Pteroic acid. Most people know folic acid as vitamin B9. Chemically, however, folic acid can be imagined as three molecular pieces joined together: A pteridine system. p-Aminobenzoic acid. And glutamic acid.
The first two together make pteroic acid. Add glutamic acid, and you have folic acid. So pteroic acid is a little like seeing the chassis underneath a finished car. And chemists can actually run this process backward.
Global Chemical Database