title: Conformational features of secondary N-cyclopropyl amides.
abstract: NMR studies in conjunction with ab initio calculations revealed unexpected conformational behavior of N-cyclopropylacetamide (1). This secondary amide displays 16-19% E-rotamer (cis) around the carbonyl-nitrogen bond in apolar solvents, in contrast to other aliphatic secondary acetamides in which significant E-rotamer populations are rare due to steric contacts between the substituents on the amide bond. In addition, 1 adopts an ortho conformation around the N-cPr bond instead of the anti conformation generally preferred by secondary acetamides. This distinct conformational behavior was also observed for other secondary N-cyclopropyl amides.
authors: Centro de Investigación Lilly, Avda. de la Industria, 30, 28108-Alcobendas, Madrid, Spain.
authors: Ángela
authors: Á
authors: González-de-Castro
authors: Centro de Investigación Lilly, Avda. de la Industria, 30, 28108-Alcobendas, Madrid, Spain.
authors: Howard
authors: H
authors: Broughton
authors: Centro de Investigación Lilly, Avda. de la Industria, 30, 28108-Alcobendas, Madrid, Spain.
authors: José A
authors: JA
authors: Martínez-Pérez
authors: Centro de Investigación Lilly, Avda. de la Industria, 30, 28108-Alcobendas, Madrid, Spain.
authors: Juan F
authors: JF
authors: Espinosa