Polyfunctional imidazoles: X. Synthesis of 4-chloro-5-(2-nitroalkenyl)-1H-imidazoles and their reaction with 5-methyl-2,4-dihydro-3H-pyrazol-3-one

Condensation of 1-aryl-4-chloro-1H-imidazole-5-carbaldehydes with nitroalkanes in the presence of anhydrous ammonium acetate gave 4-chloro-5-(2-nitroalkenyl)-1H-imidazoles which reacted with 5-methyl-2,4-dihydro-3H-pyrazol-3-one according to the Michael addition scheme with formation of 4-[1-(4-chloro-1H-imidazol-5-yl)-2-nitroalkyl]-5-methyl-1H-pyrazol-3-ols.