Synthesis method for industrially producing sildenafil amide intermediate

The invention discloses a synthesis method for a sildenafil amide intermediate 1-methyl-3-propyl-4-nitropyrazole-5-formamide, and the synthesis method is easy and convenient to operate and suitable for industrial production. According to the method, harm of thionyl chloride to instruments and equipment is specifically reduced, appropriate solvent is found to protect acyl chloride, and the yield is greatly increased. The method is high in safety, easy and convenient to operate and little in environmental pollution, the used solvent can be recycled, and the industrial cost is greatly reduced.