1,4,7,10-Tetraazacyclododecane → Tri-tert-butyl 1,4,7,10-Tetraazacyclododecane-1,4,7-triacetate

Participants

Reaction Steps

Sodium acetate (25.298 g: 0.3084 mol) was added to a stirred suspension of 1,4,7,10-tetraazacyclododecane (17.71 g; 0.1028 mol) in N,N'-dimethylacetamide (DMA) (312 mL) at ambient temperature. A solution of bromoacetic acid t-butyl ester (49.8 mL; 0.3084 mol) in DMA (160 mL) was added dropwise to the stirred mixture, and the mixture stirred at ambient temperature for 11 days. A solid precipitate was isolated by suction filtration and washed once with cold DMA (20 mL). Residual DMA was removed by heating the solid at 45° C. under reduced pressure for 20 hrs. The white solid (40.18 g) was dissolved in chloroform (200 mL) and washed with deionized water (3×300 mL). The organic layer was dried over MgSO4 and subsequently concentrated to a solid which was further dried under reduced pressure to yield the title compound as a white powder, 36.3 g (69%).

Provenance & Evidence