1,1'-Carbonyldiimidazole → tert-Butyl 4-[2-({4-chloro-2-[2-(dimethylamino)-2-oxoethoxy]benzoyl}amino)ethyl]-1-piperazinecarboxylate

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Reaction Steps

The product from step (b) (0.7 g) and 1,1′-carbonyldiimidazole (0.62 g) were dissolved in N,N-dimethylformamide (10 ml) and stirred at room temperature for 1 hour. tert-Butyl 4-(2-aminoethyl)-1-piperazinecarboxylate (2.73 g) was added, the solution stirred for 16 hours and then evaporated to leave a gum. Dichloromethane and sodium bicarbonate solution were added, the organic phase was separated, dried and concentrated to a gum which was purified by chromatography (ethyl acetate:triethylamine, 10:1) to give the product as a solid (0.62 g), m.p. 139-140° C.

Provenance & Evidence