An investigation into the synthesis of azido-functionalised coumarins for application in 1,3-dipolar %26quot;click%26quot; cycloaddition reactions

作者：Evans Vikki; Duncanson Philip; Motevalli Majid; Watkinson Michael

来源：Dyes and Pigments, 2016, 135: 36-40.

DOI：10.1016/j.dyepig.2016.06.028

• Coumarin
• Fluorescent dye
• Click chemistry
• Azide

A range of reported methods have been assessed for the synthesis of two coumarin fluorophores containing azides, la and 2, for subsequent "click" modification. In the case of la reported methods were successfully applied, but the resulting azide proved to be rather unstable and appears more suited to in situ generation and conversion to the "click" triazole. In the case of 2, reported methods for the synthesis of precursor 5 were ineffective in two cases and resulted in either no bromination a-to the carbonyl or the formation of multiple unwanted side-products, some of which were isolated, 6-13. The use of CuBr2 in excess or Br-2 in 50% HBr in acetic acid did result in the isolation of 5, which could be efficiently converted to 2 using excess NaN3 in THF.

• 出版日期2016-12