Figure - PMC

Skip to main content

View full-text article in PMC

. Author manuscript; available in PMC: 2008 Aug 14.

Published in final edited form as: J Am Chem Soc. 2006 Jun 14;128(23):7463–7465. doi: 10.1021/ja0618954

Scheme 4 — Reagents. (a) 1. K₂CO₃. 2. HF·Py, Py, 74% over 2 steps. 2. TsCl. 3. K₂CO₃, 78% over 2 steps. (b) N-Boc-L-Cys(SH)-OCHPh₂ (an inseparable mixture of 16 and 17), 85%. (c) 1. Pd(PPh₃)₄, AcOH, 72%. 2. 1,3,5-(i-Pr)₃C₆H₂CO₂H/Et₃N salt, 80 °C, xylene. 3. TFA, CH₂Cl₂, followed by HPLC separation of 18 and 19.