Microwave-assisted high-efficiency method for synthesizing 5-cyanouracil

The invention relates to a microwave-assisted high-efficiency method for synthesizing 5-cyanouracil, which comprises the following steps: carrying out microwave radiation on urea, malononitrile and triethyl orthoformate at the microwave reaction temperature of 60-80 DEG C under the microwave power of 500W under atmospheric pressure for 8-20 minutes, and filtering the residual triethyl orthoformate out of the reaction system to obtain a dicyan intermediate I; dissolving the obtained solid in a sodium ethylate 1.0-2.0 mol/L solution, carrying out radiation reaction at the microwave reaction temperature of 30-50 DEG C under the microwave power of 300W under atmospheric pressure for 30-50 minutes, adding activated carbon for decolorization, filtering, and acidifying the filtered precipitate with glacial acetic acid to obtain an intermediate II; and adding 2.5-3.0 mol/L dilute hydrochloric acid into the intermediate II, carrying out radiation at the microwave reaction temperature of 80-100 DEG C under the microwave power of 500W under atmospheric pressure for 30-50 minutes, cooling, and filtering to obtain the 5-cyanouracil.