Preparation of Functionalized, Conformationally Constrained DTPA Analogues from <scp>l</scp>- or <scp>d</scp>-Serine and <i>trans</i>-4-Hydroxy-<scp>l</scp>-proline. Hydroxymethyl Substituents on the Central Acetic Acid and on the Backbone
作者:I. Fraser Pickersgill、Henry Rapoport
DOI:10.1021/jo000071g
日期:2000.6.1
acetic acid or on the backbone are described. Key synthetic steps include (i) displacement of the 4-hydroxyl group of N-BOC-trans-4-hydroxy-L-proline benzyl ester, via activation as the triflate, with suitable amines derived from L- or D-serine, (ii) the low-temperature alkylation of diethylenetriamines with the triflate of benzyl glycolate, thereby minimizing competitive lactamization, to give DTPA pentabenzyl