Synthesis of C-14-labeled novel IKK inhibitor:: 2-[14C]-N-(6-chloro-9H-pyrido [3,4-b]indol-8-yl)-3-pyridinecarboxamide

2-[C-14]-N-(6-Chloro-9H-pyrido [3,4-b]indol-8-yl)-3-pyridinecarboxamide (9A, also referred to as [C-14]-PS-1145) was synthesized from [C-14]-paraformaldehyde in five steps in an overall radiochemical yield of 15%. The key intermediate 1-[C-14]-6-chloro-1,2,3,4-tetrahydro-beta-carboline was obtained by Pictet-Spengler cyclization of chlorotryptamine with [C-14]-paraformaldehyde. Similar reactions were conducted with tryptamine to address the generality of the methodology. Copyright (c) 2005 John Wiley & Sons, Ltd.