Step 1: condensation reaction between 4-nitrophenylhydrazine and ethyl acetoacetate to produce 3-methyl-1 - (4-nitrophenyl) - 1H-pyrazol-5 (4H) - on.
Giai đoạn 1: ngưng tụ giữa 4 - nitrophenylhydrazin và ethyl acetoacetat tạo ra 3-methyl-1-(4-nitrophenyl)-1H-pyrazol-5(4H)-on.