Amines, diazo transfer reaction, synthesis

Reactions of this type were first studied by Curtius and co-workers . For example, diethyl malonate and /(-toluenesulphonyl azide reacted in the presence of cold sodium ethoxide to give the sodium salt of the 5-hydroxytrizizole (296) . Acidification gave the 5-triazolone (297) which isomerized to the diazo compound (298) (overall yield 90%). (The same product could be obtained in 85% yield without base by heating the azide and malonate at 100° and a pressure of 20 mm) . This reaction provided the basis for the so-called diazo-transfer reaction, an extremely useful method of synthesizing diazo compounds, which has been reviewed. The reaction has been formulated as shown in equation (134), and has been extended to the synthesis of azides by a diazo transfer to amine anions/i-Toluenesulphonyl azide reacts with hydrazone... 

Azide synthesis (2, 415). In the definitive paper3 describing the conversion of primary amines into azides by a diazo transfer reaction, methyllithium is preferred to methylmagnesium chloride as the base. The reaction has been extended to hydrazones. Thus, when the hydrazones of benzophenone, fluorenone, and acetophenone are treated with methylmagnesium chloride and then with tosyl azide, the corresponding diazoalkanes are obtained in about 20% yield. 

Regitz diazo transfer reactions have been reviewed previously.1-3 The following two main routes have been known for the synthesis of diazo compounds (1) diazotization of amines, oximes, nitrosoamines, and hydrazones (2) transfer of the diazo function from tosyl or mesyl azides to active methylene compounds. 

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