13676-47-6Relevant articles and documents
Preparation method of 2-aminobenzoxazole compound
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, (2022/01/20)
The present invention relates to a method for preparing a 2-aminobenzoxazole compound. Comprising the following steps: (1) condensation reaction: taking o-aminophenol and nitrobenzoyl chloride compounds as raw materials, synthesizing amide intermediates in an alkaline solution system. The highly selective double-base combination system does not react with the raw material and can neutralize the acid gas generated by the reaction; (2) Cyclization reaction: acid is added to the condensation reaction solution as a catalyst, and 2-nitrobenzoxazole compounds are generated after dehydration. The solid super acid catalyst used is efficient and easy to separate and recycle; (3) hydrogenation hydrogenation reaction: 2-nitrobenzoxazole compounds are catalyzed to obtain 2-aminobenzoxazole compounds. The bi-alkali system and solid super acids used in the present invention are highly selective, product quality and yield are high. The operation is safe and simple, the raw material cost is low, in line with the green and environmentally friendly production concept, which is conducive to industrial production.
Preparation method of 2-(aminophenyl)-5-aminobenzoxazole
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, (2019/12/29)
The invention discloses a preparation method of 2-(aminophenyl)-5-aminobenzoxazole. The preparation method concretely comprises the following steps: (1) condensing sodium 2-amino-4-nitrophenolate andnitrobenzoyl chloride to obtain an ester intermediate; (2) cyclizing the ester intermediate under the catalysis of a strong acid to obtain 2-(nitrophenyl)-5-nitrobenzoxazole; and (3) hydrogenating the2-(nitrophenyl)-5-nitrobenzoxazole under the catalysis of Pd/C to obtain the 2-(aminophenyl)-5-aminobenzoxazole. The sodium 2-amino-4-nitrophenolate and nitrobenzoyl chloride are condensed to only generate a hydroxyl-substituted acylation intermediate (that is the ester intermediate), and the amino part does not react with the nitrobenzoyl chloride, so no amide impurities are generated, the reaction selectivity is high, the yield of condensation and cyclization is up to about 90%, and the purity of the above nitro compound is about 99%.
Preparation method of diamido nitrogen-containing aromatic heterocycle compound
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Paragraph 0082; 0083; 0084, (2018/10/19)
The invention relates to the technical field of synthesis of compounds, in particular to a preparation method of diamido nitrogen-containing aromatic heterocycle compound. The preparation method includes mixing a compound having the structure as shown as the formula (I) with inorganic acid, reacting to obtain water-soluble organism, performing reduction reaction with a reducing agent sulfide to effectively reduce nitro-organism into amino-compounds, performing neutral reaction with alkali liquor so as to obtain the diamido nitrogen-containing aromatic heterocycle compound having the structureas shown as the formula (II) and having high yield and purity. The preparation method is simple and environmental friendly, is low in cost, needs mild reaction conditions, and is suitable to be popularized and applied in scale. According to tests, the yield of the diamido nitrogen-containing aromatic heterocycle compound prepared by the method is not lower than 90%, and even can reach 96%, and itspurity can reach 99.9%.