Diacetyl-o-toluidine

Boil a mixture of 10 g. (10 ml.) of o-toluidine and 38 g. (35 ml.) of acetic anhydride in a 75 or 100 ml. Claisen flaak fitted with a reflux condenser (Fig. Ill, 28, 1, but with trap replaced by a calcium chloride or cotton wool guard tube) for 1 hour. Arrange the flask for distillation under reduced pressime (compare Fig. II, 20,1) and distil acetic acid and the excess of acetic anhydride pass over first, followed by the diacetyl derivative at 152-153°/20 mm. some mono-acetyl-o-toluidine (1 - 2 g.) remains in the fiask. The yield of diacetyl-o-toluidine is 14-15 g. it is a colourless, somewhat unstable liquid, which slowly solidifies to yield crystals, m.p. 18°. 

To prepare the (mono-) acetyl-o-toluidine, warm a mixture of 5 g. 

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The production of diacetyl derivatives is facilitated by the presence of substituents in the ortho position thus an excellent yield of diacetyl-o-toluidine results when o-toluidine is heated with an excess of the reagent ... 

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