Abstract: The invention pertains to a process for preparing stable anhydrous Ropivacaine hydrochloride, the process involving preparing Ropivacaine hydrochloride from Ropivacaine base, wherein Ropivacaine base is provided having a chiral purity of more than 95%, and wherein the isolation involves the use of isopropanol and hydrochloride, and is performed under water-free conditions. Ropivacaine base may be provided at high chiral purity by N-propylating L-pipecolic acid 2,6-xylidide hydrochloride in the presence of a phase transfer catalyst, wherein the reaction involves a biphasic reaction mixture containing an alkaline aqueous phase and an organic phase. The invention further pertains to stable anhydrous Ropivacaine hydrochloride obtainable by the above process.

Abstract: The invention relates to a preparation process for 2-substituted 5-formylimidazoles, wherein the intermediate high-pressurized synthesis of an 2-substituted 4-hydroxymethylimidazole as known in the art is conveniently avoided, and wherein much higher yields are obtained. Instead, it is proposed to prepare such 2-substituted 5-formylimidazoles via a one-pot synthesis involving 2-substituted 4-chloro-5-formylimidazole, thereby employing an additional hydrodehalogenation step. Moreover, it is found that the yield and purity of 2-substituted 4-chloro-5-formylimidazole itself can be significantly improved using a triflate catalyst in the preparation process.