83097-67-0Relevant academic research and scientific papers
Crystal and Molecular Structure of Tetraaryl-3,7-diazabicyclononanes and Tetra- and Pentaaryl-1,3-diazaadamantanes. Chair-Boat Conformation of the Tetraaryl-3,7-diazabicyclononanes
Quast, Helmut,Mueller, Bodo,Peters, Eva-Maria,Peters, Karl,Schnering, Hans Georg von
, p. 3631 - 3652 (2007/10/02)
The 2,4,6,8-tetrakis(3,5-dimethylphenyl)-3,7-diazabicyclononanes 8c and 10c, the 1,3-diazaadamantanes 11c and 13c derived therefrom, and some tetraaryl-3,7-diazabicyclononanes methylated at one (14b, 16b) or both nitrogen atoms (15b, c, 17b, c, 19) have been synthesized for structure and NMR studies.N-Methylation occured regioselectively at the piperidine ring existing in the boat conformation.The nitrogen atom of the piperidine ring in the chair conformation was methylated only under forced conditions.With 4-methylbenzaldehyde, 8b formed slowly the pentakis(4-methylphenyl)-1,3-diazaadamantanone 12b, in which the configuration of one of the benzylic carbon atoms of the piperidine ring in the chair conformation had changed.By means of X-ray analysis of the 3,7-diazabicyclononanes 8c, 15b, and 16b as well as of the 1,3-diazaadamantanones 12b and 20 the structures were determined and the preferred conformations, especially those of the aryl groups, in the crystalline state were established.Accordingly, all tetraaryl-3,7-diazabicyclononanes exist in the chair-boat conformation with equatorial aryl groups.Two of the five aryl substituents in 12b occupy a 1,3-diaxial position while the three neighbouring aryl groups exhibit an unexpected propeller-like arrangement.
