Scheme 1.

The synthesis of indoline and aniline analogs.^a

^aReagents and conditions: (a) triphosgene, aq. NaHCO₃, CH₂Cl₂, 25 °C, 1 h; (b) NH₂(CH₂)₄CO₂Et, DIPEA, CH₂Cl₂, 25 °C, 1 h, 53% for 2 steps; (c) 1 N NaOH, THF/MeOH (2/1), 25 °C, 30 min, 73%; (d) ClCO₂Et, Et₃N, THF, 25 °C, 1.5 h; NH₂OTBS, MeOH, 25 °C, 1 h, 88%; (e) TFA, CH₂Cl₂, 25 °C, 25 min, 78%; (f) ClCOCH₂(CH₂)₄CO₂Et, Et₃N, CH₂Cl₂, 25 °C, 20 min, 67%; (g) 1 N LiOH, THF/MeOH (2/1), 25 °C, 1.5 h, 99%; (h) ClCO₂Et, Et₃N, THF, 25 °C, 1 h; NH₂OTBS, MeOH, 25 °C, 1 h; (i) TFA, CH₂Cl₂, 25 °C, 25 min, 21% for 2 steps; (j) OCN(CH₂)₅CO₂Et, CH₂Cl₂/MeCN (1/1), 25 °C, 18 h, 35%; (k) 1 N NaOH, THF/MeOH (2/1), 25 °C, 3 h, 93%; (l) ClCO₂Et, Et₃N, THF, 25 °C, 1 h; NH₂OTBS, MeOH, 25 °C, 1 h, 94%; (m) TFA, CH₂Cl₂, 25 °C, 25 min, 81%.