title: Synthesis of [beta-(4-pyridyl-1-oxide)-L-alanine4]-angiotensin I as a potential suicide substrate for protein-tyrosine kinases.
abstract: An asymmetric synthesis of [beta-(4-pyridyl-1-oxide)-L-alanine4]-angiotensin I (1a), which is a potential suicide substrate (mechanism-based inhibitor) for protein-tyrosine kinases, has been performed. Deprotonation of 6 with n-butyllithium in THF gave the anion 7, which was alkylated with 4-(chloromethyl)pyridine-1-oxide to afford intermediate 9 as a crystalline solid. Hydrolysis of 9 afforded a mixture of 11 and 12 in a ratio of 96:4 as estimated by conversion to the diastereomeric dipeptides 13 and 14 followed by HPLC analysis. The 96:4 mixture of 11 and 12 was used in the solid phase synthesis of the target angiotensin analog 1a and its diastereomer 1b, which were separated and tested for inhibitory activity against two thymocyte protein-tyrosine kinases: p40 and p56lck. Neither peptide displayed significant inhibitory activity toward p40 and both served as weak competitive inhibitors of p56lck.
authors.affiliation: Department of Medicinal Chemistry and Pharmacognosy, Purdue University, West Lafayette, Indiana.
authors.forename: M
authors.initials: M
authors.lastname: Cushman
authors.forename: P
authors.initials: P
authors.lastname: Chinnasamy
authors.forename: A K
authors.initials: AK
authors.lastname: Chakraborti
authors.forename: J
authors.initials: J
authors.lastname: Jurayj
authors.forename: R L
authors.initials: RL
authors.lastname: Geahlen
authors.forename: R D
authors.initials: RD
authors.lastname: Haugwitz
mesh_terms: D000803:Angiotensin I / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*
chemical_list: C068661:angiotensin I, (beta-(4-pyridyl-1-oxide)-Ala(4))-; D000803:Angiotensin I; D011505:Protein-Tyrosine Kinases