1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → 1-[3-(3,4-Dihydro-5-hydroxy-2,2,4-trimethyl-7-pentyl-2H-1-benzopyran-3-yl)-1-oxopropoxy]-2,5-pyrrolidinedione

Participants

Reaction Steps

To a solution of 297 mg (0.88 mmol) of 3,4-Dihydro-5-hydroxy-2,2,4-trimethyl-7-pentyl-2H-1-benzopyran-3-propanoic acid in 20 mL of anhy. CH2Cl2 under argon was added 246 mg (2.14 mmol) of N-hydroxysuccinimide (Aldrich) and the reaction stirred for 15 min. 408 mg (2.14 mmol) of 1-ethyl-3-(dimethylaminopropyl)carbodiimide (Sigma) was then added and the reaction stirred at RT for 3 hr. The reaction was diluted to five times the volume with CH2Cl2, washed with 0.1N aq. HCl that had been saturated with NaCl, followed by sat. aq. NaCl, followed by sat. aq. NaHCO3 (×3), dried and evaporated under reduced pressure. The residue was purified by flash chromatography on silica gel, eluting with 1:1 EtOAc-CH2Cl2. The product fractions were combined and evaporated under reduced pressure and dried under high vacuum to give 297 mg (78%) of 1-[3-(3,4-Dihydro-5-hydroxy-2,2,4-trimethyl-7-pentyl-2H-1-benzopyran-3-yl)-1-oxopropoxy]-2,5-pyrrolidinedione as a white foam. HR (+) FAB MS: Calc (M+H), 432.2386; Observed, 432.2413.

Provenance & Evidence