A kind of monosubstituted squaric amide ——mono carbamoyl amide of squaric acid 3(MCASAQ) was prepared by the condensation of squaric acid (SQ) with urea or its derivatives in water.

以水为介,与脲及其衍生物顺利生脱水缩合,合成了一单酰胺化合物——氨甲酰氮氧3。