反应详情

According to scheme (b), the precursor of formula IIb is decarboxylated under acidic, mild conditions. For example, 5-(p-chlorobenzoyl)-3-hydroxycarbonyl-4-methoxy-1-methylpyrrole-2-acetic acid or its corresponding di(t-butyl) ester is treated with refluxing trifluoroacetic acid to afford 5-(p-chlorobenzoyl)-4-methoxy-1-methylpyrrole-2-acetic acid. Other acids may also be used. For example, those listed below in Table III.