SUPPLEMENTARY MATERIAL
Stereochemical effect on biological activities of new series of piperidin4-one derivatives
Venkatesan Periyasamya* and Maruthavanan Thiyagarajanb
a*
Department of Chemistry, Mahendra Institute of Technology, Namakkal-637 503,
India; bDepartment of Chemistry, Sona College of Technology, Salem-636 005, India
*Corresponding author. Email: venkatesanps@yahoo.co.in
New series of (2S,3R,4S,6R)-3-methyl-4-alkyl-2,6-diarylpiperidin-4-ol were
synthesized by the reduction of cis-3-alkyl-2,6-diarylpiperidin-4-one using
Grignard reagent. The structural assignments and conformational studies of the
synthesized compounds were established based on the IR, 1H-NMR, 13C-NMR,
NOESY and mass spectral studies. Their stereochemical effect on antibacterial,
antifungal and anthelmintic activities was studied.
Keywords: piperidin-4-one; Grignard reagent; Mannich reaction; stereochemical
effect; biological activity
1. Experimental
1.1: General
All the common chemicals and solvents were purchased from Nice and Spectra
Chemicals, and the Grignard reagents were obtained from Sigma-Aldrich chemicals,
India. IR spectra were recorded on Perkin-Elmer 577 IR spectrophotometer using KBr
pellets in the range 4000 to 400 cm-1 and given in wave number (cm-1) scale. 1H-NMR
spectra (500 MHz) and 13C-NMR spectra (125 MHz) were recorded on Bruker
AVANCE III 500 MHz NMR Spectrometer in CDCl3 with tetramethyl silane as the
internal standard and the chemical shifts were reported in ppm scale. The 13C-NMR
spectra (75 MHz) were recorded on Bruker DSX 300 MHz NMR Spectrometer. Mass
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spectra were studied using JEOL GCMATE II mass spectrometer and fragmentations
were given in m/z values. The elemental analysis was done on Vario EL-III elemental
analyzer and analyzed reports were within  0.4% of the theoretical values. The purity
of the compounds was checked by thin layer chromatography on silica gel 60 F254
(Merck) and spots were developed using iodine vapour or ultraviolet light. The silica
gel 60-120 mesh (Merck) is used for column chromatography.
1.2: General procedure of synthesis of 3-methyl-4-alkyl-2,6-diarylpiperidin-4-ol
(6-15)
The appropriate cis-2,6-diarylpiperidin-4-ones (1-5) (0.005 mol) was dissolved in
sodium dried ether and ethyl magnesium bromide/isopropyl magnesium bromide
reagent (0.01 mol) was added slowly. The mixture was refluxed until the completion of
reaction. Then, it was allowed to cool and poured into the mixture of crushed ice (125
g), 100 mL of water and 10-20 ml of Conc. HCl contained in a 500 mL beaker. The
hydrochloride thus obtained was filtered and dried at the pump. The dried hydrochloride
was pasted with 2 or 3 drops of acetone and neutralized with aqueous ammonia
followed by the addition of water. The tertiary alcohols obtained were column
chromatographed from benzene-chloroform (3:1) eluent.
1.2.1: (2S,3R,4S,6R)-3-methyl-4-ethyl-2,6-diphenylpiperidin-4-ol (6)
Dull white viscous oil; Rf Value: 0.75 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3385 (merged, -NH and -OH), 2989 (ArCH); 1H NMR (500 MHz, CDCl3):  7.24-7.57
(m, 10H, ArH), 4.24 (dd, 3J6a,5a=13.0 Hz, 3J6a,5e=3.5 Hz, 1H, 6-Ha), 3.86 (d, 3J2a,3a=10.0
Hz, 1H, 2-Ha), 1.55 (m, 3J2a,3a=10.0 Hz, 1H, 3-Ha), 1.58-1.64 (m, 2J5a,5e=13.5 Hz, 2H, 5Ha and 5-He), 1.80-1.82 (br, 2H, NH and OH), 1.04 (m, 2H, 4-CH2CH3), 0.91 (t, 3H, 4CH2CH3), 0.91 (d, 3H, 3-CH3); 13C NMR (125 MHz, CDCl3):  64.0 (C-2), 47.9 (C-3),
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73.6 (C-4), 42.2 (C-5), 55.2 (C-6), 33.8 (4-CH2CH3), 7.9 (4-CH2CH3), 10.0 (3-CH3);
MS: m/z 295.56 (M+); Anal. Calcd. for C20H25NO: C, 81.31; H, 8.53; N, 4.74. Found:
C, 81.33; H, 8.51; N, 4.77.
1.2.2: (2S,3R,4S,6R)-3-methyl-4-ethyl-2,6-di(furan-2-yl)-piperidin-4-ol (7)
Pale yellow viscous oil; Rf Value: 0.48 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3305 (-NH), 3412 (broad, -OH), 3118 (ArCH); 1H NMR (500 MHz, CDCl3):  7.287.36; 6.19-6.31 (m, 6H, ArH), 4.36 (dd, 3J6a,5a=11.5 Hz, 3J6a,5e=3.0 Hz, 1H, 6-Ha), 4.03
(d, 3J2a,3a=10.5 Hz, 1H, 2-Ha), 1.99 (m, 3J2a,3a=10.5 Hz, 1H, 3-Ha), 1.94 (m, 2J5a,5e=13.5
Hz, 1H, 5-Ha), 1.89 (m, 2J5a,5e=13.5 Hz, 1H, 5-He), 1.72 (br, 2H, NH and OH), 1.64 (m,
2H, 4-CH2CH3), 1.24 (t, 3H, 4-CH2CH3), 0.72 (d, 3H, 3-CH3); 13C NMR (75 MHz,
CDCl3):  56.4 (C-2), 49.9 (C-3), 72.9 (C-4), 40.0 (C-5), 53.8 (C-6), 33.8 (4-CH2CH3),
8.0 (4-CH2CH3), 9.9 (3-CH3); MS: m/z 275.15 (M+); Anal. Calcd. for C16H21NO3: C,
69.79; H, 7.69; N, 5.09. Found: C, 69.78; H, 7.70; N, 5.07.
1.2.3: (2S,3R,4S,6R)-3-methyl-4-ethyl-2,6-di(4-chlorophenyl)piperidin-4-ol (8)
Pale yellow viscous oil; Rf Value: 0.54 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3303 (-NH), 3593 (broad, -OH), 3050 (ArCH); 1H NMR (500 MHz, CDCl3):  7.287.32 (m, 8H, ArH), 4.23 (dd, 3J6a,5a=11.3 Hz, 3J6a,5e=2.8 Hz, 1H, 6-Ha), 3.84 (d,
3
J2a,3a=10.5 Hz, 1H, 2-Ha), 1.67-1.72 (m, 2H, 3-Ha and 5-Ha), 1.77 (m, 2J5a,5e=13.7 Hz,
1H, 5-He), 1.67 (br, 2H, NH and OH), 1.60 (m, 2H, 4-CH2CH3), 0.92 (t, 3H, 4CH2CH3), 0.65 (d, 3H, 3-CH3); 13C NMR (125 MHz, CDCl3):  63.1 (C-2), 44.8 (C-3),
73.4 (C-4), 42.9 (C-5), 55.1 (C-6), 33.8 (4-CH2CH3), 7.9 (4-CH2CH3), 9.8 (3-CH3); MS:
m/z 364.01 (M+); Anal. Calcd. for C20H23Cl2NO: C, 65.94; H, 6.36; N, 3.84. Found: C,
65.92; H, 6.37; N, 3.84.
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1.2.4: (2S,3R,4S,6R)-3-methyl-4-ethyl-2,6-di(4-methoxyphenyl)piperidin-4-ol (9)
Pale yellow viscous oil; Rf Value: 0.78 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3304 (-NH), 3394 (broad, -OH), 3049 (ArCH); 1H NMR (500 MHz, CDCl3):  7.087.13 (m, 8H, ArH), 4.06 (dd, 3J6a,5a=12.5 Hz, 3J6a,5e=2.0 Hz, 1H, 6-Ha), 3.60 (d,
3
J2a,3a=10.0 Hz, 1H, 2-Ha), 3.84, 3.82 (s, 6H, Ar-OCH3), 2.68 (m, 3J2a,3a=10.0 Hz, 1H, 3-
Ha), 2.74 (m, 2J5a,5e=13.0 Hz, 1H, 5-Ha), 2.62 (m, 2J5a,5e=13.0 Hz, 1H, 5-He), 1.88 (br,
2H, NH and OH), 1.47 (m, 2H, 4-CH2CH3), 1.09 (t, 3H, 4-CH2CH3), 0.87 (d, 3H, 3CH3); 13C NMR (125 MHz, CDCl3):  67.9 (C-2), 51.8 (C-3), 74.1 (C-4), 43.8 (C-5),
61.0 (C-6), 34.2 (4-CH2CH3), 7.9 (4-CH2CH3), 10.2 (3-CH3), 55.3 (OCH3); MS: m/z
355.80 (M+); Anal. Calcd. for C22H29NO3: C, 74.33; H, 8.22; N, 3.94. Found: C, 74.32;
H, 8.20; N, 3.95.
1.2.5: (2S,3R,4S,6R)-3-methyl-4-ethyl-2,6-di(4-methylphenyl)piperidin-4-ol (10)
Pale yellow viscous oil; Rf Value: 0.76 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3280 (-NH), 3391 (broad, -OH), 3026 (ArCH); 1H NMR (500 MHz, CDCl3):  7.107.23 (m, 8H, ArH), 4.04 (dd, 3J6a,5a=12.5 Hz, 3J6a,5e=2.0 Hz, 1H, 6-Ha), 3.58 (d,
3
J2a,3a=10.0 Hz, 1H, 2-Ha), 2.29 (m, 3J2a,3a=10.0 Hz, 1H, 3-Ha), 2.40 (m, 2J5a,5e=13.0 Hz,
1H, 5-Ha), 2.33 (m, 2J5a,5e=13.0 Hz, 1H, 5-He), 2.23; 2.24 (t, 6H, Ar-CH3), 1.71-1.72 (br,
2H, NH and OH), 1.01 (m, 2H, 4-CH2CH3), 1.31 (t, 3H, 4-CH2CH3), 0.68 (d, 3H, 3CH3); 13C NMR (75 MHz, CDCl3):  65.2 (C-2), 49.8 (C-3), 74.0 (C-4), 42.8 (C-5),
58.2 (C-6), 33.9 (4-CH2CH3), 7.9 (4-CH2CH3), 21.2 (CH3); MS: m/z 323.10 (M+); Anal.
Calcd. for C22H29NO: C, 81.69; H, 9.04; N, 4.33. Found: C, 81.68; H, 9.06; N, 4.34.
1.2.6: (2S,3R,4S,6R)-3-methyl-4-(propan-2-yl)-2,6-diphenylpiperidin-4-ol (11)
Orange yellow viscous oil; Rf Value: 0.57 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
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3311 (-NH), 3410 (Broad, -OH), 3068 (ArCH); 1H NMR (500 MHz, CDCl3):  7.437.50 and 7.24-7.34 (m, 8H, ArH), 4.27 (dd, 3J6a,5a=11.5 Hz, 3J6a,5e=3.0 Hz, 1H, 6-Ha),
3.91 (d, 3J2a,3a=10.0 Hz, 1H, 2-Ha), 1.80 (dd, 2J5a,5e=12, 1H, 5-He), 1.75 (m, 1H, 5-Ha),
1.68 (m, 1H, 3-Ha), 1.31 and 1.29 (br, 2H, NH and OH), 0.98 and 0.94 (d, 6H, 4-CH3),
0.87 (m, 1H, 4-CH), 0.65 (t, 3H, 3-CH3); 13C NMR (125 MHz, CDCl3):  63.9 (C-2),
45.2 (C-3), 75.5 (C-4), 41.5 (C-5), 56.8 (C-6), 35.1 (4-CH(CH3)2), 17.5 and 16.2 (4CH(CH3)2), 9.5 (3-CH3); MS: m/z 309.45 (M+); Anal. Calcd. for C21H27NO: C, 81.51;
H, 8.79; N, 4.53. Found: C, 81.52; H, 8.77; N, 4.52.
1.2.7: (2S,3R,4S,6R)-3-methyl-4-(propan-2-yl)-2,6-di(furan-2-yl)piperidin-4-ol
(12)
Dark brown viscous oil; Rf Value: 0.59 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3350 (merged, -NH and -OH), 3118 (ArCH); 1H NMR (500 MHz, CDCl3):  7.28-7.55
and 6.21-6.39 (m, 6H, ArH), 4.21 (dd, 3J6a,5a=12.3 Hz, 3J6a,5e=3.3 Hz, 1H, 6-Ha), 3.83 (d,
1H, 2-Ha), 1.80 (m, 3H, 3-Ha, 5-Ha and 5-He), 1.27 (br, 2H, NH and OH), 1.15 and 1.08
(d, 6H, 4-CH3), 0.96 (m, 1H, 4-CH), 0.70 (t, 3H, 3-CH3); 13C NMR (125 MHz, CDCl3):
 60.8 (C-2), 49.9 (C-3), 75.0 (C-4), 39.7 (C-5), 54.1 (C-6), 35.1 (4-CH(CH3)2), 17.4
and 16.1 (4-CH(CH3)2), 9.5 (3-CH3); MS: m/z 289.79 (M+); Anal. Calcd. for
C17H23NO3: C, 70.56; H, 8.01; N, 4.84. Found: C, 70.55; H, 8.03; N, 4.85.
1.2.8: (2S,3R,4S,6R)-3-methyl-4-(propan-2-yl)-2,6-di(4-chlorophenyl)piperidin-4ol (13)
Orange yellow viscous oil; Rf Value: 0.44 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3305 (-NH), 3591 (broad, -OH), 3020 (ArCH); 1H NMR (500 MHz, CDCl3):  7.357.44 and 7.28-7.32 (m, 8H, ArH), 4.21 (dd, 3J6a,5a=11.5 Hz, 3J6a,5e=3.0 Hz, 1H, 6-Ha),
3.87 (d, 3J2a,3a=10.0 Hz, 1H, 2-Ha), 1.68 (m, 1H, 3-Ha), 1.80 (m, 1H, 5-Ha), 1.73 (dd,
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2
J5a,5e=12, 1H, 5-He), 1.85 (br, 2H, NH and OH), 0.83 and 0.77 (d, 6H, 4-CH3), 0.94 (m,
1H, 4-CH), 0.62 (t, 3H, 3-CH3); 13C NMR (125 MHz, CDCl3):  63.1 (C-2), 45.3 (C-3),
75.2 (C-4), 41.8 (C-5), 55.0 (C-6), 35.1 (4-CH(CH3)2), 17.4 and 16.2 (4-CH(CH3)2), 9.3
(3-CH3); MS: m/z 377.34 (M+); Anal. Calcd. for C21H25Cl2NO: C, 66.67; H, 6.66; N,
3.70. Found: C, 66.66; H, 6.68; N, 3.71.
1.2.9: (2S,3R,4S,6R)-3-methyl-4-(propan-2-yl)-2,6-di(4-methoxyphenyl)piperidin4-ol (14)
Pale yellow viscous oil; Rf Value: 0.70 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3321 (-NH), 3396 (broad, -OH), 3060 (ArCH); 1H NMR (500 MHz, CDCl3):  7.357.44 and 7.28-7.32 (m, 8H, ArH), 4.21 (dd, 3J6a,5a=11.5 Hz, 3J6a,5e=3.0 Hz, 1H, 6-Ha),
3.87 (d, 3J2a,3a=10.0 Hz, 1H, 2-Ha), 1.68 (m, 1H, 3-Ha), 1.80 (m, 1H, 5-Ha), 1.73 (dd,
2
J5a,5e=12, 1H, 5-He), 1.85 (br, 2H, NH and OH), 0.83 and 0.77 (d, 6H, 4-CH3), 0.94 (m,
1H, 4-CH), 0.62 (t, 3H, 3-CH3); 13C NMR (125 MHz, CDCl3):  63.1 (C-2), 44.8 (C-3),
73.4 (C-4), 43.0 (C-5), 56.2 (C-6), 33.9 (4-CH(CH3)2), 17.5 and 16.2 (4-CH(CH3)2), 9.2
(3-CH3), 53.9 (OCH3); MS: m/z 369.34 (M+); Anal. Calcd. for C23H31NO3: C, 74.76; H,
8.46; N, 3.79. Found: C, 74.78; H, 8.45; N, 3.78.
1.2.10: (2S,3R,4S,6R)-3-methyl-4-(propan-2-yl)-2,6-di(4-methylphenyl)piperidin4-ol (15)
Orange yellow viscous oil; Rf Value: 0.33 (CHCl3-Benzene = 9:1); IR (KBr, max, cm-1):
3315 (-NH), 3420 (broad, -OH), 3020 (ArCH); 1H NMR (500 MHz, CDCl3):  7.377.41 and 7.15-7.21 (m, 8H, ArH), 4.09 (dd, 3J6a,5a=11.5 Hz, 3J6a,5e=3.0 Hz, 1H, 6-Ha),
3.62 (d, 3J2a,3a=10.0 Hz, 1H, 2-Ha), 2.40 and 2.36 (m, 6H, ArCH3), 1.68 (dd, 2J5a,5e=12,
1H, 5-He), 1.99 (m, 1H, 5-Ha), 1.79 (m, 1H, 3-Ha), 1.31 and 1.26 (br, 2H, NH and OH),
0.89 and 0.85 (d, 6H, 4-CH3), 0.96 (m, 1H, 4-CH), 0.66 (t, 3H, 3-CH3); 13C NMR (75
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MHz, CDCl3):  63.1 (C-2), 44.8 (C-3), 73.4 (C-4), 43.0 (C-5), 56.2 (C-6), 33.9 (4CH(CH3)2), 17.5 and 16.2 (4-CH(CH3)2), 9.2 (3-CH3), 53.9 (OCH3); MS: m/z 337.09
(M+); Anal. Calcd. for C23H31NO: C, 81.85; H, 9.26; N, 4.15. Found: C, 81.87; H, 9.27;
N, 4.13.
1.3: Pharmacology
The in vitro antibacterial and in vitro antifungal activity of the synthesized compounds
were evaluated using the agar diffusion method (Maruthavanan & Venkatesan 2013).
The in vitro antibacterial activity was evaluated against Gram-positive bacteria such as
Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus), and Gram-negative
bacteria such as Escherichia coli (E. coli) and Salmonella typhi (S. typhi). Similarly, the
in vitro antifungal activity was evaluated against pathogenic fungi such as Aspergillus
flavus (A. flavus), Aspergillus niger (A. niger), Penicillium chrysogenum (P.
chrysogenum) and Fusarium moniliforme (F. moniliforme). The in vitro anthelmintic
studies were carried out against three different species of earthworms known as
Megascoplex konkanensis, Pontoscotex corethruses and Eudrilus eugeniea at 2 mg/mL
concentration as reported already (Maruthavanan & Venkatesan 2013).
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Figure S1.1: IR Spectrum of 6
Figure S1.2: NOESY Spectrum of 6
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Table S1. NOESY correlation data of compound 6
Signals
Group
( in ppm)
Correlations in the NOESY
Signals
Group
( in ppm)
C(3)-CH3
0.65
C(2)-Ha
3.86
C(4)-CH2CH3
1.04
C(3)-Ha
1.58-1.64
C(5)-Ha
1.52-1.73
C(4)-OH
1.82
C(5)-He
1.58-1.64
C(4)-CH2CH3
0.91
C(3)-Ha
1.55
C(5)-Ha
1.58-1.64
C(2)-Ha
3.86
C(3)-CH3
0.65
C(6)-Ha
4.24
C(4)-OH
1.82
C(4)-OH
1.82
C(5)-He
1.58-1.64
C(6)-Ha
4.24
Figure S1.3: 1H-NMR Spectrum of 6 (Expanded)
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Figure S1.4: 13C-NMR Spectrum of 6
Figure S2.1: IR Spectrum of 7
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Figure S2.2: 1H-NMR Spectrum of 7 (Expanded)
Figure S2.3: 13C-NMR Spectrum of 7
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Figure S3.1: IR Spectrum of 8
Figure S3.2: 1H-NMR Spectrum of 8 (Expanded)
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Figure S3.3: 13C-NMR Spectrum of 8
Figure S4.1: IR Spectrum of 9
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Figure S4.2: 1H-NMR Spectrum of 9 (Expanded)
Figure S4.3: 13C-NMR Spectrum of 9
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Figure S5.1: IR Spectrum of 10
Figure S5.2: 1H-NMR Spectrum of 10 (Expanded)
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Figure S5.3: 13C-NMR Spectrum of 10
Figure S6.1: IR Spectrum of 11
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Figure S6.2: 1H-NMR Spectrum of 11 (Expanded)
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Figure S6.3: 13C-NMR Spectrum of 11
Figure S7.1: IR Spectrum of 12
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Figure S7.2: 1H-NMR Spectrum of 12 (Expanded)
Figure S7.3: 13C-NMR Spectrum of 12
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Figure S8.1: IR Spectrum of 13
Figure S8.2: 13C-NMR Spectrum of 13
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Figure S8.3: 1H-NMR Spectrum of 13 (Expanded)
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Figure S9.1: IR Spectrum of 14
Figure S9.2: 13C-NMR Spectrum of 14
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Figure S9.3: 1H-NMR Spectrum of 14 (Expanded)
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Figure S10.1: IR Spectrum of 15
Figure S10.2: 1H-NMR Spectrum of 15 (Expanded)
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Figure S10.3: 13C-NMR Spectrum of 15
References:
Maruthavanan T, Venkatesan P. 2013. Synthesis of 4-hydroxy-3,4-dialkyl-2,6diarylpiperidine derivatives as potent antimicrobial agent. Nat Prod Res.
27:238–245.
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