75549-52-9Relevant academic research and scientific papers
Stereocontrolled facile synthesis and antimicrobial activity of oximes and oxime ethers of diversely substituted bispidines
Parthiban, Paramasivam,Kabilan, Senthamaraikannan,Ramkumar, Venkatachalam,Jeong, Yeon Tae
supporting information; experimental part, p. 6452 - 6458 (2010/12/18)
A small library of diversely substituted 2,4,6,8-tetraaryl-3,7- diazabicyco[3.3.1]nonan-9-ones, their oximes and O-methyloximes were achieved in a stereocontrolled manner by an easiest synthetic strategy as single isomers with high yields. Stereochemistry of all the synthesized compounds was established by their 1D/2D NMR spectral studies, further, witnessed by single-crystal XRD analysis. Accordingly, the compounds exist in a chair-boat conformation with equatorial orientation of the substituents in the chair part and boat-axial orientation in the boat part. Finally, all the synthesized oximes and oxime ethers were evaluated for their in vitro antimicrobial activity against a panel of pathogenic bacteria and fungi, and as a result of the structure-activity correlations, some lead molecules were known for further optimization.
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.
Stereochemistry of Tetraaryl-3,7-diazabicyclononanes and Tetraaryl-1,3-diazaadamantanes
Quast, Helmut,Mueller, Bodo
, p. 2959 - 2975 (2007/10/02)
By means of paraformaldehyde, the 2,4,6,8-tetraaryl-3,7-diazabicyclononanones 7 = 19 of known constitution have been converted to the 1,3-diazaadamantanes 9 = 17 and 10 = 18, respectively, either directly or after previous Wolff-Kishner reduction.The IR and NMR spectra prove the rel-(2S, 4R, 6R, 8S)-configuration of the diazabicyclononanes 19 and 20 and the rel-(4R, 8S, 9R, 10S)-configuration of the corresponding 1,3-diazaadamantanes 17 and 18.These served as models in an 1H NMR spetroscopic investigation of the diazabicyclononanes 19 and 20, which exist in the chair-chair conformation, one chair having a pair of axial the other a pair of equatorial aryl groups.The reaction of the cis-2,6-diphenylpiperidone 6a with benzaldehyde or 4-methylbenzaldehyde and the reaction of 6b with benzaldehyde inevitably yielded mixtures of type 19, R4 = Ar14-nAr2n(n = 0-4), since in part the aldehydes are incorporated into the piperidones 6.The (equatorial) aryl groups of the piperidones 6 prefer the axial positions in the diazabicyclononanes 19.The diastereoselective formation of the diazabicyclononanes 21 and 22 is compared to that of 8-oxosparteine (27) and traced back to the greater stability of the all-trans-substituted piperidone intermediate trans-28.
