Tyrosine Kinase Inhibitors. 15. 4-(Phenylamino)quinazoline and 4-(Phenylamino)pyrido[d]pyrimidine Acrylamides as Irreversible Inhibitors of the ATP Binding Site of the Epidermal Growth Factor Receptor

Abstract

A series of 6- and 7-acrylamide derivatives of the 4-(phenylamino)quinazoline and -pyridopyrimidine classes of epidermal growth factor receptor (EGFR) inhibitors were prepared from the corresponding amino compounds by reaction with either acryloyl chloride/base or acrylic acid/1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. All of the 6-acrylamides, but only the parent quinazoline 7-acrylamide, were irreversible inhibitors of the isolated enzyme, confirming that the former are better-positioned, when bound to the enzyme, to react with the critical cysteine-773. Quinazoline, pyrido[3,4-d]pyrimidine, and pyrido[3,2-d]pyrimidine 6-acrylamides were all irreversible inhibitors and showed similar high potencies in the enzyme assay (likely due to titration of the available enzyme). However the pyrido[3,2-d]pyrimidine analogues were 2-6-fold less potent than the others in a cellular autophosphorylation assay for EGFR in A431 cells. The quinazolines were generally less potent overall toward inhibition of heregulin-stimulated autophosphorylation of erbB2 (in MDA-MB-453-cells), whereas the pyridopyrimidines were equipotent. Selected compounds were evaluated in A431 epidermoid and H125 non-small-cell lung cancer human tumor xenografts. The compounds showed better activity when given orally than intraperitoneally. All showed significant tumor growth inhibition (stasis) over a dose range. The poor aqueous solubility of the compounds was a drawback, requiring formulation as fine particulate emulsions.

The EGF receptor family as targets for cancer therapy

“…Coadministration of ZD1839 was found to enhance the growth-inhibitory e ects of all cytotoxic drugs tested. These results provide evidence con®rming the earlier studies with MAbs, which showed that interfering with (Smaill et al, 1999) 7 intact cells 9 intact cells PD153035 29 2300 NO Preclinical (Fry et al, 1994) PD 168393 0.70 Not reported YES Preclinical studies (Fry et al, 1998) 4 EGFr signaling is a valid approach to improve the e cacy of chemotherapy.…”

“…PD168393 is a prototype of these compounds, and comparison with an equally potent but reversible analogue showed that the irreversible inhibitor has stronger in vivo antitumor activity against A431 xenografts (Fry et al, 1998). CI-1033, a compound that similarly inhibits both the EGFr and erbB2 in an irreversible fashion, has demonstrated potent antitumor activity in xenografts models expressing both the EGFr and erbB2, and is currently being evaluated in phase I studies (Smaill et al, 1999). These agents, which inhibit two receptors of the same family of receptors, are known as`pan-HER' inhibitors.…”

Irreversible Inhibition of Epidermal Growth Factor Receptor Activity by 3-Aminopropanamides

“…In principle, the long-lasting effect observed on EGFR autophosphorylation could be ascribed to different phenomena: (i) accumulation of the inhibitor in cells, as previously demonstrated for some reversible quinazolines; 66 (ii) conversion of the competitive inhibitor into an irreversible one at the active site of the enzyme (mechanism-based inhibition), as described for other β-aminocarbonyl compounds; 38 (iii) generation of the corresponding reactive acrylamide, as described for aryl β-aminoethyl ketones that have potential application as prodrugs of unsaturated ketones. 67 As previously described, 54,66 some reversible quinazoline EGFR inhibitors are sequestered in cells generating falsepositive results in the autophosphorylation assay based on the 8 h washout protocol. As an example, the fully reversible compound 1, which is strongly sequestered in cells, produced 46.4% ± 6.7% inhibition of EGFR autophosphorylation (A459 cells) at 1 μM concentration 8 h after removal from the medium.…”

Microwave-Assisted Synthesis of Bioactive Six-Membered Heterocycles and Their Fused Analogues

“…Its derivatives have been designed and synthesized as therapeutic agents [21][22][23][24], as herbicides, fungicides, pesticides and as fluorescent dyes [25,26]. They have been commonly used as scaffolds for natural product synthesis (e.g., NAD nucleotides, pyridoxol (vitamin B6), and pyridine alkaloids) [27][28][29].…”