Diethyl Ether → 2,2'-(1,4,8,11-Tetraazacyclotetradecane-1,8-diyl)diacetic acid

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Reaction Steps

Compound (5) (1.12 g, 2.61 mmol) was dissolved in a mixture of CF3CO2H (TFA) and CH2Cl2 (1:1 (v/v), 40 ml). The resultant mixture was stirred at an ambient temperature for 24 hours. The solvent was evaporated under reduced pressure to give an oily residue, which was then treated with Et2O to obtain an off-white solid of compound (6) (1.39 g, 98% yield, calculated as 2 equivalents of TFA for the basic weight). 1H NMR (500 MHz, D2O): δ 3.31 (brs, 2H), 3.22-2.95 (m, 8H), 2.94-2.72 (m, 8H), 2.64 (brs, 2H), 1.83 (brs, 4H); 13C NMR (125 MHz, D2O): δ 180.9, 57.5, 56.9, 55.4, 49.2, 46.2, 23.7; HRMS (FAB) calculated for C14H28N4O4: 317.2189 [(M+H)+], measured value: 317.2185 [(M+H)+].

Provenance & Evidence