Diisopropylethylamine → 15-{(3,5-Bis-tert-butoxycarbonylmethoxybenzyl)-[2-(2,5-dioxo-pyrrolidin-1-yloxycarbonyl)ethyl]carbamoyl}pentadecanoic acid 4-methoxy-benzyl ester

Participants

Reaction Conditions

Reaction Steps

15-[(3,5-Bis-tert-butoxycarbonylmethoxybenzyl)-(2-carboxyethyl)carbamoyl]pentadecanoic acid 4-methoxybenzyl ester (190 mg, 0.23 mmol) was dissolved in THF (5 mL). The mixture was cooled with an ice bath. Diisopropylethylamin (0.047 mL, 0.28 mmol) and O—(N-succinimidyl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (83 mg, 0.28 mmol) was added. The mixture was stirred under nitrogen at 0° C. After 30 minutes the ice cooling was removed and the mixture was stirred for an additional 3 hours. Solvent removed in vacuo. The crude product was dissolved in ethyl acetate (50 mL), washed with aqueous phosphate buffer (pH=5.5) (3×25 mL). The organic phase was dried (Na2SO4), solvent removed in vacuo to yield the title compound (163 mg) which was used in subsequent step.

Provenance & Evidence