35 results about "P-bromophenol" patented technology

A method for preparing hydroxyaromatic compounds brominated in the para-position, such as p-bromophenol, is disclosed. The method yields overall high process selectivity through isomeric equilibration and separation of the brominated products, thereby eliminating the need for high para selectivity in the products of catalytic oxybromination reactions of hydroxyaromatic compounds using oxygen, a bromine source, and an acidic medium in the presence of a metal catalyst. Furthermore, the invention provides an efficient method for recycling the metal catalyst, as well as reagents used in the bromination, to further reactions.

The invention discloses a synthesis method of 2,5-dibromoiodobenzene, comprising the following steps: S1, synthesis of 2-nitro-4-bromophenol; S2, synthesis of 2-amino-4-bromophenol; The synthesis of S3, 2-iodine-4-bromophenol; the synthesis of S4, 2,5-dibromoiodobenzene: 2-iodine-4-bromophenol is placed in a chemical reaction kettle, and then dioxane solvent is added, And stir at room temperature, gradually add phosphorus tribromide in this process, reactant is subjected to vacuum fractionation, collects 130-140 ℃, 3.25-3.45kPa fraction promptly obtains 2,5-dibromoiodobenzene, the present invention Utilize p-bromophenol as raw material, carry out the preparation of 2-nitro-4-bromophenol by p-bromophenol, then further prepare 2-amino-4-bromophenol, and then turn into 2-iodo-4-bromophenol , finally synthesized 2,5-dibromoiodobenzene, realized the synthesis and preparation of 2,5-dibromoiodobenzene in another way, expanded the preparation raw materials of 2,5-dibromoiodobenzene, and simultaneously the raw material parabromo Phenol is low in cost and large in quantity, making it convenient for industrial production.

The invention provides a preparation method of an Eltrombopag intermediate and a preparation method of Eltrombopag diethanolamine salt, which relate to the technical field of medicinal chemistry. The preparation method of the Eltrombopag intermediate uses p-bromophenol as a raw material, and the nitration reaction does not have the problem of poor selectivity. After iodination, the yield of the coupling reaction between the compound of the intermediate formula (I) and phenylboronic acid is relatively high. Subsequent reduction reaction is carried out, the debromination reaction is complete, the yield is over 90%, and the purification is relatively simple. The synthesis yield of the compound of formula (I) is high and the operation is simple. Through the above improvements, the yield of the key compound of formula (I) is high, the follow-up treatment operation is simple, and the process is easy to scale up production. The yield of the whole synthesis process of Eltrombopag diethanolamine salt is 48.1%. The operation is simple, the three wastes are less, and it is suitable for scale-up Production.