139756-03-9Relevant articles and documents
Improved synthesis process of sildenafil
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Paragraph 0039-0045, (2021/06/21)
The invention discloses an improved synthesis process of sildenafil, belonging to the technical field of preparation of drug intermediates. In the process, high-concentration chlorosulfonic acid is prevented from being used as a reaction solvent and reagent, and 3-5 equivalent chlorosulfonic acid is used as a reaction reagent. Compared with the prior art, the process has the characteristics of economical performance, environmental protection, safety and the like, for example, equipment cannot be corroded, the post-treatment of reaction becomes simpler, the solvent is single and can be reused, product purity is high, and the like.
Preparation method of sildenafil
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Paragraph 0038-0040; 0043-0045; 0048-0050; 0053-0055; 0058, (2020/10/04)
The invention provides a preparation method of sildenafil. The preparation method comprises the following steps: dissolving a compound III in an organic solvent I, adding a compound II for amidation reaction, washing and drying to obtain a compound IV; directly adding the solution obtained in the step S1 into a chlorosulfonic acid-thionyl chloride mixture for chlorosulfonation reaction without separation and purification, pouring ice water after the reaction is finished, layering, taking an organic phase, washing and drying to obtain a compound V; adding the compound V obtained in the S2 intoN-methyl piperazine, carrying out N-sulfonation reaction for 0-4 hours, concentrating, adding alkali and an organic solvent II, heating to carry out cyclization reaction for 2-6 hours, adding water for cooling, adding hydrochloric acid for acidification, and filtering to obtain a target compound I. A continuous method is adopted for synthesis, and the production efficiency is improved.
Preparation method of sildenafil citrate
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Paragraph 0031; 0032, (2018/06/16)
The invention belongs to the field of chemical drugs, and in particular relates to a preparation method of sildenafil citrate. The invention provides the preparation method of sildenafil citrate. Thepreparation method comprises the following steps: a) adding a compound of a structure as shown in a formula (I) and thionyl chloride into chlorosulfonic acid, and carrying out a sulfonation reaction to generate a compound of a structure as shown in a formula (II); b) dissolving the compound of the structure as shown in the formula (II) in dichloromethane and adding N-methyl piperazine to carry outa substitution reaction at 20-30 DEG C to obtain sildenafil; and c) adding citric acid into a sildenafil aqueous solution to adjust the pH value for a salt forming reaction so as to obtain the sildenafil citrate. Experimental results verify that the sildenafil citrate prepared by the preparation method is high in yield and high in purity.