合成路线1

Title compound has been prepared by several routes: Condensation of 4'-methoxyacetophenone (I) with diethyl oxalate in the presence of lithium hexamethyldisilazide provided lithium ethyl 4-methoxybenzoylpyruvate (II). Subsequent condensation of (II) with 4-methoxyphenylhydrazine hydrochloride (III) yielded diarylpyrazole (IV). This was coupled with bromide (V) in the presence of n-BuLi to afford ketone (VI). The oxazoline ring of (VI) was then hydrolyzed to carboxylic acid (VII) by successive treatments with HCl and with NaOH. Activation of the carboxylic acid of (VII) as the mixed anhydride with ethyl chloroformate, followed by treatment with gaseous ammonia provided amide (VIII). The required dimethyl ketal was finally introduced in (VIII) by means of trimethyl orthoformate in MeOH in the presence of p-TsOH.