Dicyclohexylcarbodiimide → methyl N-(tert-butoxycarbonyl)-4-({N-[6-(2,5-dioxo-2,5-dihydro-1H pyrrol-1-yl)hexanoyl]glycyl}amino)-L-phenylalaninate

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 4-amino-N-(tert-butoxycarbonyl)-L-phenylalaninate (4.1 g, 15.3 mmol, 1 eq.) in dry N,N-dimethylformamide (70 mL) was added N,N′-Dicyclohexylcarbodiimide (2.9 g, 15.3 mmol, 1 eq.) at 0° C. The mixture was stirred at 0° C. for 30 minutes. A solution of 2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)acetic acid (3 g, 10.2 mmol, 0.66 eq.) in dry N,N-dimethylformamide (20 mL) was added at 0° C. The mixture was stirred at room temperature for 3 days. The mixture was filtered. The filtrate was poured into ice water (200 mL) and extracted with EtOAc (200 mL×3). The extract was washed with brine (200 mL), dried over Na2SO4 and concentrated in vacuo to afford #251 (1.8 g, 32.3% yield) as a light yellow solid. HPLC (Protocol Q2) [M+Na+] 567.3, retention time=1.02 min

Provenance & Evidence