, which is limited in industrial use in large quantities. 2 ,KCN,NaH / Br 2 and KCN, so these routes are not suitable for industrial scale-up production

Method used

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  • Preparation of 6-(3,4-diamino phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-ketone key intermediate of 2-(4-methoxyphenyl)-5(6)-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl)benzimidazole
  • Preparation of 6-(3,4-diamino phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-ketone key intermediate of 2-(4-methoxyphenyl)-5(6)-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl)benzimidazole
  • Preparation of 6-(3,4-diamino phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-ketone key intermediate of 2-(4-methoxyphenyl)-5(6)-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl)benzimidazole

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Embodiment

[0022] 1. Preparation of 4-(4-acetylamino-3-nitrophenyl)-3-methyl-4-oxobutanoic acid (formula II)

[0023] 140 grams of nitric acid (93mL) and 20 grams of sulfuric acid (11mL) were mixed and placed in a reaction flask to cool below -5°C, and 4-(4-acetylaminophenyl)-3-methyl-4-oxobutyric acid (Formula I) (31g, 0.124mol) was slowly added in batches, and the temperature of the system was controlled at -5°C during the addition process (3-5 grams each time, with an interval of about 15 minutes). After feeding, the system was stirred at about 0°C for 4 hours, and then the reaction solution was slowly added to the solution made of 300mL water and 90g NaCl (cooled to about 0°C in advance), and fully stirred after adding. The system was slowly raised to room temperature, and then the reaction solution was extracted with ethyl acetate (300 mL), and the organic phase was separated. The aqueous phase was further extracted with ethyl acetate (360 mL). Combine the organic phases, wash the...

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Abstract

The invention relates to preparation of a 6-(3,4-diamino phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-ketone key intermediate for synthesizing 2-(4-methoxyphenyl)-5(6)-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl)benzimidazole. The technology is short in synthetic route and easy to operate and has an industrialized enlarged production prospect.

Description

technical field [0001] The invention relates to the preparation of a key intermediate of pimobendan---6-(3,4-diaminophenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one. Background technique [0002] Pimobendan (Pimobendan, UD-CG115BS, Acardi, CAS: 74150-27-9) was developed by Boehringer Ingelheim, Germany, and was first listed in Japan in 1994 as a cardiotonic drug with vasodilation. Phosphodiesterase inhibitors are mainly used clinically for the treatment of heart failure. The mechanism of action of this drug is different from that of traditional cardiotonic drugs, and its positive inotropic effect is mainly attributed to the enhancement of the effect of cardiac contractile proteins on Ca 2+ Sensitivity and inhibition of phosphodiesterase III (PDE III), is the first calcium sensitizer drug on the market. Studies have shown that the drug has a strong vasodilator effect and anti-platelet aggregation effect, almost no side effects, can also treat chronic heart insufficiency and ...

Claims

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Application Information

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IPC IPC(8): C07D237/04C07D403/04
CPCC07D237/04C07D403/04
Inventor 邱小龙张新刚彭陟辉王东辉邹平张义森邓贤明游正伟江中兴胡林曹雷陈俊
Owner SOUTHEAST UNIV
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