A mixture of 1,4,7,10,13-penta(p-toluenesulfonyl)-1,4,7,10,13-pentaazacyclopentadecane prepared as in Example 1D (168 g, 0.170 mole) and concentrated H2SO4 (500 ml) was heated at 100° C. with stirring under a dry argon atmosphere for 70 h. To the resulting dark brown solution ethanol (500 ml) was added dropwise with stirring at 0° C. followed by ethyl ether (3 l). The white solid was filtered and washed with ethyl ether. The solid was then dissolved in H2O (500 ml) and the resulting solution washed with ethyl ether. Upon reducing the volume of the solution in vacuo to 200 ml, the pH was adjusted to 10-11 with 10N NaOH and the solvent was removed in vacuo. Ethanol (500 ml) was then added and removed in vacuo to dryness. The resulting tan oily solid was extracted with hot THF (2×500 ml) and filtered at room temperature. The filtrates were combined and the solvent removed in vacuo to give the crude product as a yellow crystalline solid which was then redissolved in CH3CN and filtered to remove insoluble impurities. Recrystallization from cold (-20° C.) CH3CN gave 11.3 g (31% yield) of the product as colorless needles: mp 108°-9° C.; 1H NMR (CDCl3) δ 1.74 (br s, 5 H), 2.73 (s, 20 H); Exact mass (M+Li)+ : calcd, 222.2270; Found, 222.2269 (C10H25N5Li).
