Synthesis, crystal structure, DFT calculations and Hirshfeld surface analysis of 3-butyl-2,6-bis-(4-fluoro-phen-yl)piperidin-4-one

The title compound, C21H23F2NO, consists of two fluoro-phenyl groups and one butyl group equatorially oriented on a piperidine ring, which adopts a chair conformation. The dihedral angle between the mean planes of the phenyl rings is 72.1 (1)°. In the crystal, N-H⋯O and weak C-H⋯F inter-actions, which form R 2 2[14] motifs, link the mol-ecules into infinite C(6) chains propagating along [001]. A weak C-H⋯π inter-action is also observed. A Hirshfeld surface analysis of the crystal structure indicates that the most significant contributions to the crystal packing are from H⋯H (53.3%), H⋯C/C⋯H (19.1%), H⋯F/F⋯H (15.7%) and H⋯O/O⋯H (7.7%) contacts. Density functional theory geometry-optimized calculations were compared to the experimentally determined structure in the solid state and used to determine the HOMO-LUMO energy gap and compare it to the UV-vis experimental spectrum.

Novel asymmetric 3,5-bis(arylidene)piperidin-4-one derivatives: synthesis, crystal structures and cytotoxicity

3,5-Bis(arylidene)piperidin-4-one derivatives (BAPs) display good antitumour activity because of their double α,β-unsaturated ketone structural characteristics. Reported BAPs have generally been symmetric and asymmetric BAPs have been little documented. Three asymmetric BAPs, namely (5E)-3-(4-tert-butylbenzylidene)-5-(4-fluorobenzylidene)-1-methylpiperidin-4-one, C₂₄H₂₆FNO, (5), (5E)-3-(4-tert-butylbenzylidene)-5-(3,5-dimethoxybenzylidene)-1-methylpiperidin-4-one, C₂₆H₃₁NO₃, (6), and (5E)-3-{3-[(E)-(2,3-dihydroxybenzylidene)amino]benzylidene}-5-(2-fluorobenzylidene)-1-methylpiperidin-4-one, C₂₇H₂₃FN₂O₃, (12), were generated by Claisen-Schmidt condensation. They are characterized by NMR and FT-IR spectroscopies, and elemental analysis. Single-crystal structure analysis reveals that the two arylidene rings on both sides of the BAP structures adopt an E stereochemistry of the olefinic double bonds and the compounds are E,E isomers. Molecules of (5) and (12) generate one-dimensional chains through intermolecular hydrogen bonds, while compound (6) generates a two-dimensional network through hydrogen bonds. Preliminary cytotoxicities toward human liver hepatocellular carcinoma cell line (HepG2), human acute mononuclear granulocyte leukaemia (THP-1) and human normal hepatical cell line (LO2) were evaluated.

Crystal structure of 1-(2-chloro-acet-yl)-3,3-dimethyl-2,6-di-p-tolyl-piperidin-4-one

In the title compound, C23H26ClNO2, the piperidin-4-one ring adopts a distorted boat conformation. The two p-tolyl rings are nearly normal to each other, making a dihedral angle of 83.33 (10)°. They are inclined to the mean plane of the piperidine ring by 73.2 (1) and 87.22 (9)°. In the crystal, there are no significant inter-molecular inter-actions present.

Stereochemical effect on biological activities of new series of piperidin-4-one derivatives

New series of (2S,3R,4S,6R)-3-methyl-4-alkyl-2,6-diarylpiperidin-4-ol were synthesised by the reduction of cis-3-alkyl-2,6-diarylpiperidin-4-one using Grignard reagent. The structural assignments and conformational studies of the synthesised compounds were established based on the IR, (1)H NMR, (13)C NMR, NOESY and mass spectral studies. Their stereochemical effect on antibacterial, antifungal and anthelmintic activities was studied.

Crystal structure of 2,6-bis-(2,5-di-meth-oxy-phen-yl)-3,5-di-methyl-piperidin-4-one

In the title mol-ecule, C23H29NO5, the central piperidine ring has a chair conformation. The planes of the two benzene rings are inclined each to other at 61.7 (1)°. The crystal packing exhibits no directional inter-actions only van der Waals contacts.