Complex sentence: DC editor Carmine Infantino had tried to acquire the license to publish "Planet of the Apes" comic books but when this failed to happen he asked Jack Kirby for a series with a similar concept.
Split into simpler sentences: DC editor Carmine Infantino had tried to acquire the license to publish "Planet of the Apes" comic books. When this failed to happen, he asked Jack Kirby for a series with a similar concept.