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

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