title: Design, synthesis and biological evaluation of substituted pyrrolo[2,3-d]pyrimidines as multiple receptor tyrosine kinase inhibitors and antiangiogenic agents.
abstract: Direct and indirect involvement of receptor tyrosine kinases (RTKs) in tumor growth and metastasis makes them ideal targets for anticancer therapy. A paradigm shift from inhibition of single RTK to inhibition of multiple RTKs has been recently demonstrated. We designed and synthesized eight N(4)-phenylsubstituted-6-(2-phenylethylsubstituted)-7H-pyrrolo[2,3-d]pyrimidine-2,4-diamines as homologated series of our previously published RTK inhibitors. We reasoned that increased flexibility of the side chain, which determines potency and selectivity, would improve the spectrum of RTK inhibition. These compounds were synthesized using a bis-electrophilic cyclization to afford substituted pyrrolo[2,3-d]pyrimidines followed by chlorination and substitution at the 4-position with various anilines. Five additional compounds of this series were previously reported by Gangjee et al.(1) with activities against IGFR only. Their synthesis, characterization and biological activities against a variety of other RTKs are reported in this study for the first time. The biological evaluation, in whole cell assays, showed several analogs had remarkable inhibitory activity against epithelial growth factor receptor (EGFR), vascular endothelial growth factor receptor-1 (VEGFR-1), platelet-derived growth factor receptor-beta (PDGFR-beta), the growth of A431 cells in culture, and in the chicken embryo chorioallantoic membrane (CAM) angiogenesis assay. The inhibitory data against the RTKs in this study demonstrate that variation of the 6-ethylaryl substituents as well as the N(4)-phenyl substituents of these analogs does indeed control both the potency and specificity of inhibitory activity against RTKs. In addition, homologation of the chain length of the 6-substituent from a methylene to an ethyl increases the spectrum of RTK inhibition. New multi-RTK inhibitors (8, 12) and potent inhibitors of angiogenesis (15, 19) were identified with the best compound, N(4)-(3-trifluromethylphenyl)-6-(2-phenylethyl)-7H-pyrrolo[2,3-d]pyrimidine-2,4-diamine (15), with an IC(50) value of 30nM in the CAM angiogenesis inhibition assay.
authors.affiliation: Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA. gangjee@duq.edu
authors.forename: Aleem
authors.initials: A
authors.lastname: Gangjee
authors.forename: Ojas A
authors.initials: OA
authors.lastname: Namjoshi
authors.forename: Jianming
authors.initials: J
authors.lastname: Yu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Ihnat
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Thorpe
authors.forename: Linda A
authors.initials: LA
authors.lastname: Warnke
mesh_terms: D020533:Angiogenesis Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000187:drug effects; D015195:Drug Design; D004354:Drug Screening Assays, Antitumor; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D006801:Humans; D008958:Models, Molecular; D015394:Molecular Structure; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011743:Pyrimidines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000037:antagonists & inhibitors; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000037:antagonists & inhibitors
chemical_list: D020533:Angiogenesis Inhibitors; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D011758:Pyrroles; C450639:Pyrrolo(2,3-d)pyrimidine; D066246:ErbB Receptors; D020794:Receptor Protein-Tyrosine Kinases; D020797:Receptor, Platelet-Derived Growth Factor beta; D040281:Vascular Endothelial Growth Factor Receptor-1