摘要:
The present invention relates to a continuous method for the preparation of (S)-2-acetyloxypropionic acid from an aqueous solution of lactic acid and acetic anhydride, in acetic acid. (S)-2-acetyloxypropionic acid is used for the preparation of (S)-2-acetyloxypropionic acid chloride, an essential intermediate compound for the preparation of lopamidol and has to be industrially produced with high purity and suitable quality for producing lopamidol according to the Pharmacopoeia requirements. The continuous process according to the invention, comprises therefore also the chlorination steps of (S)-2-acetyloxypropionic acid with thionyl chloride to give the corresponding (S)-2-acetyloxypropionic acid chloride which is further distilled to give the suitable purity characteristics for its use for the preparation of non-ionic iodinated contrast agents as lopamidol.
摘要:
The present invention relates to a continuous method for the preparation of (S)-2-acetyloxypropionic acid from an aqueous solution of lactic acid and acetic anhydride, in acetic acid. (S)-2-acetyloxypropionic acid is used for the preparation of (S)-2-acetyloxypropionic acid chloride, an essential intermediate compound for the preparation of lopamidol and has to be industrially produced with high purity and suitable quality for producing lopamidol according to the Pharmacopoeia requirements. The continuous process according to the invention, comprises therefore also the chlorination steps of (S)-2-acetyloxypropionic acid with thionyl chloride to give the corresponding (S)-2-acetyloxypropionic acid chloride which is further distilled to give the suitable purity characteristics for its use for the preparation of non-ionic iodinated contrast agents as lopamidol.
摘要:
The present invention relates to a method for the acetylation of an aqueous solution of lactic acid to (S)-2-acetyloxypropionic acid. The process comprises in particular removing water from the solution of lactic acid and reacting lactic acid with acetic anhydride in the presence of acetic acid.
摘要:
The present invention generally refers to a process for the preparation of L- thyroxine derivatives. More in particular, the present invention relates to a iodination reaction of an aromatic derivative with an appropriate iodinating agent, so to afford the related iodinated compound as disodium salt, which may represent a useful intermediate for the synthesis of the L-thyroxine mono-sodium salt, and the free form thereof.