| 摘要 |
<p>Disclosed is a process for preparing a compound having formula (I) wherein R1 is selected from the group consisting of: alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, and cycloalkyalkyl, R1 being optionally substituted by substituents selected from halo, -OH, alkyl, alkoxy, or -CF¿3?, said process comprising the following steps: (a) reacting a ketone having formula (A) with a carbanion having formula (B) wherein R?1¿ is defined above, and R?2 and R3¿ are independently selected from the group consisting of -OR?A and -RA¿; wherein RA is alkyl, phenyl, substituted phenyl, cycloalkyl, substituted cycloalkyl, cycloalkylalkyl, or substituted cycloalkylalkyl; (b) treating the reaction mixture from step (a) with a protonating agent to form a β-hydroxy intermediate having formula (C) wherein R?1, R2 and R3¿ are as defined above; and (c) thermally decomposing the β-hydroxy intermediate to form the compound of formula (I). The compounds made by this process have antihistaminic activity, e.g., loratadine. Also disclosed is a process for preparing descarboethoxyloratadine, by carrying out the process above, and converting the product to descarboethoxyloratadine. Also disclosed are novel intermediates having formula (II) and (III) wherein R?1, R2 and R3¿ are as defined above.</p> |
