Hantzsch Synthesis of Pyrazolo[1‘,2‘:1,2]pyrazolo[3,4-b]pyridines: Partial Agonists of the Calcitonin Receptor
journal contributionposted on 24.06.2005, 00:00 by Eric E. Boros, David J. Cowan, Richard F. Cox, Makda M. Mebrahtu, Michael H. Rabinowitz, James B. Thompson, Lawrence A. Wolfe
Small molecule calcitonin receptor agonists are of potential utility in the treatment and prevention of osteoporosis. Bicycloeneamine 1 was a useful intermediate in the synthesis of pyrazolopyridine calcitonin receptor partial agonists 2a−f. Dihydropyridines 10a−c were conveniently prepared by reaction of 1 with Knoevenagel adducts 9a−c, or in the case of 10d, by a three component reaction with 1, β-ketoester 7b, and aldehyde 8c. Oxidation of 10a−d to pyridines 11a−d and subsequent amide formation afforded the title compounds.
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Calcitonin ReceptorKnoevenagel adducts 9agonists 2ketoesterpyridines 11utilitysynthesisaldehyde 8 cHantzsch Synthesisamide formationDihydropyridines 10Pyrazoloosteoporosismolecule calcitonin receptor agonistsAgonistBicycloeneamine 1title compoundsPartialOxidationpyrazolopyridine calcitonin receptorcomponent reactionprevention