Synthesis of New BAPTA Calcium Chelators

Abstract

A series of new 1,2-bis-(2-aminophenoxyethane) N,N,N′,N′-tetraacetic acid (BAPTA) chelators were designed and synthesized to form novel and improved fluorescent indicators. Substituted 2-nitrophenol, acting as the material, reacted in five steps to give BAPTA-derived chelators. The Ca²⁺ affinity of BAPTA chelators could increase significantly by addition of electron-donating groups and decrease by electron-withdrawing groups. Compounds 3a–e were treated with iron powder instead of hydrogenation, obtaining a satisfying yield. The structures of all compounds were characterized by infrared, ¹H NMR, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) spectra.

Keywords:

• BAPTA
• chelator
• ion indicator
• synthesis

ACKNOWLEDGMENTS

This work was supported by the National Natural Science Foundation of China (20872117), the Ph.D. Program Foundation of Chinese University (20050697003), and the Science and Technology Program Foundation of Xi' an City (YF07070).