Pyrrole-2-carboxylic ester chlorination

Pyrrole-3-carboxylic acid, l-benzoyl-5-bromo-2,4-dimethyl-ethyl ester chlorination, 4, 271... [Pg.818]

When an ester reacts with a ring-carbon atom in the presence of a Friedel-Crafts catalyst, a cyclic ketone (or its tautomeric enol) is usually formed (p. 378), but in boiling phosphorus oxychloride, the oxygen function may be replaced by a chlorine atom [2634]. A carboxylic acid may react with a suitably placed ring-carbon by heating with either PPA or phosphorus oxychloride [2127] phosphorus pentoxide in xylene is also effective [2347]. When an electron-rich ring such as that of pyrrole is available, heating with acetic anhydride for I h suffices [3913]. [Pg.461]