1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → Ethyl 3-(7-{5-[3,4-bis(ethyloxy)phenyl]-1,2,4-oxadiazol-3-yl}-1H-indol-3-yl)propanoate

Participants

Reaction Steps

To a solution of 3,4-bis(ethyloxy)benzoic acid (631 mg) in tetrahydrofuran (15 mL) stirred at room temperature was added EDCI (767 mg) and HOBT (613 mg). The reaction mixture was stirred for 2 h. Then ethyl 3-{7-[(Z)-(hydroxyamino)(imino)methyl]-1H-indol-3-yl}propanoate (D35) (551 mg) was added. The reaction mixture was stirred at 60° C. for 2 h, and then TBAF (2092 mg) was added. The reaction vessel was sealed and heated in Biotage Initiator using initial normal to 130° C. for 3 h. After cooling the reaction, the solvent was removed. Water (90 mL) and ethanol (30 mL) was added to the residue, a yellow solid was formed, filtered and dried in vacuo to afford the product ethyl 3-(7-{5-[3,4-bis(ethyloxy)phenyl]-1,2,4-oxadiazol-3-yl}-1H-indol-3-yl)propanoate (D66) (706 mg). δH (CDCl3, 400 MHz): 1.26 (3H, t), 1.52-1.57 (6H, m), 2.76 (2H, t), 3.18 (2H, t), 4.16 (2H, q), 4.19-4.28 (4H, m), 7.02 (1H, d), 7.20 (1H, d), 7.28 (1H, t), 7.74 (1H, d), 7.81 (1H, d), 7.86 (1H, dd), 8.14 (1H, dd), 9.64 (1H, s). MS (ES): C25H27N3O5 requires 449. found 450.2 (M+H+).

Provenance & Evidence