Quinazoline is a compound made up of two fused six-membered simple aromatic ring

Simple aromatic ring

Simple aromatic rings, also known as simple arenes or simple aromatics, are aromatic organic compounds that consist only of a conjugated planar ring system with delocalized pi electron clouds. Many simple aromatic rings have trivial names. They are usually found as substructures of more complex...

s, a benzene

Benzene

Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 ring and a pyrimidine

Pyrimidine

Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring...

 ring. Its chemical formula is C₈H₆N₂. Quinazoline is yellow and crystalline. Any derivative of quinazoline may be described as a quinazoline compound.

Medicinally it has been used in various areas especially as an anti-malarial agent and in cancer treatment.
One example of a compound containing the quinazoline structure is doxazosin mesylate.

It is isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

ic with quinoxaline

Quinoxaline

A quinoxaline, also called a benzopyrazine, in organic chemistry, is a heterocyclic compound containing a ring complex made up of a benzene ring and a pyrazine ring...

, phthalazine and cinnoline

Cinnoline

Cinnoline is an aromatic heterocyclic compound with the formula C8H6N2. It is isomeric with quinoxaline, phthalazine and quinazoline.-Properties:...

.