02284nas a2200253 4500008004100000022001400041245013800055210006900193260007300262300001000335490000800345520134600353653001101699653001701710653001801727653002001745653002301765653002001788100002901808700002701837700002601864700002101890856011901911 2011 eng d a0022-286000aFacile synthesis of N-benzylated 3-alkyl-2,6-diarylpiperidin-4-ones: Stereochemical investigation by 1D/2D NMR and single-crystal XRD0 aFacile synthesis of Nbenzylated 3alkyl26diarylpiperidin4ones Ste aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a44-560 v9903 a

A series of thirteen 1-benzyl-3-alkyl-2,6-diarylpiperidin-4-ones 14-26 were conveniently synthesized in high yields 87-92%. In order to find the impact on piperidone stereochemistry, beside the N-benzylation, methyl/ethyl/isopropyl groups at C-3 and halo/alkyl/alkoxy/benzyloxy groups on the phenyl rings at C-2/C-6 were introduced. All the synthesized compounds were characterized by mass, (1)H and (13)C NMR spectral studies. Of them, the 1-benzyl-3-ethyl-2,6-diphenylpiperidin-4-one 22 was completely characterized by 2D NMR techniques such as (1)H-(1)H COSY, (1)H-(13)C COSY and NOESY to assign the signals, unambiguously. The proton coupling constants and NOE correlations provided the complete stereochemistry of 22, which is further witnessed by its single-crystal XRD analysis. The NMR and XRD studies revealed that the compound 22 exists in a chair conformation with equatorial orientation of all the substituents in both solution and solid states. On the basis of their vicinal coupling constants, the chair conformation with equatorial orientation of the substituents at C-2, C-3, C-6 and N is proposed for all compounds 14-26; moreover, a considerable population of boat conformation also suggested for the compound 26 along with the predominant chair conformation, in solution. (C) 2011 Elsevier B.V. All rights reserved.

10a2D NMR10aConformation10aN-benzylation10aPiperidin-4-one10asingle-crystal XRD10aStereochemistry1 aDindulkar, Someshwar, D.1 aParthiban, Paramasivam1 aPuranik, Vedavati, G.1 aJeong, Yeon, Tae uhttp://library.ncl.res.in/content/facile-synthesis-n-benzylated-3-alkyl-26-diarylpiperidin-4-ones-stereochemical-002681nas a2200253 4500008004100000022001400041245007200055210006900127260007300196300001200269490000900281520182000290653002302110653001802133653002202151653001802173653000802191653002002199100002902219700002702248700002602275700002102301856010502322 2012 eng d a0022-286000aSynthesis and stereochemistry of highly crowded N-benzylpiperidones0 aSynthesis and stereochemistry of highly crowded Nbenzylpiperidon aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN a158-1670 v10073 a

A series of N-benzylated 3,5-diakyl-2,6-diarylpiperidin-4-ones 4-8 were conveniently synthesized in significant yields of 68-88% by N-benzylation of the corresponding 2,6-diaryl-3,5-dimethylpiperidin-4-ones 1-3 using different benzyl bromides. Initially, the new piperidone 2,6-bis(4-ethoxypheny1)-3,5-dimethylpiperidin-4-one 3 was synthesized by the condensation of 1:1:2 M ratio of 3-pentanone, ammonium acetate and para-ethoxybenzaldehyde in ethanolic medium. All the synthesized new compounds 3-8 were characterized by their analytical and spectral (IR, H-1 and C-13 NMR) interpretations. The stereochemistry of the new piperidone 3 was elucidated as chair conformation with an equatorial orientation of all substituents, suggested by its vicinal couplings from H-1 NMR spectrum. To investigate the impact on piperidone stereochemistry as well as NMR chemical shifts, all the N-benzylated products 4-8 were compared with their corresponding precursors, and as a result, it is clearly established that all the synthesized N-benzyl piperidones exist in the chair conformation with an equatorial orientation of all the substituents at C-2, C-3, C-5, C-6 and N. Contrary to the probability all N-benzylated compounds retain the same conformation and configuration as their precursors, however, a remarkable change on the chemical shifts are observed. For the further unambiguous confirmation of stereochemistry, the 1-benzyl-3,5-dimethyl-2,6-diphenylpiperidin-4-one 4 was examined by single-crystal X-ray diffraction. The compound 4, C26H27NO, crystallized in a P-1 space group under triclinic system with unit cell dimensions a, b, c (angstrom) and alpha, beta, gamma (degrees) of 10.156(2), 11.002(2), 11.348(4) and 116.74(4), 100.81(3), 100.17(3), respectively. (C) 2011 Elsevier B.V. All rights reserved.

10aChair conformation10aConfiguration10acrystal structure10aN-benzylation10aNMR10aPiperidin-4-one1 aDindulkar, Someshwar, D.1 aParthiban, Paramasivam1 aPuranik, Vedavati, G.1 aJeong, Yeon, Tae uhttp://library.ncl.res.in/content/synthesis-and-stereochemistry-highly-crowded-n-benzylpiperidones-001781nas a2200277 4500008004100000022001400041245011000055210006900165260010200234300001200336490000800348520074900356653001701105653001501122653003501137653002301172100002901195700001901224700002301243700002601266700001701292700002001309700002701329700002101356856012601377 2014 eng d a0974-362600aDesign, synthesis and cytotoxicity of novel N-benzylpiperidin-4-one oximes on human cervical cancer cells0 aDesign synthesis and cytotoxicity of novel Nbenzylpiperidin4one  aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScMAY a861-8730 v1263 a

A series of fifteen diversified N-benzylpiperidin-4-one oximes were synthesized and characterized by their NMR spectral data. Additionally, single-crystal XRD analysis was performed for the representative symmetrically and unsymmetrically substituted molecules. All the synthesized oximes from unsymmetrical ketones existed as E-isomer as witnessed by their NMR and XRD data. Among the synthesized target compounds that evaluated for their in vitro cytotoxicity against human cervical carcinoma (HeLa) cells, five compounds were potent with IC50 < 17 mu M. 1-Benzyl-2,6-bis(4-isopropylphenyl)-3-methylpiperidin-4-one oxime 3c with an IC50 of 13.88 mu M was found to be the best active compound as depicted by the microscopic analysis.

10aCytotoxicity10aHeLa cells10aN-benzylpiperidin-4-one oximes10asingle-crystal XRD1 aDindulkar, Someshwar, D.1 aBhatnagar, Ira1 aGawade, Rupesh, L.1 aPuranik, Vedavati, G.1 aKim, Se-Kwon1 aAnh, Dong, Hyun1 aParthiban, Paramasivam1 aJeong, Yeon, Tae uhttp://library.ncl.res.in/content/design-synthesis-and-cytotoxicity-novel-n-benzylpiperidin-4-one-oximes-human-cervical-0