I'll make this as brief as possible. Around 1960, an animation producer named Sam Singer produced a series of cartoons called Sinbad Jr, featuring a young adventurer with a magic belt and a pet parrot. Rather quickly, Mr. Singer ran into two problems that prevented the distribution of these cartoons. One was that they weren't very good. The other was that the motion picture company American-International informed him, presumably via their attorneys, that they'd released a movie called The Magic Voyage of Sinbad and they owned the name.
I'm not sure how compelling their claim was but it held up the release of the films for several years…until '65 when a compromise of sorts was brokered, one which reportedly did not make Singer very happy. American-International wound up distributing his cartoons but they also funded another series of Sinbad Jr cartoons, which were produced by Hanna-Barbera. The idea apparently was to make a better show and to lose the Singer-produced cartoons amongst the new version. I remember my puzzlement in '65 when the cartoons turned up on local TV — same premise, same characters, different theme, different voices, etc. (The voice of Sinbad on the Singer version was Dallas McKinnon. On the H-B version, Sinbad's voice came from Tim Matheson, aka Tim Matthieson, and Mel Blanc was the parrot.)
What we have here today are the two openings. The first is from the Sam Singer version…
And now, here's the opening of the episodes done by Hanna-Barbera. When I was a kid, I thought this was just about the jazziest theme song ever on a cartoon show. It's still pretty good.