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

Participants

Reaction Steps

EDCI (385 mg) and HOBT (332 mg) were added to a solution of 6-[(1-methylethyl)oxy]-5-(trifluoromethyl)-3-pyridinecarboxylic acid (250 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) (413 mg) in THF (5 mL) was added and the reaction mixture was stirred at RT for 2 hours. TBAF (1.1 g) 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 EA 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-[6-[(1-methylethyl)oxy]-5-(trifluoromethyl)-3-pyridinyl]-1,2,4-oxadiazol-3-yl}-1H-indol-3-yl)propanoate (D109) (310 mg) as a pale yellow solid. δH (CDCl3, 400 MHz): 1.25 (3H, t), 1.45 (6H, d), 2.74 (2H, t), 3.15 (2H, t), 4.16 (2H, q), 5.60 (1H, m), 7.17 (1H, t), 7.73 (1H, d), 7.94 (1H, dd), 8.21 (2H, dd), 8.64 (1H, t), 9.14 (1H, d). δF (CDCl3, 376 MHz): −64.3. MS (ES): C24H23F3N4O4 requires 488; found 489.2 (M+H+).

Provenance & Evidence