1,1'-Carbonyldiimidazole → HCID 59708795, compound

Participants

Reaction Steps

1,1′-Carbonyldiimidazole (129 mg, 0.796 mmol) was added to a solution of 5-[4-(4-tert-butoxycarbonylaminobutyl)piperazin-1-yl]pentanoic acid (111) (219 mg, 0.613 mmol) in anhydrous dichloromethane (8 mL) and the mixture was stirred at room temperature for 2 hours. N-Boc piperazine (148 mg, 0.796 mmol) was then added in one portion and the reaction mixture was stirred at room temperature for an additional 16 hours. The mixture was then concentrated under reduced pressure, and the resulting residue was purified by Biotage silica gel column chromatography using methanol/dichloromethane (gradient 0% to 2%) to give 4-{5-[4-(4-tert-butoxycarbonylaminobutyl)piperazin-1-yl]pentanoyl}piperazine-1-carboxylic acid tert-butyl ester 112 as a viscous, yellow oil (309 mg, 96%): 1H NMR (500 MHz, CDCl3) δ 1.44 (s, 9H), 1.48 (s, 9H), 1.55 (m, 6H), 1.66 (m, 2H), 2.35 (m, 8H), 2.48 (m, 6H), 3.11 (m, 2H), 3.40 (m, 2H), 3.44 (m, 4H), 3.58 (m, 2H), 5.30 (br, 1H). m/z (ESI) 526 [C27H51N5O5+H]+.

Provenance & Evidence