What does the prefix "dihydro" in the systematic name of luminol refer to? I'm doing a research project on the fascinating chemiluminescent molecule luminol, and figured it would be a good idea to start breaking down the systematic name of the chemical and linking the terms to the structure. The systematic name of luminol is 5-amino-2,3-dihydrophthalazine-1,4-dione, and I get it all apart from the "dihydro" - any help? Thank you very much in advance! :)
On the left is 5-amino-2,3-dihydrophthalazine-1,4-dione and on the right is the molecule which the name is based on, phthalazine. The 2,3-dihydro refers to the fact that at the 2 and 3 positions (the two nitrogens) hydrogens have been added (hydro is the prefix for hydrogen).