2,5-Dimethyl (CAS NO.: ), which is known as Pyrrole, 2,5-dimethyl-, could be produced through the following synthetic route.

In a 500-cc. Erlenmeyer flask, fitted with an air-cooled reflux condenser of large bore, are placed 100 g. (0.88 mole) of acetonylacetone and 200 g. (1.75 moles) of ammonium carbonate, in lumps. The mixture is heated in an oil bath at 100° until effervescence stops; this requires sixty to ninety minutes. The air-cooled condenser is replaced by a water-cooled condenser of large bore, and the mixture is refluxed gently at 115° (bath temperature) for thirty minutes longer. The mixture is cooled, and the upper, yellow layer of the pyrrole is separated. The lower layer is extracted with 15 cc. of chloroform, which is added to the crude pyrrole. The whole is dried over anhydrous calcium chloride, in a tightly stoppered container which has been swept out with nitrogen beforehand.

The material is transferred to a modified Claisen flask having a fractionating side arm, and the chloroform is distilled completely under reduced pressure (without being condensed). The dimethylpyrrole is collected at 51–53°/8 mm. or 78–80°/25 mm.; only a small residue (4–5 g., b.p. 80–85°/25 mm.) remains. The product weighs 68–72 g. (81–86 per cent of the theoretical amount) and is quite pure; it should be stored in an inert atmosphere in a tightly sealed, dark glass container.