title: A Michael Equilibration Model To Control Site Selectivity in the Condensation toward Aminopyrazoles.
abstract: A Michael equilibration model is presented to provide for site-selective pyrazole condensations between alkoxyacrylonitriles and hydrazines. Both pyrazole isomers were accessed with high selectivity by employment of kinetically or thermodynamically controlled conditions. Substrate scope and identification of Michael intermediates, as well as competitive pathways, support the presented mechanistic proposal. Sandmeyer derivatization provided site-selective access to fully substituted pyrazoles.
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Fandrick
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Sanjit
authors.initials: S
authors.lastname: Sanyal
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Kaloko
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Mulder
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Yuwen
authors.initials: Y
authors.lastname: Wang
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Ling
authors.initials: L
authors.lastname: Wu
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Heewon
authors.initials: H
authors.lastname: Lee
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Frank
authors.initials: F
authors.lastname: Roschangar
authors.forename: Matthias
authors.initials: M
authors.lastname: Hoffmann
authors.affiliation: †Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, United States.
authors.forename: Chris H
authors.initials: CH
authors.lastname: Senanayake
mesh_terms: D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D011720:Pyrazoles