2162-86-9Relevant articles and documents
Eclipsed Conformation of the Exocyclic N-CH2 Bond in N-Neopentylpiperidines and the Stereodynamic Consequences As Studied by Dynamic NMR Spectroscopy and Molecular Mechanics Calculations
Anderson, J. Edgar,Ijeh, Anthony I.,Storch, Christine,Casarini, Daniele,Lunazzi, Lodovico
, p. 3310 - 3317 (2007/10/03)
The dynamic stereochemistry of a range of N-neopentylpiperidines 1 with an eclipsed N-CH2-t-Bu bond is compared with that of the corresponding range of N-ethylpiperidines 2 with a gauche N-CH2Me bond. By using dynamic NMR spectroscopy, the relative importance of ring inversion, exocyclic bond rotation, and nitrogen inversion are elucidated and barriers are reported and discussed. Minor populations of the neopentyl-axial-eclipsed conformation are detected directly and identified with the help of molecular mechanics calculations. The corresponding N-alkylpyrrolidines are also reported.
Piperidylidene derivatives of carboxy-5H-dibenzo[a,d]cycloheptene
-
, (2008/06/13)
The new 1-alkyl-4-(1, 2, or 3-carboxy-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine compounds are prepared from the corresponding 1, 2 or 3-carboxy-5H-dibenzo[a,d]cyclohepten-5-one by reaction with a Grignard reagent prepared from a 1-alkyl-4-halo piperidine to form an intermediate carbinol, or a 1, 2 or 3-carboxy-5-(1-alkyl-4-piperidyl)-5H-dibenzo[a,d]cyclohepten-5-ol which is then dehydrated to produce the desired 1-alkyl-4-(1, 2 or 3-carboxy-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine, or alternatively by hydrolysis of a 1-alkyl-4-(1, 2 or 3-cyano-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine compound to form the corresponding 1-alkyl-4-(1, 2 or 3-carboxy-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine compound.
