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.

以水为介质,方酸与衍生物顺利生脱水缩,一类方酸单酰胺化物——氨甲酰类氮氧方酸3。