title: Synthesis of pyrazolo[1,5-alpha]pyrimidinone regioisomers.
abstract: This work describes two distinct routes to prepare pyrazolo[1,5-alpha]pyrimidin-7-ones and two distinct routes to prepare pyrazolo[1,5-alpha]pyrimidin-5-ones. Use of 1,3-dimethyluracil as the electrophile in the preparation of the pyrimidin-5-one regioisomer represents a correction of previously reported results. Also, a novel reaction to prepare this isomer was identified and the reaction mechanism elucidated. This work provides the experimentalist with complimentary synthetic pathways that afford either the pyrimidin-7-one or the pyrimidin-5-one regioisomer.
authors.affiliation: Department of Exploratory Medicinal Chemistry and Chemical Technologies, Wyeth Research, 200 CambridgePark Drive, Cambridge, Massachusetts 02140, USA. gavrinl@wyeth.com
authors.forename: Lori K
authors.initials: LK
authors.lastname: Gavrin
authors.forename: Arthur
authors.initials: A
authors.lastname: Lee
authors.forename: Brian A
authors.initials: BA
authors.lastname: Provencher
authors.forename: Walter W
authors.initials: WW
authors.lastname: Massefski
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Huhn
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Ciszewski
authors.forename: Derek C
authors.initials: DC
authors.lastname: Cole
authors.forename: John C
authors.initials: JC
authors.lastname: McKew
mesh_terms: D000893:Anti-Inflammatory Agents / Q000138:chemical synthesis*; D007536:Isomerism; D008956:Models, Chemical; D011720:Pyrazoles / Q000737:chemistry*; D011744:Pyrimidinones / Q000737:chemistry*; D012556:Schistosomicides / Q000138:chemical synthesis; D014498:Uracil / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000893:Anti-Inflammatory Agents; D011720:Pyrazoles; D011744:Pyrimidinones; D012556:Schistosomicides; D014498:Uracil; C002451:1,3-dimethyluracil