Efficient Reduction of tetrakis(2‐Cyanoethyl)cyclen with Sodium–Toluene and Synthesis of Carboxymethyl‐ and Hydroxyethyl Functionalized Second Generation Pendant Arms Appended Cyclens

Abstract

1,4,7,10‐tetrakis(2‐Cyanoethyl)‐1,4,7,10‐tetraazacyclododecane (1) is efficiently reduced with sodium–toluene to give 1,4,7,10‐tetrakis(3‐aminopropyl)‐1,4,7,10‐tetraazacyclododecane (2), which on alkylation affords carboxymethyl‐ and hydroxyethyl‐functionalized second generation pendant arm appended cyclens, 1,4,7,10‐tetrakis[N,N‐bis(carboxymethyl)‐3‐propylamino]‐1,4,7,10‐tetraazacyclododecane (3), and 1,4,7,10‐tetrakis[N,N‐bis(2‐hydroxyethyl)‐3‐propylamino]‐1,4,7,10‐tetraazacyclododecane (4).

Keywords:

• Functionalized cyclen
• Sodium‐toluene reduction
• Octacarboxy functionalized cyclen
• Octahydroxy functionalized cyclen

Acknowledgments

This research was carried out with the financial support from a funding agency of the Government of India. We are grateful to Dr. D. Suresh Kumar, Department of Chemistry Loyola College, Chennai and Dr. M. S. Moni, RSIC, Indian Institute of Technology, Chennai, for useful discussion with spectral data and HPLC.