title: Synthesis and transformations of novel L-phenylalanine derived pyrazolidin-3-ones.
abstract: A simple and straightforward four-step synthesis of novel diastereomeric L-phenylalanine-derived pyrazolidin-3-ones is described. The absolute configuration of the novel C(5) stereogenic centre has been unambiguously determined by single crystal X-ray analysis and via chemical interconversions. A series of novel thiourea derived pyrazolidinones have been prepared and tested as potential organocatalysts. N(1) un-substituted pyrazolidinones can be used for the construction of a novel type of bicyclic heterocycles and other selective derivatizations.
authors.affiliation: University of Ljubljana, Faculty of Chemistry and Chemical Technology, Aškerčeva cesta 5, P.O. Box 537, SI-1000 Ljubljana, Slovenia. uros.groselj@fkkt.uni-lj.si
authors.forename: Uroš
authors.initials: U
authors.lastname: Grošelj
authors.forename: Amalija
authors.initials: A
authors.lastname: Golobič
authors.forename: Jurij
authors.initials: J
authors.lastname: Svete
authors.forename: Branko
authors.initials: B
authors.lastname: Stanovnik
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D010649:Phenylalanine / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D011720:Pyrazoles; D010649:Phenylalanine
keywords: (thio)ureas; hydrazine cyclization; pyrazolidin-3-ones; tetrahydro-1H-imidazo[1,5-b]pyrazole-2,6-dione; β-keto ester