In an alternate synthesis, 1-ethyluracil is first reacted with phosphorus pentasulfide and then the introduced sulfur is then displaced with ammonia to form (4).
1-ethyluracil is first reacted with phosphorus pentasulfide is then displaced with ammonia. This was in an alternate synthesis. This was to form (4). Then the introduced sulfur is then displaced with ammonia. This was in an alternate synthesis. This was to form (4).