In the extended family of glycoluril derivatives, there is a member with a highly symmetric chemical structure and exceptionally rich reactivity - tetramethylol glycoluril. Its CAS number is 5395-50-6, its molecular formula is C₈H₁₄N₄O₆, and its molecular weight is 262.22 Daltons. Its full systematic name is tetrahydro-1,3,4,6-tetrakis(hydroxymethyl)imidazo[4,5-d]imidazole-2,5(1H,3H)-dione.
Structurally, tetramethylol glycoluril takes the bicyclic glycoluril core as its skeleton and "grafts" one reactive methylol group (–CH₂OH) onto each of the four nitrogen atoms. These four methylol groups, like four extended "reactive arms" evenly distributed around the molecule, endow the entire molecule with outstanding chemical reactivity and crosslinking capability. In terms of physical properties, tetramethylol glycoluril is a white to off-white crystalline powder at room temperature, with a melting point of 137–138 °C, a boiling point as high as approximately 624 °C, and a density of about 1.697 g/cm³. It is slightly soluble in chloroform, DMSO, and methanol (with the aid of ultrasonication) and exists in a non-ionic, uncharged form.
It is precisely this "four-armed" structure that allows tetramethylol glycoluril not only to participate in a variety of chemical reactions on its own but also to be further derivatized into even more functionalized molecules, such as tetramethoxymethyl glycoluril. It can be rightly called a pivotal "central hub" within the glycoluril family.