First Synthesis of Highly Chemiluminescent Benzofuran‐2(3H)‐ones Bearing a Urea Substructure

• Published in: Helvetica chimica acta Vol. 102; no. 6
• Main Authors: Krieg, Reimar, Hoffmann, Birgit, Weiß, Dieter, Biskup, Christoph
• Format: Journal Article
• Language: English
• Published: Zürich Wiley Subscription Services, Inc 01.06.2019
• Subjects: Bearing; Benzofuran; Chemiluminescence; Decay rate; Derivatives; Ethyl carbamate; Hydrogen peroxide; Organic chemistry; Phenols; Substitution reactions; Substructures; Urea; Ureas
• ISSN: 0018-019X; 1522-2675
• DOI: 10.1002/hlca.201800243

A series of benzo[b]furan‐2(3H)‐ones (coumaran‐2‐ones) bearing a urea substructure, namely derivatives of 3‐(aminocarbonylamino)benzo[b]furan‐2(3H)‐one, was prepared for the first time. The accessibility of these compounds through an electrophilic α‐amidoalkylation approach of phenols (Tscherniac–Einhorn reaction) in the key step as well as the chemiluminescence (CL) properties of the desired compounds are strongly dependent on the substitution patterns at the urea moiety. Competing reaction pathways are discussed and an improved one pot synthetical approach of also general interest is presented. In conclusion, especially N,N‐dialkylaminocarbonylamino‐derivatives of benzo[b]furan‐2(3H)‐ones exhibit a strong flash like blue CL upon treatment with bases such as 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in the presence of oxygen or hydrogen peroxide. Comparative physico‐chemical investigations revealed that novel compounds outperform their urethane‐analogues in terms of CL‐intensity and the speed of the decay making them potentially useful as new tools for CL‐based applications on the short time scale.