Optimization of the reaction conditions for the synthesis of 2,3,5-trimethylpyridine from 3-amino-2-methylpropenal and methylethylketone

The influence of temperature, reaction time, and type of the catalyst on the yield of the 2,3,5-trimethylpyridine (collidine) from 3-amino-2-methylpropenal and methylethylketone was investigated. 3-Amino-2-methylpropenal was synthesized from 3-ethoxy-2-methylacrolein previously synthesized from methylmalondialdehyde tetraethyl acetal, obtained from triethyl orthoformate and propenyl ether. The optimal conditions for the investigated synthesis were temperature of 150 °C, reaction time 24 h, and the CH3COOH/pTsOH catalyst. This synthesis is the first successful attempt to synthesize 2,3,5-trimethylpyridine in an acid medium.