14205-46-0Relevant articles and documents
Nimodipine impurity IV reference substance as well as preparation method and application thereof
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Page/Page column 0051; 0053-0054, (2020/11/22)
The invention discloses a nimodipine impurity IV reference substance and a preparation method thereof. The method includes the steps that diketene, ethyl alcohol and triethylamine are taken and addedinto a container to be heated and cooled, reaction liquid is washed with water, washing liquid is discarded, anhydrous sodium sulfate is added and placed overnight, filtrate is obtained after filtration, ammonia gas is introduced into the filtrate until the filtrate is saturated, and the nimodipine impurity IV reference substance is obtained; and after the reaction is finished, m-nitrobenzaldehyde, methoxyethyl acetoacetate and ethanol are added, heating refulx is performed, the mixture is cooled and filtered, the solvent is removed through volatilization in a water bath to obtain a yellow viscous liquid, and recrystallization is carried out to obtain a yellow acicular crystal, namely the nimodipine impurity IV reference substance. The invention also discloses an application of the nimodipine impurity IV reference substance in nimodipine tablet consistency evaluation. According to the preparation method, the impurity IV can be prepared in a general analysis laboratory, special preparation equipment is not needed, the operation is simple, the purity of the obtained impurity reference substance can reach 98.4%, the purity requirement of the reference substance is met, and the preparation method can be used for consistency evaluation of the variety.
Synthesis method of isopropyl 3-aminocrotonate
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Paragraph 0022; 0024; 0026; 0028; 0030-0032; 0034; 0036, (2018/06/26)
Isopropyl 3-aminocrotonate is an important chemical intermediate and has excellent industrial production value; however, methods in the prior art have problems of incomplete raw material conversion, difficulty of raw material removal, low product content and low yield; the method in the invention includes steps of with isopropyl acetoacetate and ammonium salt as raw materials, mixing the raw materials and performing a heating reaction, and when the isopropyl acetoacetate is reacted completely, separating the product to prepare the isopropyl 3-aminocrotonate. The method has simple operation, more completely converts the raw materials, and is high in product purity.
Preparation method of azelnidipine
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Paragraph 0016, (2017/03/08)
The invention relates to a preparation method of azelnidipine, which comprises the following steps: carrying out Knoevenagel reaction on cyanoacetic acid and m-nitrobenzaldehyde used as starting materials to generate a compound 1; hydrolyzing cyano group of the compound 1 to generate a compound 2; carrying out esterification on the compound 2 and 1-diphenylmethyl-3-azetidin-ol under the action of DCC (N,N'-dicyclohexylcarbodiimide) to generate a compound 3; carrying out Hantzsch cyclization on the compound 3 and isopropyl 3-aminocrotonate under alkaline conditions to generate an azelnidipine crude product; and refining the crude product to obtain the azelnidipine fine product. The method is simple to operate and suitable for industrial production; and the reaction product is easy to separate.