Syntheses of H-3-labeled, C-14-labeled, and H-2(4)-labeled SCH 444877, phosphodiesterase type 5 inhibitors

The syntheses of [H-3]SCH 444877, [H-2(4)]SCH 444877, and [C-14]SCH 444877 are described. [H-3]SCH 444877 was prepared in three steps from tritium gas. [H-2(4)]SCH 444877 was synthesized from [H-2(4)]ethanolamine in four steps with an overall yield of 40%. [C-14]SCH 444877 was prepared from barium [C-14]cyanamide in 10 steps with an overall yield of 8.1%.Copyright (c) 2013 John Wiley & Sons, Ltd.