(Dimethylaminomethylene-aminomethylene)dimethylammonium chloride

Gold′s Reagent was used in the synthesis of 4-hydroxyquinazoline by reacting with ortho aminobenzoic acids.

[[[(Dimethylamino)methylene]amino]methylene]dimethylammonium Chloride is a β-dimethylaminomethylenating agent for ketones and amines; yields enamino derivatives of esters and lactones; converts Grignard reagents to aldehydes.

The Preparative Method of [[[(Dimethylamino)methylene]amino]methylene]dimethylammonium Chloride: a 1 L, one-necked, round-bottomed flask is equipped with a Claisen adapter, mechanical stirrer, reflux condenser, and mineral oil bubbler. The flask is charged with cyanuric chloride (73.8 g, 0.4 mol) (Caution: cyanuric chloride is a lachrymator and causes burns on contact with the skin), N,N-Dimethylformamide (175.4 g, 2.4 mol) and 1,4-dioxane (100 mL). The resulting solution is stirred and heated at 85 °C for 2-3 h while a considerable amount of carbon dioxide is evolved. When gas evolution is minimal, the reaction mixture is allowed to cool to room temperature; the product rapidly solidifies (eq 1). The flask which contains the solid product is connected to an isopropyl alcohol/dry ice trap and the solvent is removed by evacuating the system to approximately 0.05 mmHg. The crude product weighs 186-187 g (95% yield). Another method of isolating the product is by rapid filtration and washing with acetone.

Gold's reagent is very hygroscopic and should be handled under a moisture-free environment. If kept dry, it has a substantial shelf-life. Store in desiccator over anhydrous calcium sulfate.