clear yellow to light brownish liquid
3,4-Dethoxy-3-cyclobutene-1,2-dione is used as a starting material for synthesis of furanones and quinones. It undergoes ethoxy substitution with amines and unsaturated organosilanes.
Diethyl squarate is an intermediate for pharma products, for photochemicals used in the dry-view process, in synthesis of photosensitive squaraine dyes (eg. laser dyes used in CD-Rom) and as intermediate for functional polymers.
The reaction of 3,4-diethoxy-3-cyclobutene-1,2-dione (squaric acid diethyl ester) with glycosylamines (formed by reducing oligosaccharides) was studied. The derivatives formed were linked to amino-functionalized lipids, solids or proteins.