A simple and efficient method has been reported by following a close pH control between 2 and 3 during slow addition of benzyl chloroformate to give the symmetrically 1,7-diprotected 1,4,7,10-tetraaza- cyclododecane (cyclen) derivative 1,7-bis(benzyloxycarbonyl)-cyclen (4). The benzyloxycarbonyl derivative 4 reacted with 1-[4-(2-bromoethoxy)phenoxy]methyl benzene (2) by one-pot reaction in the presence of diisopropylethylamine to aftord intermediates 1,7-bis[2-(4-benzyloxyphenoxy)ethyl]-4,10-bis(benzyloxy- phenoxy)-1,4,7,10-tetraazacyclododencane (5) and 4-[2-(4-benzyloxyphenoxy)ethyl]-1,7-bis(benzyloxy- car-bonyl)-1,4,7,10-tetraazacyclododecane (6). Catalytic hydrogenation of 5 and 6 in ethanol cleaved the benzyloxycarbonyl and benzyl groups to give two novel pendant-armed phe-nol-containing cyclen derivatives 1,7-bis[2-(4-hydroxyphenoxy)ethyl]-1,4,7,10-tetraazacyclododecane (7) and 1-[2-(4-hydroxyphenoxy)- ethyl]-1,4,7,10-tetraazacyclododecane (8) in high yields. The structures of the new macrocyclic compounds were characterized by ¹H NMR, IR and MS spectra. The crystal structure of compound 7 was determined by X-ray single crystal diffraction method, which belongs to a monoclinic system with space group C2/c, a＝2.4145(6) nm, b＝1.6012(4) nm, c＝1.6632(4) nm, α＝γ＝90°, β＝120.360(3)°, V＝5.5486(6) nm³, Z＝8, D_c＝1.146 g/cm³, F(000)＝2056, μ＝0.082 mm^－1, R＝0.0853, and wR＝0.2331 [I＞2σ (I)].

Key words: benzyl chloroformate, crystal structure, 1,4,7,10-tetraazacyclododecane