摘要 |
<p>A directly synthetic method for preparing tris-alkylated 1,4,7,10-tetraazacyclododecanes by the reactions of 1,4,7,10-tetraazacyclododecane (cyclen) and appropriate electrophiles is accomplished in high yield. The method provides operational convenience, starting material availability, cost economy, atom efficiency and reaction insensitivity to temperature, moisture, and concentrations of starting materials. With this method, the yield of tris-(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane can be 77%, the highest reported. The yield of other tris-N alkylated products can be in the range of 65-84%.</p> |