title: Tyrosine kinase inhibitors. 9. Synthesis and evaluation of fused tricyclic quinazoline analogues as ATP site inhibitors of the tyrosine kinase activity of the epidermal growth factor receptor.
abstract: Following the discovery of 4-[(3-bromophenyl)amino]-6,7-dimethoxyquinazoline (4; PD 153035) as an extremely potent (IC(50) 0.025 nM) inhibitor of the tyrosine kinase activity of the epidermal growth factor receptor (EGFR), several fused tricyclic quinazoline analogues have been prepared and evaluated for their ability to inhibit the enzyme. The most potent compound was the linear imidazo[4,5-g]quinazoline (8), which exhibited an IC(50) of 0.008 nM for inhibition of phosphorylation of a fragment of phospholipase C-gamma-1 as substrate. While N-methyl analogues of 8 showed similar potency, analogous N-[2-(dimethylamino)ethyl] derivatives were less effective. The next most potent compounds were the linear pyrazoloquinazolines (19 and 20) (IC(50)s 0.34 and 0.44 nM) and pyrroloquinazoline (21) (IC(50) 0.44nM), while several other linear tricyclic ring systems of similar geometry to 8 (triazolo-, thiazolo-, and pyrazinoquinazolines) were less effective. In the imidazo[4,5-g]quinazoline and pyrroloquinazoline series, the corresponding angular isomers were also much less effective than the linear ones. These results are consistent with structure-activity relationship studies previously developed for the 4-[(3-bromophenyl)amino] quinazolines, which suggested that small electron-donating substituents at the 6- and 7-positions were desirable for high potency. Cellular studies of the linear imidazoloquinazoline 8 show that it can enter cells and rapidly and very selectively shut down EGF-stimulated signal transmission by binding competitively at the ATP site of the EGFR.
authors.affiliation: Cancer Research Laboratory, University of Auckland School of Medicine, New Zealand.
authors.forename: G W
authors.initials: GW
authors.lastname: Rewcastle
authors.forename: B D
authors.initials: BD
authors.lastname: Palmer
authors.forename: A J
authors.initials: AJ
authors.lastname: Bridges
authors.forename: H D
authors.initials: HD
authors.lastname: Showalter
authors.forename: L
authors.initials: L
authors.lastname: Sun
authors.forename: J
authors.initials: J
authors.lastname: Nelson
authors.forename: A
authors.initials: A
authors.lastname: McMichael
authors.forename: A J
authors.initials: AJ
authors.lastname: Kraker
authors.forename: D W
authors.initials: DW
authors.lastname: Fry
authors.forename: W A
authors.initials: WA
authors.lastname: Denny
mesh_terms: D016475:3T3 Cells; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002294:Carcinoma, Squamous Cell; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008938:Mitosis / Q000187:drug effects; D015394:Molecular Structure; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D011799:Quinazolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013936:Thymidine / Q000378:metabolism
chemical_list: C512698:8-((3-bromophenyl)amino)-3-methyl-3H-imidazo(4,5-g)quinazoline; D004791:Enzyme Inhibitors; D006133:Growth Substances; D006571:Heterocyclic Compounds; D007093:Imidazoles; D007202:Indicators and Reagents; D010982:Platelet-Derived Growth Factor; D011799:Quinazolines; D016222:Fibroblast Growth Factor 2; D004815:Epidermal Growth Factor; D000255:Adenosine Triphosphate; D004247:DNA; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D013936:Thymidine