Synthesis of pyrazolo[1,5-α]pyrimidine regioisomers

ORGN 308

Arthur Lee, alee@wyeth.com, Chemical and Screeening Sciences, Wyeth Research, 200 Cambridge Park Dr, Cambridge, MA 02140, Lori Krim Gavrin, gavrinl@wyeth.com, Medicinal Chemistry, Chemical and Screening Sciences, Wyeth Research, 500 Arcola Rd., Collegeville, PA 02140, Brian A. Provencher, provencherb@gmail.com, Summer Intern, Wyeth Research, 44B Elm St., Woburn, MA 01801, and John C McKew, jmckew@wyeth.com, Department of Chemical and Screening Sciences, Wyeth Research, 200 CambridgePark Drive, Cambridge, MA 02140.
This work surveys complementary routes for the synthesis of pyrazolo[1,5-α]pyrimidine-7-ones (1) and pyrazolo[1,5-α]pyrimidin-5-ones (2). The use of 1,3-dimethyluracil (3) as an electrophile for pyrimidine ring construction affords pyrazolo[1,5-α]pyrimidin-5-ones (2), contrary to literature reports. Novel use of trans-3-ethoxyacrylate (4) as an electrophile also afforded (2) and isolated intermediates from this reaction support our proposed mechanism.

 

Heterocycles and Aromatics
8:00 AM-12:00 PM, Tuesday, March 27, 2007 McCormick Place Lakeside -- Room E350, Level 3, Oral

Division of Organic Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007