The conformational analysis of saturated heterocycles. Part XXI. Dipole moment studies of 1-ethyl- and 1-isopropyl-piperidines and further studies of 1-methylpiperidines

Abstract

Further measurements indicate a conformational free-energy difference of ca. 0·65 kcal./mole for an N-methyl group in the piperidine ring system in favour of the methyl group equatorial, and values of 0·9 and 1·4 kcal./mole, respectively, for N-ethyl and N-isopropyl groups. These values are discussed in comparison with literature data.