Synthesis of Imidazoles from Fatty 1,2-Diketones

Unsaturated vegetable oils and their corresponding fatty acid derivatives constitute interesting renewable platforms for the preparation of heterocycles, notably through the formation of oxygenated intermediates. In this work, fatty imidazoles were prepared from the corresponding 1,2-diketones through Debus-Radziszewski reaction. The reaction was optimized under microwave irradiation using a 1,2-diketone derived from methyl oleate and ammonium acetate as a nitrogen source. Using benzaldehyde as a model substrate, the reaction occurs at 180 degrees C for 5 min and the desired imidazole was formed in 96 % GC yield. A range of aldehydes was tested under the optimized conditions and the corresponding imidazoles were obtained in 33-99 % isolated yields (20 examples).

Automated summary

Unsaturated vegetable oils were used to prepare fatty imidazoles through the Debus-Radziszewski reaction, which was optimized under microwave irradiation. The reaction yielded the desired imidazoles at a high GC yield of 96% when using benzaldehyde as a model substrate at 180 degrees C for 5 minutes. Various aldehydes were tested under the optimized conditions, resulting in isolated yields of 33-99% for the corresponding imidazoles.