In organic chemistry, atoms other than carbon and hydrogen are generally referred to as heteroatoms. The most common heteroatoms are nitrogen, oxygen and sulfur. Now I present to you an article called Synthesis of new derivatives of [1,2,5]triazepino[1,2-a]cinnoline. I. Synthesis of 4-oxo-1,2,3,4-tetrahydrocinnoline hydrochlorides, published in 1989, which mentions a compound: 137195-33-6, mainly applied to oxotetrahydrocinnoline hydrochloride; cinnoline oxotetrahydro, Formula: C8H9ClN2O.
The title cinnolines (I, R1 = R3 = R4 = H, R2 = H, Cl, Me; R1 = R2 = R3 = H, R4 = Cl, Me, OMe; R1 = R4 = H, R2 = R3 = OMe; R2 = R3 = R4 = H, R1 = Cl) were prepared by reduction of appropriately substituted 4-hydroxycinnlines (70-80% yields) and 4-hydroxy-3-cinnolinecarboxylic acids (55-67% yields) with Zn dust in AcOH-EtOH.
Compounds in my other articles are similar to this one(2,3-Dihydrocinnolin-4(1H)-one hydrochloride)Formula: C8H9ClN2O, you can compare them to see their pros and cons in some ways,such as convenient, effective and so on.
Reference:
Cinnoline – Wikipedia,
Cinnoline – an overview | ScienceDirect Topics