Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Chemical compound
Squaramide is the organic compound with the formula O2C4(NH2)2. Not an amide in the usual sense, it is a derivative of squaric acid wherein the two OH groups are replaced by NH2 groups. Squaramides refer to a large class of derivatives wherein some of the H's are replaced by organic substituents. Exploiting their rigid planar structures, these compounds are of interest as hydrogen-bond donors in supramolecular chemistry and squaramide catalysis.[1] Squaramides exhibit 10-50x greater affinity for halides than do thioureas.[2] Squaramides also find application in medicinal chemistry, metabolomics and material science due to their ability to selectively conjugate amines[3][4]
Squaramide is prepared by ammonolysis of diesters of squaric acid:[5][6]
O2C4(OEt)2 + 2 NH3 → O2C4(NH2)2 + 2 EtOH
N-Substituted squaramides are prepared similarly, using amines in place of ammonia.
^ abNathalie Busschaert; Isabelle L. Kirby; Sarah Young; Simon J. Coles; Peter N. Horton; Mark E. Light; Philip A. Gale (2012). "Squaramides as Potent Transmembrane Anion Transporters". Angew. Chem. Int. Ed. 51 (18): 4426–4430. doi:10.1002/anie.201200729. PMID 22461434. S2CID 34164978.
^Lin, Weifeng; Yang, Zhen; Kaur, Amanpreet; Block, Annika; Vujasinovic, Miroslav; Löhr, J.-Matthias; Globisch, Daniel (2021). "Squaric acid as a new chemoselective moiety for mass spectrometry-based metabolomics analysis of amines". RSC Chemical Biology. 2 (5): 1479–1483. doi:10.1039/D1CB00132A. ISSN 2633-0679. PMC 8496035. PMID 34704052.
^Wurm, Frederik R.; Klok, Harm-Anton (2013). "Be squared: expanding the horizon of squaric acid-mediated conjugations". Chemical Society Reviews. 42 (21): 8220–8236. doi:10.1039/c3cs60153f. ISSN 0306-0012. PMID 23873344.
^Storer, R. Ian (2013). "Squaramide". e-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn01531. ISBN 978-0-471-93623-7.
^Ian Storer, R.; Aciro, Caroline; Jones, Lyn H. (2011). "Squaramides: Physical properties, synthesis and applications". Chemical Society Reviews. 40 (5): 2330–2346. doi:10.1039/c0cs00200c. PMID 21399835.
Squaramide is the organic compound with the formula O2C4(NH2)2. Not an amide in the usual sense, it is a derivative of squaric acid wherein the two OH...
Within the area of organocatalysis, squaramide catalysis describes the use of squaramides to accelerate and stereochemically alter organic transformations...
112.0273 u) may refer to: Cellocidin (2-butynediamide) Maleic hydrazide Squaramide Uracil This set index page lists chemical structure articles associated...
charged lipid, neutral ionizable amino lipids were developed. A novel squaramide lipid (that is, partially aromatic four-membered rings, which can participate...
as an intermediate in the synthesis of perzinfotel.[citation needed] Squaramides are prepared by displacement of alkoxy or chloride groups from C4O2X2...
hydrogen bonds provided by coplanar amino substituents in the (thio)urea. Squaramide catalysts engage in double H-bonding interactions and are often superior...