Photo-Induced N–N Coupling of <i>o</i>-Nitrobenzyl Alcohols and Indolines To Give <i>N</i>-Aryl-1-amino Indoles

Abstract

A novel method to synthesize <i>N</i>-aryl-1-amino indoles was established by the photoinduced N-N coupling reaction. This protocol is by treatment of <i>o</i>-nitrobenzyl alcohols and indolines in the presence of TEAI and acetic acid with a 24 W ultraviolet (UV) light-emitting diode (LED) (385-405 nm) irradiation. The products bearing an aldehyde group can be further transformed to fluorescent probes based on Rhodamine 6G derivative <b>11</b>, which shows a high specificity and sensitivity for Fe³⁺.