The introduction of alkoxy in 4-substituted quinazolines
enhanced both enzyme inhibitions significantly, especially the introduction of methoxy side chains in the interposition(Compare 5c).
The majority of [alpha]-adrenoreceptor antagonists displays a competitive mechanism of action and belongs to a variety of different structural classes such as yohimbanes, ergot alkaloids, quinazolines
, N-arylpiperazines, imidazolines, phenylalkylamines, benzodioxanes, indoles, 1,4-dihydropyridines, hetero-fused 3-benzazepines and dibenzoquinolizines [17-19].
Oxazines  and quinazolines
 are natural products which exhibit a widespread spectrum of biological activity including antitumor [16-18], anti-inflammatory , and antiplatelet  properties.
Cho et al., "Virtual screening and synthesis of quinazolines
as novel JAK2 inhibitors," Bioorganic and Medicinal Chemistry, vol.
: an illustrated review," Journal of Advanced Pharmacy Education & Research, vol.
and quinazolinones are classes of fused heterocycles that are of considerable interest because of the diverse range of their biological properties .
Among nitrogen-containing heterocyclic molecules, substituted quinazolinones and quinazolines
are considered as important therapeutic scaffolds .
Indazole derivatives are reported to exhibit antibacterial [1,2], antifungal [1.2], antiproliferative , antigiogenic , antiarrhythmic and analgesic  activities and antihypertensive properties , while quinazolines
exhibit antitumor , antimicrobial  antitubercular , antiagonists , anticonvulsant  and analgesic activities.
Chemically the members of the genus Sida contain [beta]-phenethylamines ([beta]-phenethylamine, ephedrine and [phi] ephedrine), quinazolines
(vasicine, vasicinol and vasicinone) and carboxylated tryptamines in addition to choline and betaine .
The book contains six chapters covering synthesis, reactions and applications in the following subject areas: pyridazines, cinnolines, benzocinnolines and phthalazines; pyrimidines and quinazolines
; pyrazines and related ring structures; phenzine, oxazine, thiazine and sulphur dyes; quinazoline
alkaloids; six-membered rings with three or more hetero-atoms.
Shahar Yar, "Synthesis and antihypertensive screening of new derivatives of quinazolines
linked with isoxazole," BioMed Research International, vol.
Revisited: Search for Novel Anxiolytic and GABAergic Agents, Bioorg.