1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → Ethyl 3-[6-(5-{5-chloro-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-1H-indol-3-yl]propanoate

Participants

Reaction Steps

EDCI (356 mg) and HOBT (306 mg) were added to a solution of 5-chloro-6-[(1-methylethyl)oxy]-3-pyridinecarboxylic acid (200 mg) in THF (5 mL) at RT. The resulting solution was stirred for 30 mins. Ethyl 3-{6-[(Z)-(hydroxyamino)(imino)methyl]-1H-indol-3-yl}propanoate (D107) (383 mg) in THF (5 mL) was added and the reaction mixture was stirred at RT for 2 hours. TBAF (970 mg) was then added. The reaction vessel was sealed and heated in Biotage Initiator using initial normal to 120° C. for 90 mins. After cooling, the reaction was quenched with water, and extracted with EtOAc for 3 times. The combined organic solution was washed with brine, dried over anhydrous sodium sulfate. The dried solution was concentrated. The residue was purified by column chromatography (20% EtOAc in hexane) to afford ethyl 3-[6-(5-{5-chloro-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-1H-indol-3-yl]propanoate (D108) (310 mg) as a pale yellow solid. δH (CDCl3, 400 MHz): 1.25 (3H, t), 1.46 (6H, d), 2.74 (2H, t), 3.15 (2H, t), 4.15 (2H, q), 5.51 (1H, m), 7.17 (1H, d), 7.72 (1H, d), 7.93 (1H, dd), 8.20 (2H, d), 8.42 (1H, d), 8.89 (1H, d). MS (ES): C23H23ClN4O4 requires 454; found 455.2 (M+H+).

Provenance & Evidence