4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy phenyl)piperidine-4-one (1)

Transcription

1 4 Piperidine derivatives acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy phenyl)piperidine-4-one (1) Synthesis To a well stirred solution of 3-methyl-2,6-bis(3,4,5-trimethoxyphenyl)piperi dine-4-one (5 mmol) and trimethylamine(5 mmol) in 30 ml of benzene, 3- chloropropanoyl chloride (5 mmol) in 20 ml benzene was added drop wise through the addition funnel for about an hour. The resulting mixture was stirred for about 4 hours under room condition. After the completion of the reaction the mixture was quenched in cold water and the organic layer was extracted into ethyl acetate, washed with 5% sodium bicarbonate solution and dried over anhydrous sodium sulphate. This upon evaporation and recrystallisation in alcohol yielded 2,6-bis(3,4,5-trimethoxyphenyl)-1- (3-chloropropanoyl) -3,5-dimethylpiperidine-4-one. Further the crystals were dissolved in ethanol (60 ml), refluxed for half an hour and allowed to crystallize by slow evaporation. The schematic diagram of the molecule is shown in figure 4.1.

2 102 Piperidine derivatives O H 3 C CH 3 CH 3 O N O H 3 C O O O CH 3 H 3 C O CH 2 O CH 3 Figure 4.1: Schematic diagram Crystal and molecular structure A white rectangular crystal of C 27 H 33 NO 8, with dimensions of mm was chosen for X-ray diffraction study. The procedures employed for data collection and data reduction are given in section 3.1. The structure was solved by direct methods using SHELXS All the frames could be indexed using a primitive orthorhombic lattice phase sets were refined with the best phase set having a CFOM of Using the normalised structure factors with these phases, a total of 1390 phases were generated. The final RE value turned out to be No absorption corrections were applied. All the non-hydrogen atoms were revealed in the first Fourier map itself. Full-matrix least squares refinement using SHELXL-97 1 with isotropic temperature factors for all the atoms converged the residual to R 1 = Refinement of the non-hydrogen atoms with anisotropic parameters was started at this stage. The hydrogen atoms were placed at chemically acceptable positions and were allowed to ride on the parent atoms. 333 parameters were refined with 3711 unique reflections which saturated the residual R 1 = The details of the crystal data and refinement are given in Table 4.1. The

3 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy ORTEP 2 of the molecule with thermal ellipsoids drawn at 50% probability is shown in figure 4.2. The final atomic coordinates and equivalent thermal parameters of the non-hydrogen and the hydrogen atoms are listed in Tables 4.2 and 4.3, respectively. Table 4.4 gives the anisotropic thermal parameters of the non-hydrogen atoms. Tables give the list of bond distances and bond angles of non-hydrogen atoms, respectively. Table 4.7 gives the list of torsion angles. The bond lengths and bond angles of all the non-hydrogen atoms are in good agreement with the standard values. 3 The ring-puckering analysis 4 (Cremer and Pople, 1975) of six-membered ring in the molecule indicates that the ring adopts a twist boat conformation, 5 with a puckering amplitude Q = 0.650(4)Å, θ= 91.6(4) and φ =248.1(4). Atoms C2 and C6 deviate from the plane (Cremer and Pople, 1975) defined by the atoms N1/C2/C3/C4/C5/C6 by 0.379(4)Åand (4)Å, respectively. The pipe ridine ring in the molecule 1-acroyl-2,6-bis (3,4,5-trimethoxy phenyl) piperid ine-4-one has a weighted average torsion angle of The substituent at C2 is in equatorial conformation as indicated by the dihedral angle of 84.2(2) between piperidine ring and phenyl ring and the substituent at C6 between the piperidine and phenyl ring has dihedral angle of 71.68(2). The torsion angle value of (3) for N1-C6-C5-C8 indicates that methyl group substituted at C5 is oriented in -anti-periplanar conformation. The torsion angle value of 174.6(3) for C6-N1-C9-O10 indicates that O10 is oriented in +anti-periplanr conformation. The acryloyl group substituted at N1 is oriented in +anti-periplanr confornmation as indicated by the torsion angle value of 165.6(3) for C2-N1-C9-C11. The methoxy groups substituted at C27, C29, C17 and C15 are nearly planar with the phenyl ring whereas the methoxy groups substituted at C28 and C16 are nearly orthogonal as indicated by the torsion angles (Table 4.7). The molecules are linked into complex two-dimensional structure by intermolecular hydrogen bonds 6 of the type C H O as shown in table 4.8. The packing of the molecules when viewed down the a, b and c axes are shown in figures 4.3, 4.4 and 4.5

4 104 Piperidine derivatives Table 4.1: Crystal data and structure refinement table for (1) Empirical formula C 27 H 33 NO 8 Formula weight Temperature 293(2)K Wavelength Å Crystal system Orthorhombic Space group Pbca Cell dimensions a = (4)Å b = (2)Å c = (6)Å Volume 5212(2)Å 3 Z 8 Density(calculated) Mg/m 3 Absorption coefficient mm 1 F Crystal size mm Theta range for data collection 2.62 to Index ranges 14 h k l 27 Reflections collected 6343 Independent reflections 3711 [R(int) = ] Absorption correction None Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 3711 / 0 / 333 Goodness-of-fit on F Final R indices [I > 2σ(I)] R1 = , wr2 = R indices (all data) R1 = , wr2 = Extinction coefficient (12) Largest diff. peak and hole and e.å 3

5 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Table 4.2: Atomic coordinates and equivalent thermal parameters of the nonhydrogen atoms for (1). Atom x y z U eq N (2) (2) (1) (8) C (3) (2) (1) (1) C (3) (3) (1) (1) C (4) (3) (2) (1) C (3) (3) (2) (1) C (3) (2) (1) (1) O (3) (3) (2) (1) C (4) (3) (2) (1) C (3) (3) (1) (1) O (2) (2) (1) (1) C (3) (3) (2) (1) C (5) (3) (3) (2) C (3) (2) (1) (1) C (3) (2) (1) (1) C (3) (2) (1) (1) C (3) (2) (1) (1) C (3) (2) (1) (1) C (3) (2) (1) (1) O (2) (2) (1) (9) C (3) (3) (2) (1) O (2) (2) (1) (8)

6 106 Piperidine derivatives Table 4.2 (continued) Atom x y z U eq C (3) (3) (2) (1) O (2) (2) (1) (9) C (3) (3) (2) (1) C (3) (3) (1) (1) C (3) (3) (1) (1) C (3) (3) (2) (1) C (3) (2) (1) (1) C (3) (3) (1) (1) C (3) (2) (1) (1) O (2) (2) (1) (9) C (4) (3) (2) (1) O (2) (2) (1) (9) C (4) (3) (2) (2) O (2) (2) (1) (1) C (4) (3) (2) (2) U eq = (1/3) i U ij (a i a j )(a i.a j ) j

7 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Table 4.3: Atomic coordinates and equivalent thermal parameters of the hydrogen atoms for (1). Atom x y z U eq H H H5A H5B H H7A H7B H7C H11A H11B H12A H12B H12C H H H H20A H20B H20C

8 108 Piperidine derivatives Table 4.3 (continued) Atom x y z U eq H22A H22B H22C H24A H24B H24C H H31A H31B H31C H33A H33B H33C H35A H35B H35C

9 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Table 4.4: Anisotropic thermal parameters of the non-hydrogen atoms for (1). Atom U 11 U 22 U 33 U 12 U 13 U 23 N (2) 0.069(2) 0.040(2) (1) (1) (1) C (3) 0.079(3) 0.054(2) 0.003(2) (2) (2) C (3) 0.097(4) 0.069(3) 0.011(2) (2) (2) C (4) 0.086(4) 0.067(3) 0.023(3) (3) (2) C (4) 0.071(3) 0.052(2) (2) (2) 0.007(2) C (3) 0.069(3) 0.038(2) (2) (2) (2) O (4) 0.151(4) 0.110(3) 0.075(3) (3) 0.032(3) C (5) 0.097(4) 0.073(3) 0.002(3) (3) 0.028(3) C (3) 0.083(3) 0.042(2) (2) 0.000(2) (2) O (3) 0.086(2) 0.059(2) (2) 0.018(2) (1) C (3) 0.073(3) 0.060(2) (2) 0.006(2) 0.004(2) C (6) 0.089(4) 0.109(4) 0.020(4) 0.038(4) 0.014(3) C (3) 0.070(3) 0.038(2) (2) (2) 0.005(2) C (3) 0.072(3) 0.038(2) (2) (2) 0.000(2) C (3) 0.083(3) 0.037(2) (2) (2) 0.003(2) C (3) 0.086(3) 0.040(2) (2) (2) 0.009(2) C (3) 0.086(3) 0.037(2) (2) 0.005(2) 0.001(2) C (3) 0.078(3) 0.034(2) (2) (2) (2) O (2) 0.118(3) 0.044(2) (2) 0.004(1) (1) C (3) 0.094(3) 0.058(2) (2) 0.005(2) (2) O (2) 0.103(2) 0.055(2) (2) 0.001(1) 0.003(1) C (3) 0.123(4) 0.077(3) 0.004(3) 0.007(2) 0.023(3)

10 110 Piperidine derivatives Table 4.4 (continued) Atom U 11 U 22 U 33 U 12 U 13 U 23 O (2) 0.107(2) 0.047(1) (1) (1) (1) C (4) 0.097(3) 0.058(3) (3) (2) (2) C (3) 0.078(3) 0.043(2) 0.002(2) (1) (2) C (3) 0.077(3) 0.047(2) 0.007(2) (2) (2) C (3) 0.063(3) 0.050(2) 0.001(2) (2) (2) C (3) 0.067(3) 0.046(2) (2) (2) (2) C (3) 0.081(3) 0.043(2) 0.001(2) (2) (2) C (3) 0.061(3) 0.050(2) (2) (2) (2) O (2) 0.080(2) 0.056(2) (1) (1) 0.004(1) C (4) 0.078(3) 0.074(3) 0.001(3) (2) 0.008(2) O (3) 0.084(2) 0.050(1) (2) (1) (1) C (4) 0.101(4) 0.078(3) (3) (3) 0.004(2) O (3) 0.066(2) 0.069(2) 0.001(2) (2) (1) C (5) 0.069(3) 0.081(3) 0.014(3) (3) 0.002(2)

11 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Table 4.5: Bond Lengths for (1) (Å). Atoms Length Atoms Length N1-C (5) C16-C (5) N1-C (4) C16-O (5) N1-C (4) C17-O (4) C2-C (5) C17-C (5) C2-C (5) O19-C (4) C3-C (6) O21-C (5) C4-O (5) O23-C (5) C4-C (6) C25-C (6) C5-C (6) C25-C (5) C5-C (5) C26-C (5) C6-C (5) C27-O (5) C9-O (4) C27-C (5) C9-C (5) C28-O (4) C11-C (6) C28-C (5) C13-C (5) C29-O (4) C13-C (5) C29-C (5) C14-C (5) O31-C (5) C15-O (4) O33-C (5) C15-C (5) O35-C (5)

12 112 Piperidine derivatives Table 4.6: Bond Angles for (1) ( ). Atoms Angle Atoms Angle C9-N1-C (3) C17-C16-C (4) C9-N1-C (3) C17-C16-O (3) C2-N1-C (3) C15-C16-O (3) N1-C2-C (3) O19-C17-C (3) N1-C2-C (3) O19-C17-C (4) C3-C2-C (3) C18-C17-C (4) C4-C3-C (4) C17-C18-C (3) O7-C4-C (5) C17-O19-C (3) O7-C4-C (5) C16-O21-C (3) C3-C4-C (4) C15-O23-C (3) C4-C5-C (4) C26-C25-C (3) C4-C5-C (4) C26-C25-C (4) C8-C5-C (4) C30-C25-C (4) N1-C6-C (3) C25-C26-C (4) N1-C6-C (3) O35-C27-C (4) C13-C6-C (3) O35-C27-C (3) O10-C9-N (4) C26-C27-C (4) O10-C9-C (4) O33-C28-C (3) N1-C9-C (3) O33-C28-C (4) C12-C11-C (4) C29-C28-C (4) C18-C13-C (4) O31-C29-C (3) C18-C13-C (3) O31-C29-C (4) C14-C13-C (3) C28-C29-C (4) C15-C14-C (3) C29-C30-C (4) O23-C15-C (3) C29-O31-C (3) O23-C15-C (4) C28-O33-C (3) C14-C15-C (3) C27-O35-C (3)

13 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Table 4.7: Torsion Angles for (1)( ). Atoms Angle Atoms Angle C9-N1-C6-C (5) C2-N1-C6-C (4) C9-N1-C6-C (4) C2-N1-C6-C5-3.1(5) N1-C6-C5-C4 46.3(5) C13-C6-C5-C (4) N1-C6-C5-C (4) C13-C6-C5-C7-61.1(5) C6-C5-C4-O (6) C7-C5-C4-O8 12.4(8) C6-C5-C4-C3-40.4(6) C7-C5-C4-C (5) O8-C4-C3-C (5) C5-C4-C3-C2-9.2(6) C9-N1-C2-C (4) C6-N1-C2-C3-44.8(5) C9-N1-C2-C (5) C6-N1-C2-C (4) C4-C3-C2-N1 50.4(5) C4-C3-C2-C (5) N1-C6-C13-C (5) C5-C6-C13-C (5) N1-C6-C13-C (4) C5-C6-C13-C (4) C14-C13-C18-C17-2.2(6) C6-C13-C18-C (4) C13-C18-C17-O (4) C13-C18-C17-C16 0.9(7) O19-C17-C16-O21-0.8(6) C18-C17-C16-O (4) O19-C17-C16-C (4) C18-C17-C16-C15 1.1(7) O21-C16-C15-O23 0.5(6) C17-C16-C15-O (4) O21-C16-C15-C (4) C17-C16-C15-C14-1.8(7) O23-C15-C14-C (4) C16-C15-C14-C13 0.5(6)

14 114 Piperidine derivatives Table 4.7 (continued) Atoms Angle Atoms Angle C18-C13-C14-C15 1.5(6) C6-C13-C14-C (4) C14-C15-O23-C24 5.1(6) C16-C15-O23-C (4) C17-C16-O21-C (5) C15-C16-O21-C (5) C18-C17-O19-C (7) C16-C17-O19-C (4) N1-C2-C25-C (5) C3-C2-C25-C26 3.3(6) N1-C2-C25-C (5) C3-C2-C25-C (4) C26-C25-C30-C29 0.8(7) C2-C25-C30-C (4) C25-C30-C29-O (4) C25-C30-C29-C28 0.2(7) O31-C29-C28-O33 3.7(6) C30-C29-C28-O (4) O31-C29-C28-C (4) C30-C29-C28-C27-1.7(7) O33-C28-C27-O35-3.8(7) C29-C28-C27-O (4) O33-C28-C27-C (4) 29-C28-C27-C26 2.2(7) C30-C25-C26-C27-0.3(7) C2-C25-C26-C (4) O35-C27-C26-C (4) C28-C27-C26-C25-1.2(7) C28-C27-O35-C (5) C26-C27-O35-C36 0.6(8) C29-C28-O33-C (5) C27-C28-O33-C (6) C28-C29-O31-C (4) C30-C29-O31-C (6) C2-N1-C9-O (6) C6-N1-C9-O (4) C2-N1-C9-C (4) C6-N1-C9-C11 6.9(6) C12-C11-C9-O (8) C12-C11-C9-N (6)

15 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Table 4.8: Hydrogen-bonding geometry for (1) (Å, ) D H...A D H H A D A D H...A C6 H6...O21 (i) (4) 165 C32 H32A...O23 (ii) (6) 178 C24 H24B...O10 (iii) (3) 156 C20 H20C...O31 (iv) (5) 150 Symmetry Codes (i) 1/2 + X,y,1/2 z (ii) /2 + x,1/2 y,1 z (iii) 1/2 + x,1/2 y,1 z (iv) x,1/2 y, 1/2 + z

16 116 Piperidine derivatives Figure 4.2: ORTEP of the molecule (1) with thermal ellipsoids drawn at 50% probability.

17 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Figure 4.3: Packing of the molecules (1) when viewed down the a axis. The dashed lines represent the hydrogen bond.

18 118 Piperidine derivatives Figure 4.4: Packing of the molecules (1) when viewed down the b axis. The dashed lines represent the hydrogen bond.

19 4.1 1-acryloyl-3-methyl-2,6-bis(3,4,5-trimethoxy Figure 4.5: Packing of the molecules (1) when viewed down the c axis. The dashed lines represent the hydrogen bond.

20 120 Piperidine derivatives acryloyl-2,6-bis(4-chlorophenyl)-3,5-dimethyl piperidine-4-one (2) Synthesis To a well stirred solution of 2,6-bis(4-chlorophenyl)-3,5-dimethylpiperidine- 4-one (5 mmol) and triethylamine (5 mmol) in 30 ml of benzene, 3-chloropro panoyl chloride (5 mmol) in 20 ml benzene was added drop wise through the addition funnel for about an hour. The resulting mixture was stirred for about 4 hours under room condition. After the completion of the reaction the mixture was quenched in cold water and the organic layer was extracted into ethyl acetate, washed with 5% sodium bicarbonate solution and dried over anhydrous sodium sulphate. This upon evaporation and recrystallisation in alcohol yielded 2,6-bis(4-chlorophenyl)-1-(3-chloropropanoyl)- 3,5-dimethylpiperidine-4-one. Further the crystals were dissolved in ethanol (60 ml), refluxed for half an hour and allowed to crystallize by slow evaporation. The schematic diagram of the molecule is shown in figure Crystal and molecular structure A white rectangular crystal of C 22 H 21 Cl 2 NO 2, with dimensions of mm was chosen for X-ray diffraction study. The procedures employed for data collection and data reduction are given in section 3.1. The structure was solved by direct methods using SHELXS-97. All the frames could be indexed using a primitive monoclinic lattice phase sets were refined with the best phase set having a CFOM of Using the normalised structure factors with these phases, a total of 1262 phases were generated. The final RE value turned out to be No absorption corrections were applied. All the non-hydrogen atoms were revealed in the first Fourier map itself. Full-matrix least squares refinement using SHELXL-97 with isotropic temperature factors for all the atoms converged the residual to R 1 = Refinement of the non-hydrogen atoms with anisotropic parameters was started at this stage. The hydrogen atoms were placed at chemically acceptable positions and were allowed to ride on the

21 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, O H 3 C CH 3 N Cl O Cl Figure 4.6: Schematic diagram parent atoms. 247 parameters were refined with 3542 unique reflections which saturated the residual to R 1 = The details of the crystal data and refinement are given in Table 4.9. The ORTEP of the molecule with thermal ellipsoids drawn at 50% probability is shown in figure 4.7. The final atomic coordinates and equivalent thermal parameters of the non-hydrogen and the hydrogen atoms are listed in Tables 4.10 and 4.11, respectively. Table 4.12 gives the anisotropic thermal parameters of the non-hydrogen atoms. Tables give the list of bond distances and bond angles of non-hydrogen atoms, respectively. Table 4.15 gives the list of torsion angles. The bond lengths and bond angles of all the non-hydrogen atoms are in good agreement with the standard values. The piperidine ring in the moiety is puckered. The ring-puckering analysis of six-membered ring in the molecule indicates that the ring adopts a boat conformation, with a puckering amplitude Q = 0.670(2)Å, θ=85.71(2) and φ=72.45(2). Atoms C2

22 122 Piperidine derivatives and C6 deviate from the plane (Cremer & Pople, 1975) defined by the atoms N1/C2/C3/C4/C5/C6 by (2)Å and 0.240(2)Å, respectively. The piperidine ring in the molecule 1-acryloyl-2,6-bis(4-chlorophenyl)-3,5- dimethylpiperidine-4-one has a weighted average torsion angle of The substituent at C2 is in equatorial conformation as indicated by the dihedral angle of 86.87(1) between piperidine ring and phenyl ring and the substituent at C6 between the piperidine and phenyl ring has dihedral angle of 77.81(1). The methyl groups substituted at C3 and C5 are oriented in -syn-clinal and +anti-periplanar conformation as indicated by the torsion angle value of -65.3(2) for N1 C2 C3 C7 and (18) for N1 C6 C5 C9, respectively. The torsion angle values of -3.0(3) for C6 N1 C17 O18 indicates that O18 is oriented in -syn-periplanar conformation. No classical hydrogen bonds are found. The packing of the molecules when viewed down the a, b and c axes are shown in figures 4.8, 4.9 and 4.10.

23 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, Table 4.9: Crystal data and structure refinement table for (2) Empirical formula C 22 H 21 Cl 2 NO 2 Formula weight Temperature 293(2)K Wavelength Å Crystal system Monoclinic Space group P2 1 /c Cell dimensions a = (8)Å b = (11)Å c = (9)Å β = (2) Volume (3)Å 3 Z 4 Density(calculated) Mg/m 3 Absorption coefficient mm 1 F Crystal size mm Theta range for data collection 3.00 to Index ranges 12 h k l 13 Reflections collected 6713 Independent reflections 3542 [R(int) = ] Absorption correction None Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 3542 / 0 / 247 Goodness-of-fit on F Final R indices [I > 2σ(I)] R1 = , wr2 = R indices (all data) R1 = , wr2 = Extinction coefficient (15) Largest diff. peak and hole and e.å 3

24 124 Piperidine derivatives Table 4.10: Atomic coordinates and equivalent thermal parameters of the nonhydrogen atoms for (2). Atom x y z U eq N (2) (8) (2) (4) C (2) (1) (2) (5) C (2) (1) (2) (5) C (2) (1) (2) (5) C (2) (1) (2) (5) C (2) (1) (2) (4) C (2) (1) (2) (7) O (2) (9) (2) (5) C (2) (1) (3) (7) C (2) (1) (2) (5) C (2) (1) (2) (5) C (2) (1) (2) (6) C (2) (1) (3) (6) C (3) (1) (3) (7) C (3) (1) (2) (6) Cl (1) (4) (9) (3) O (1) (8) (1) (4) C (2) (1) (2) (5) C (2) (1) (3) (7) C (3) (2) (3) (9) C (2) (1) (2) (5) C (2) (1) (2) (5) C (2) (1) (2) (6) C (3) (1) (2) (6) C (3) (1) (2) (6) C (2) (1) (2) (6) Cl (8) (4) (6) (3) U eq = (1/3) i U ij (a i a j )(a i.a j ) j

25 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, Table 4.11: Atomic coordinates and equivalent thermal parameters of the hydrogen atoms. Atom x y z U eq H H H H H7A H7B H7C H9A H9B H9C H H H H H H20A H20B H H H H

26 126 Piperidine derivatives Table 4.12: Anisotropic thermal parameters of the non-hydrogen atoms for (2). Atom U 11 U 22 U 33 U 12 U 13 U 23 N (9) (9) (9) (7) (7) (7) C (1) (1) (1) (8) (9) (9) C (1) (1) (1) (9) (1) (9) C (1) (1) (1) (9) (9) (9) C (1) (1) (1) (8) (9) (9) C (1) (1) (1) (8) (8) (8) C (1) (2) (1) (1) (1) (1) O (1) (1) (1) (8) (9) (9) C (1) (1) (2) (1) (1) (1) C (1) (1) (1) (8) (9) (9) C (1) (1) (1) (1) (1) (9) C (1) (1) (1) (1) (1) (1) C (1) (1) (2) (1) (1) (1) C (2) (1) (1) (1) (1) (1) C (1) (1) (1) (1) (1) (1) Cl (7) (4) (7) (4) (6) (4) O (9) (1) (1) (7) (7) (8) C (1) (1) (1) (9) (9) (1) C (1) (1) (2) (1) (1) (1) C (1) 0.136(3) (2) (2) (1) (2) C (1) (1) (1) (9) (1) (9) C (1) (1) (1) (1) (1) (1) C (1) (1) (1) (1) (1) (1) C (1) (1) (1) (1) (1) (1) C (2) (1) (1) (1) (1) (1) C (1) (1) (1) (1) (1) (1) Cl (6) (5) (4) (4) (4) (3)

27 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, Table 4.13: Bond Lengths for (2) (Å). Atoms Length Atoms Length N1-C (2) C12-C (3) N1-C (2) C13-C (3) N1-C (2) C13-Cl (2) C2-C (3) C14-C (3) C2-C (3) O18-C (3) C3-C (3) C17-C (3) C3-C (3) C19-C (3) C4-O (2) C21-C (3) C4-C (3) C21-C (3) C5-C (3) C22-C (3) C5-C (3) C23-C (3) C6-C (3) C24-C (3) C10-C (3) C24-Cl (2) C10-C (3) C25-C (3) C11-C (3)

28 128 Piperidine derivatives Table 4.14: Bond Angles for (2) ( ). Atoms Angle Atoms Angle C17-N1-C (2) C12-C11-C (2) C17-N1-C (2) C13-C12-C (2) C6-N1-C (1) C14-C13-C (2) N1-C2-C (2) C14-C13-Cl (2) N1-C2-C (2) C12-C13-Cl (2) C21-C2-C (2) C13-C14-C (2) C4-C3-C (2) C10-C15-C (2) C4-C3-C (2) O18-C17-N (2) C2-C3-C (2) O18-C17-C (2) O8-C4-C (2) N1-C17-C (2) O8-C4-C (2) C20-C19-C (3) C3-C4-C (2) C22-C21-C (2) C4-C5-C (2) C22-C21-C (2) C4-C5-C (2) C26-C21-C (2) C9-C5-C (2) C21-C22-C (2) N1-C6-C (1) C24-C23-C (2) N1-C6-C (1) C23-C24-C (2) C10-C6-C (1) C23-C24-Cl (2) C15-C10-C (2) C25-C24-Cl (2) C15-C10-C (2) C24-C25-C (2) C11-C10-C (2) C25-C26-C (2)

29 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, Table 4.15: Torsion Angles for (2)( ). Atoms Angle Atoms Angle C17-N1-C2-C (2) C6-N(-C2-C (2) C17-N1-C2-C (2) C6-N1-C2-C3-46.8(2) N1-C2-C3-C4 56.9(2) C21-C2-C3-C4-71.3(2) N1-C2-C3-C7-65.3(2) C21-C2-C3-C (2) C2-C3-C4-O (2) C7-C3-C4-O8-72.4(3) C2-C3-C4-C5-16.2(2) C7-C3-C4-C (2) O8-C4-C5-C9 18.2(3) C3-C4-C5-C (2) O8-C4-C5-C (2) C3-C4-C5-C6-35.4(2) C17-N1-C6-C (2) C2-N1-C6-C (2) C17-N1-C6-C (2) C2-N1-C6-C5-4.6(2) C4-C5-C6-N1 46.3(2) C9-C5-C6-N (2) C4-C5-C6-C (2) C9-C5-C6-C (2) N1-C6-C10-C (2) C5-C6-C10-C (2) N1-C6-C10-C (2) C5-C6-C10-C (2) C15-C10-C11-C12-1.3(3) C6-C10-C11-C (2) C10-C11-C12-C13 0.5(3) C11-C12-C13-C14 0.5(4) C11-C12-C13-Cl (2) C12-C13-C14-C15-0.7(4) Cl16-C13-C14-C (2) C11-C10-C15-C14 1.0(3) C6-C10-C15-C (2) C13-C14-C15-C10 0.0(4) C6-N1-C17-O18-3.0(3) C2-N1-C17-O (2) C6-N1-C17-C (2) C2-N1-C17-C (3) O18-C17-C19-C20 1.7(4) N1-C17-C19-C (2) N1-C2-C21-C (2) C3-C2-C21-C22-3.5(3) N1-C2-C21-C (2) C3-C2-C21-C (2) C26-C21-C22-C23-0.7(3) C2-C21-C22-C (2) C21-C22-C23-C24 0.0(3) C22-C23-C24-C25 0.7(3) C22-C23-C24-Cl (2) C23-C24-C25-C26-0.8(4) Cl27-C24-C25-C (2) C24-C25-C26-C21 0.2(4) C22-C21-C26-C25 0.6(3) C2-C21-C26-C (2)

30 130 Piperidine derivatives Figure 4.7: ORTEP of the molecule (2) with thermal ellipsoids drawn at 50% probability.

31 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, Figure 4.8: Packing of the molecules (2) when viewed down the a axis.

32 132 Piperidine derivatives Figure 4.9: Packing of the molecules (2) when viewed down the b axis.

33 4.2 1-acryloyl-2,6-bis(4-chlorophenyl)-3, Figure 4.10: Packing of the molecules (2) when viewed down the c axis.

34 134 Piperidine derivatives (2-chloroacetyl)-3-methyl-2,6-bis (3,4,5-tri methoxyphenyl)piperidine-4-one(3) Synthesis To a well stirred solution of 3-methyl-2,6-bis(3,4,5-trimethoxyphenyl)piperi dine-4-one (5 mmol) and triethylamine (5 mmol) in 30 ml of benzene, chloroacetyl chloride (5 mmol) in 20 ml benzene was added drop wise through the addition funnel for about an hour. The resulting mixture was stirred for about 4 hours under room condition. After the completion of the reaction the mixture was quenched in cold water and the organic layer was extracted into ethyl acetate, washed with 5% sodium bicarbonate solution and dried over anhydrous sodium sulphate. This upon evaporation and recrystallisation yielded 1-(2-chloroacetyl)-3-methyl-2,6-bis(3, 4,5-trimethoxyphenyl) piperidine-4-one. The schematic diagram of the molecule is shown in figure O CH 3 H 3 C O N O CH 3 H 3 C O O O CH 3 H 3 C O Cl O CH 3 Figure 4.11: Schematic diagram

35 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Crystal and molecular structure A white rectangular crystal of C 26 H 32 ClNO 8, with dimensions of mm was chosen for X-ray diffraction study. The procedures employed for data collection and data reduction are given in section 3.1. The structure was solved by direct methods using SHELXS-97. All the frames could be indexed using a primitive orthorhombic lattice phase sets were refined with the best phase set having a CFOM of Using the normalised structure factors with these phases, a total of 1212 phases were generated. The final RE value turned out to be No absorption corrections were applied. All the non-hydrogen atoms were revealed in the first Fourier map itself. Full-matrix least squares refinement using SHELXL-97 with isotropic temperature factors for all the atoms converged the residual to R 1 = Refinement of the non-hydrogen atoms with anisotropic parameters was started at this stage. The hydrogen atoms were placed at chemically acceptable positions and were allowed to ride on the parent atoms. 332 parameters were refined with 4464 unique reflections which saturated the residual to R 1 = The details of the crystal data and refinement are given in Table The ORTEP of the molecule with thermal ellipsoids drawn at 50% probability is shown in figure The final atomic coordinates and equivalent thermal parameters of the non-hydrogen and the hydrogen atoms are listed in Tables 4.17 and 4.18, respectively. Table 4.19 gives the anisotropic thermal parameters of the non-hydrogen atoms. Tables give the list of bond distances and bond angles of non-hydrogen atoms, respectively. Table 4.22 gives the list of torsion angles. The bond lengths and bond angles of all the non-hydrogen atoms are in good agreement with the standard values. The ring-puckering analysis (Cremer and Pople, 1975) of six-membered ring in the molecule indicates that the ring adopts a twist boat conformation, with a puckering amplitude Q = 0.655(4)Å, θ=93.1(1) and φ=254.4(3). Atoms C2 and C6 deviate from the plane (Cremer and Pople, 1975) defined by the atoms N1/C2/C3/C4/C5/C6 by 0.380(3)Å and (3)Å, respectively. The substituent at C2 is in equatorial conformation as indicated by the dihedral angle of 85.18(2) between piperidine and phenyl ring and the sub-

36 136 Piperidine derivatives stituent at C6 has a dihedral angle of 73.52(2) between the piperidine ring and phenyl ring. The piperidine ring has a weighted average torsion angle value of The torsion angle value of for N1 C6 C5 C8 indicates that methyl group substituted at C5 is oriented in -anti-periplanar conformation. The torsion angle value of 180.0(3) for C6 N1 C9 O10 indicates that O10 is oriented in +anti-periplanar conformation. The methoxy groups substituted at C27, C29, C17 and C15 are nearly planar with the phenyl ring whereas the methoxy group substituted at C28 and C16 are nearly orthogonal as indicated by the torsion angles (Table 4.22). The molecules are linked into infinite double helices which in turn are linked to one another by the intermolecular hydrogen bonds of the type C H O as shown in table The packing of the molecules when viewed down the a, b and c axes are shown in figures 4.13, 4.14 and 4.15.

37 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.16: Crystal data and structure refinement table for (3) Empirical formula C 26 H 32 ClNO 8 Formula weight Temperature 293(2)K Wavelength Å Crystal system Orthorhombic Space group Pbca Cell dimensions a = (8)Å b = (11)Å c = (16)Å Volume (6)Å 3 Z 8 Density(calculated) Mg/m 3 Absorption coefficient mm 1 F Crystal size mm Theta range for data collection to Index ranges 16 h k l 27 Reflections collected 8214 Independent reflections 4464 [R(int) = ] Absorption correction None Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 4464 / 0 / 332 Goodness-of-fit on F Final R indices [I > 2σ(I)] R1 = , wr2 = R indices (all data) R1 = , wr2 = Largest diff. peak and hole and e.å 3

38 138 Piperidine derivatives Table 4.17: Atomic coordinates and equivalent thermal parameters of the nonhydrogen atoms for (3). Atom x y z U eq N (2) (1) (1) (6) C (2) (2) (1) (8) C (3) (2) (2) (1) C (3) (2) (2) (1) C (3) (2) (1) (9) C (2) (2) (1) (7) O (3) (3) (2) (2) C (4) (3) (2) (1) C (2) (2) (1) (8) O (2) (2) (1) (7) C (3) (2) (2) (9) Cl (9) (6) (6) (4) C (2) (2) (1) (7) C (2) (2) (1) (7) C (2) (2) (1) (7) C (2) (2) (1) (7) C (2) (2) (1) (7) C (2) (2) (1) (7) O (1) (1) (9) (6) C (3) (2) (1) (9) O (1) (1) (9) (6) C (2) (2) (2) (1)

39 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.17 (continued) Atom x y z U eq O (1) (1) (9) (6) C (3) (2) (1) (9) C (2) (2) (1) (7) C (2) (2) (1) (8) C (3) (2) (1) (8) C (2) (2) (1) (8) C (2) (2) (1) (7) C (2) (2) (1) (7) O (2) (1) (9) (6) C (3) (2) (2) (1) O (2) (1) (9) (7) C (3) (3) (2) (1) O (2) (1) (1) (8) C (4) (2) (2) (1) U eq = (1/3) i U ij (a i a j )(a i.a j ) j

40 140 Piperidine derivatives Table 4.18: Atomic coordinates and equivalent thermal parameters of the hydrogen atoms for (3). Atom x y z U eq H H3A H3B H H H8A H8B H8C H11A H11B H H H20A H20B H20C H22A

41 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.18 (continued) Atom x y z U eq H22B H22C H24A H24B H24C H H H32A H32B H32C H34A H34B H34C H36A H36B H36C

42 142 Piperidine derivatives Table 4.19: Anisotropic thermal parameters of the non-hydrogen atoms for (3). Atom U 11 U 22 U 33 U 12 U 13 U 23 N (1) (1) (1) (1) (1) (1) C (2) (2) (2) (1) (1) (1) C (2) (3) (2) (2) (2) (2) C (3) (3) (2) (2) (2) (2) C (2) (2) (2) (2) (2) (1) C (2) (2) (1) (1) (1) (1) O (3) (4) (3) (3) (3) (3) C (4) (3) (3) (3) (3) (2) C (2) (2) (2) (1) (1) (1) O (2) (2) (1) (1) (1) (1) C (2) (2) (2) (1) (2) (2) Cl (9) (6) (1) (6) (8) (6) C (1) (2) (1) (1) (1) (1) C (2) (2) (1) (1) (1) (1) C (2) (2) (1) (1) (1) (1) C (2) (2) (2) (1) (1) (1) C (2) (2) (1) (1) (1) (1) C (2) (2) (2) (1) (1) (1) O (1) (2) (1) (1) (1) (1) C (2) (2) (2) (2) (2) (2) O (1) (2) (1) (1) (1) (1)

43 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.19 (continued) Atom U 11 U 22 U 33 U 12 U 13 U 23 C (2) (3) (2) (2) (2) (2) O (1) (2) (1) (1) (1) (1) C (2) (2) (2) (2) (2) (2) C (2) (2) (2) (1) (1) (1) C (2) (2) (2) (2) (2) (1) C (2) (2) (2) (2) (2) (1) C (2) (2) (1) (2) (1) (1) C (2) (2) (2) (1) (1) (1) C (2) (2) (2) (1) (1) (1) O (1) (1) (1) (1) (1) (1) C (2) (2) (2) (2) (2) (2) O (2) (2) (1) (1) (1) (1) C (3) (3) (3) (2) (2) (2) O (2) (2) (2) (1) (2) (1) C (4) (2) (3) (3) (3) (2)

44 144 Piperidine derivatives Table 4.20: Bond Lengths for (3) (Å). Atoms Length Atoms Length N1-C (4) C16-C (4) N1-C (4) C16-O (3) N1-C (4) C17-O (3) C2-C (5) C17-C (4) C2-C (4) O19-C (4) C3-C (5) O21-C (4) C4-O (4) O23-C (4) C4-C (5) C25-C (5) C5-C (5) C25-C (4) C5-C (4) C26-C (4) C6-C (4) C27-O (4) C9-O (4) C27-C (4) C9-C (5) C28-O (3) C11-Cl (3) C28-C (5) C13-C (4) C29-O (4) C13-C (4) C29-C (4) C14-C (4) O31-C (4) C15-O (4) O33-C (4) C15-C (4) O35-C (5)

45 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.20 (continued) Atoms Length Atoms Length C2-H C22-H22B C3-H3A C22-H22C C3-H3B C24-H24A C5-H C24-H24B C6-H C24-H24C C8-H8A C26-H C8-H8B C30-H C8-H8C C32-H32A C11-H11A C32-H32B C11-H11B C32-H32C C14-H C34-H34A C18-H C34-H34B C20-H20A C34-H34C C20-H20B C36-H36A C20-H20C C36-H36B C22-H22A C36-H36C

46 146 Piperidine derivatives Table 4.21: Bond Angles for (3) ( ). Atoms Angle Atoms Angle C9-N1-C (3) C17-C16-O (3) C9-N1-C (2) C17-C16-C (3) C2-N1-C (2) O21-C16-C (3) N1-C2-C (2) O19-C17-C (3) N1-C2-C (2) O19-C17-C (3) C3-C2-C (3) C18-C17-C (3) C4-C3-C (3) C17-C18-C (3) O7-C4-C (4) C17-O19-C (2) O7-C4-C (4) C16-O21-C (2) C3-C4-C (3) C15-O23-C (2) C8-C5-C (3) C26-C25-C (3) C8-C5-C (3) C26-C25-C (3) C4-C5-C (3) C30-C25-C (3) N1-C6-C (2) C25-C26-C (3) N1-C6-C (2) O35-C27-C (3) C13-C6-C (2) O35-C27-C (3) O10-C9-N (3) C28-C27-C (3) O10-C9-C (3) O33-C28-C (3) N1-C9-C (3) O33-C28-C (3) C9-C11-Cl (2) C29-C28-C (3) C14-C13-C (3) O31-C29-C (3) C14-C13-C (2) O31-C29-C (3) C18-C13-C (3) C28-C29-C (3) C13-C14-C (3) C29-C30-C (3) O23-C15-C (3) C29-O31-C (2) O23-C15-C (2) C28-O33-C (3) C14-C15-C (3) C27-O35-C (3) N1-C2-H O21-C22-H22A C3-C2-H O21-C22-H22B C25-C2-H H22A-C22-H22B C4-C3-H3A O21-C22-H22C 109.5

47 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.21 (continued) Atoms Angle Atoms Angle C2-C3-H3A H22A-C22-H22C C4-C3-H3B H22B-C22-H22C C2-C3-H3B O23-C24-H24A H3A-C3-H3B O23-C24-H24B C8-C5-H H24A-C24-H24B C4-C5-H O23-C24-H24C C6-C5-H H24A-C24-H24C N1-C6-H H24B-C24-H24C C13-C6-H C25-C26-H C5-C6-H C27-C26-H C5-C8-H8A C29-C30-H C5-C8-H8B C25-C30-H H8A-C8-H8B O31-C32-H32A C5-C8-H8C O31-C32-H32B H8A-C8-H8C H32A-C32-H32B H8B-C8-H8C O31-C32-H32C C9-C11-H11A H32A-C32-H32C Cl12-C11-H11A H32B-C32-H32C C9-C11-H11B O33-C34-H34A Cl12-C11-H11B O33-C34-H34B H11A-C11-H11B H34A-C34-H34B C13-C14-H O33-C34-H34C C15-C14-H H34A-C34-H34C C17-C18-H H34B-C34-H34C C13-C18-H O35-C36-H36A O19-C20-H20A O35-C36-H36B O19-C20-H20B H36A-C36-H36B H20A-C20-H20B O35-C36-H36C O19-C20-H20C H36A-C36-H36C H20A-C20-H20C H36B-C36-H36C H20B-C20-H20C 109.5

48 148 Piperidine derivatives Table 4.22: Torsion Angles for (3)( ). Atoms Angle Atoms Angle C9-N1-C2-C (3) C6-N1-C2-C3-42.4(3) C9-N1-C2-C (3) C6-N1-C2-C (3) N1-C2-C3-C4 55.7(4) C25-C2-C3-C4-72.3(4) C2-C3-C4-O (4) C2-C3-C4-C5-17.8(5) O7-C4-C5-C8 21.9(6) C3-C4-C5-C (4) O7-C4-C5-C (4) C3-C4-C5-C6-34.0(4) C9-N1-C6-C (3) C2-N1-C6-C (3) C9-N1-C6-C (3) C2-N1-C6-C5-7.8(3) C8-C5-C6-N (3) C4-C5-C6-N1 46.9(3) C8-C5-C6-C (4) C4-C5-C6-C (3) C2-N1-C9-O (4) C6-N1-C9-O (3) C2-N1-C9-C (3) C6-N1-C9-C11 0.7(4) O10-C9-C11-Cl12-4.3(4) N1-C9-C11-Cl (2) N1-C6-C13-C (3) C5-C6-C13-C (3) N1-C6-C13-C (4) C5-C6-C13-C (3) C18-C13-C14-C15-2.3(4) C6-C13-C14-C (3) C13-C14-C15-O (3) C13-C14-C15-C16 1.7(4) O23-C15-C16-C (3) C14-C15-C16-C17 0.2(4) O23-C15-C16-O21-0.5(4) C14-C15-C16-O (3) O21-C16-C17-O19 1.4(4) C15-C16-C17-O (3) O21-C16-C17-C (3) C15-C16-C17-C18-1.7(4)

49 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Table 4.22 (continued) Atoms Angle Atoms Angle O19-C17-C18-C (3) C16-C17-C18-C13 1.2(4) C14-C13-C18-C17 0.8(4) C6-C13-C18-C (3) C18-C17-O19-C20 5.8(4) C16-C17-O19-C (3) C17-C16-O21-C (4) C15-C16-O21-C (4) C14-C15-O23-C (4) C16-C15-O23-C (3) N1-C2-C25-C (3) C3-C2-C25-C26-1.1(4) N1-C2-C25-C (4) C3-C2-C25-C (3) C30-C25-C26-C27-1.1(5) C2-C25-C26-C (3) C25-C26-C27-O (3) C25-C26-C27-C28-0.4(5) O35-C27-C28-O33-1.6(5) C26-C27-C28-O (3) O35-C27-C28-C (3) C26-C27-C28-C29 1.5(5) O33-C28-C29-O31 1.8(4) C27-C28-C29-O (3) O33-C28-C29-C (3) C27-C28-C29-C30-1.2(5) O31-C29-C30-C (3) C28-C29-C30-C25-0.3(4) C26-C25-C30-C29 1.5(4) C2-C25-C30-C (3) C28-C29-O31-C (3) C30-C29-O31-C (4) C29-C28-O33-C (4) C27-C28-O33-C (4) C28-C27-O35-C (4) C26-C27-O35-C36-0.2(6) Table 4.23: Hydrogen-bonding geometry for (3) (Å, ) D H...A D H H A D A D H...A C6 H6...O21 (i) (4) 170 C20 H20...O31 (ii) (4) 155 C24 H24B...O10 (iii) (3) 154 Symmetry Codes (i) 1/2 + X,y,1/2 z (ii) x, 1/2 y, 1/2 + z (iii) 1/2 + x, 1/2 y,1 z

50 150 Piperidine derivatives Figure 4.12: ORTEP of the molecule (3) with thermal ellipsoids drawn at 50% probability.

51 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Figure 4.13: Packing of the molecules (3) when viewed down the a axis. The dashed lines represent the hydrogen bond.

52 152 Piperidine derivatives Figure 4.14: Packing of the molecules (3) when viewed down the b axis. The dashed lines represent the hydrogen bond.

53 4.3 1-(2-chloroacetyl)-3-methyl-2,6-bis(3,4, Figure 4.15: Packing of the molecules (3) when viewed down the c axis. The dashed lines represent the hydrogen bond.

54 154 Piperidine derivatives acryloyl-2,6-bis(4-methylphenyl)-3,5-dimeth ylpiperidine-4-one, 0.5(C 2 H 4 O 2 ) (4) Synthesis To a well stirred solution of 2,6-bis(4-methylphenyl)-3,5-dimethyl piperidine- 4-one (5 mmol) and triethylamine (5 mmol) in 30 ml of benzene, 3-chloropro panoyl chloride (5 mmol) in 20 ml benzene was added dropwise through the addition funnel for about an hour. The resulting mixture was stirred for about 4 hours under room condition. After the completion of the reaction the mixture was quenched in cold water and the organic layer was extracted into ethyl acetate, washed with 5% sodium bicarbonate solution and dried over anhydrous sodium sulphate. This upon evaporation and recrystallisation in alcohol yielded 2,6-bis(4-methyl)-1-(3-chloropropan oyl)-3,5-dimethyl piperidin-4-one. Further the crystals were dissolved in ethanol (60 ml), refluxed for half an hour and allowed to crystallize by slow evaporation. The schematic diagram of the molecule is shown in figure 4.16 O CH 3 N H 3 C O CH 3 CH 2 Figure 4.16: Schematic diagram

55 4.4 1-acryloyl-2,6-bis(4-methylphenyl)-3, Crystal and molecular structure A white rectangular crystal of C 24 H 27 NO 3, with dimensions of mm was chosen for X-ray diffraction study. The procedures employed for data collection and data reduction are given in section 3.1. The structure was solved by direct methods using SHELXS-97. All the frames could be indexed using a primitive monoclinic lattice phase sets were refined with the best phase set having a CFOM of Using the normalised structure factors with these phases, a total of 1193 phases were generated. The final RE value turned out to be No absorption corrections were applied. All the non-hydrogen atoms were revealed in the first Fourier map itself. Full-matrix least squares refinement using SHELXL-97 with isotropic temperature factors for all the atoms converged the residual to R 1 = Refinement of the non-hydrogen atoms with anisotropic parameters was started at this stage. The hydrogen atoms were placed at chemically acceptable positions and were allowed to ride on the parent atoms. 257 parameters were refined with 3536 unique reflections which saturated the residual to R 1 = The details of the crystal data and refinement are given in Table The final atomic coordinates and equivalent thermal parameters of the non-hydrogen and the hydrogen atoms are listed in Tables 4.25 and 4.26, respectively. Table 4.27 gives the anisotropic thermal parameters of the non-hydrogen atoms. Tables give the list of bond distances, bond angles of non-hydrogen atoms respectively. Table 4.30 gives the list of torsion angles. The bond lengths and bond angles of all the non-hydrogen atoms are in good agreement with the standard values. The ORTEP of the molecule with thermal ellipsoids drawn at 50% probability is shown in Figure The piperidine ring adopts a twist boat conformation with the atoms N1 and C6 deviating by 0.396(3)Å and (3)Å from the plane (Cremer and Pople, 1975) defined by the atoms N1/C2/C3/C4/C5/C6. The ringpuckering paramters are given by Q = 0.692(3)Å, θ = 92.5(2) and φ = 256.0(3), respectively. The substituent at C2 is in equatorial conformation as indicated by the dihedral angle of 85.62(2) between piperidine and

56 156 Piperidine derivatives phenyl ring and the substituent at C6 has a dihedral angle of 68.36(2) betw een the piperidine ring and phenyl ring. The piperidine ring in the molecule has a weighted average torsion angle of The torsion angle value of for N1 C6 C5 C8 indicates that methyl group substituted at C5 is oriented in -anti-periplanar conformation. The torsion angle value of for N1-C6-C9-O10 indicates that O10 is oriented in +antiperiplanar conformation. The acryloyl group substituted at N1 is oriented in +anti-periplanr conformation as indicated by the torsion angle value of for C2-N1-O9-C11. No classical hydrogen bonds are observed. The packing of the molecules when viewed down the a, b and c axes are shown in figures 4.18, 4.19 and 4.20.