A new synthesis of cyclen (1,4,7,10-tetraazacyclododecane)

Weisman, G. R., & Reed, D. P. (1996). A new synthesis of cyclen (1,4,7,10-tetraazacyclododecane). Journal of Organic Chemistry, 61(15), 5186–5187. https://doi.org/10.1021/jo9606665