Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Synthesis of intermediates a4, a7–a11, a13–a14 and a16–a21. Reagents and conditions: (a) 3-aminopiperidine-2,6-dione, NaOAc, AcOH, 140 °C, 58.3–68.7% yield; (b) DIPEA, DMF, 90 °C,53.6–65.2% yield; (c) CF3COOH, CH2Cl2, 25 °C, 86.3–90.2% yield; (d) HATU, DIPEA, 25 °C, 67.4–75.3% yield; (e) TsCl, Et3N, CH2Cl2, 30 °C, 72.6–79.3% yield; (f) corresponding bromocarboxylic acid, SOCl2, CH2Cl2, 40 °C, 61.5–85.8% yield.
