title: Synthesis of pyrazole containing α-amino acids via a highly regioselective condensation/aza-Michael reaction of β-aryl α,β-unsaturated ketones.
abstract: A synthetic approach for the preparation of a new class of highly conjugated unnatural α-amino acids bearing a 5-arylpyrazole side-chain has been developed. Horner-Wadsworth-Emmons reaction of an aspartic acid derived β-keto phosphonate ester with a range of aromatic aldehydes gave β-aryl α,β-unsaturated ketones. Treatment of these with phenyl hydrazine followed by oxidation allowed the regioselective synthesis of pyrazole derived α-amino acids. As well as evaluating the fluorescent properties of the α-amino acids, their synthetic utility was also explored with the preparation of a sulfonyl fluoride derivative, a potential probe for serine proteases.
authors.affiliation: WestCHEM, School of Chemistry, The Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK. Andrew.Sutherland@glasgow.ac.uk.
authors.forename: Lynne
authors.initials: L
authors.lastname: Gilfillan
authors.forename: Raik
authors.initials: R
authors.lastname: Artschwager
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Harkiss
authors.forename: Rob M J
authors.initials: RM
authors.lastname: Liskamp
authors.forename: Andrew
authors.initials: A
authors.lastname: Sutherland
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry; D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D000596:Amino Acids; D005456:Fluorescent Dyes; D007659:Ketones; D011720:Pyrazoles; C031280:pyrazole