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Med Chem Res (2011) 20:769–781
Experimental
filtration. The crude amide was recrystallized from alcohol.
In the case of anilides, the precipitated crude anilide was
treated with 5% hydrochloric acid, 4% sodium carbonate
and water to remove residual aniline, and the resultant
anilide was recrystallized from alcohol.
Starting materials were obtained from commercial sources
and were used without further purification. Reaction pro-
gress was observed by thin layer chromatography making
use of commercial silica gel plates (Merck). Melting points
were determined in open capillary tubes on a Sonar melting
Compound 1: Yield—45.2%; mp—195°C; IR (cm-1):
3297 (NH str., amide), 2929 (CH str., aliphatic), 1636
1
1
(C=O str., aromatic), 1500 (C=C str., aromatic); H NMR
point apparatus and are uncorrected. H nuclear magnetic
resonance (1H NMR) spectra were determined by Bruker
Avance II 400 NMR spectrometer in appropriate deuter-
ated solvents and are expressed in parts per million (d,
ppm) downfield from tetramethylsilane (internal standard).
NMR data are given as multiplicity (s, singlet; d, doublet; t,
triplet; m, multiplet) and number of protons. Infrared (IR)
(d ppm): 8.26 (s,1H, NH), 3.61–3.63 (m, 1H, CH of
cyclohexyl), 2.13–2.15 (t, 2H, CH2 of COCH2), 1.55–1.92
(m, 10H, CH2 of cyclohexyl), 1.28–1.41 (m, 18H, CH2 of
(CH2)9CH3), 0.86–0.89 (t, 3H, CH3); Compound 2:
Yield—45.4%; mp—175°C; IR (cm-1): 3297 (NH str.,
amide), 3020 (CH str., aromatic), 2917 (CH str., aliphatic),
1631 (C=O str., amide), 1453 (C=C str, aromatic); 1H
NMR (d ppm): 7.26–7.35 (m, 5H, ArH), 5.71 (s, 1H, NH),
2.17–2.23 (t, 2H, CH2 of NHCOCH2), 1.25–1.67 (m, 18H,
CH2 of (CH2)9 CH3), 0.86–0.89 (t, 3H, CH3); Compound 7:
Yield—58.0%; mp—99°C; IR (cm-1): 3262 (NH str.,
amide), 3147 (CH str., aromatic), 2922 (CH str., aliphatic),
1667 (C=O str., amide), 1582 (C=C str, aromatic); 1H
NMR (d ppm): 11.28 (s, 1H, NH), 8.34–8.36 (d, 1H, CH of
C2 of pyridine), 8.11–8.13 (d,1H, CH of C6 of pyridine),
7.69–7.78 (m, 2H, CH of C4 and C5 of pyridine), 2.33–2.37
(t, 2H, CH2 of COCH2), 1.62–1.75 (m, 2H, terminal CH2 of
COCH2CH2), 1.23–1.37 (m, 16H, CH2 of (CH2)8CH3),
0.86–0.89 (t, 3H, CH3); Compound 8: Yield—61.2%;
mp—85°C; IR(cm-1): 3301 (NH str., amide), 3058 (CH
str., aromatic), 2917 (CH str., aliphatic), 1706 (C=O str.,
amide), 1551 (C=C str, aromatic); 1H NMR (d ppm): 11.39
(s, 1H, NH), 9.57 (s, 1H, CH of C2 of pyridine), 8.90–8.92
(d, 1H, CH of C6 of pyridine), 8.55 (d, 1H, CH of C4 of
pyridine), 8.11–8.13 (d, 1H, CH of C6 of pyridine),
7.83–7.87 (m, 1H, CH of C5 of pyridine), 2.55–2.59 (t, 2H,
CH2 of COCH2), 1.61–1.71 (m, 2H, terminal CH2 of
COCH2 CH2), 1.25–1.29 (m, 16H, CH2 of (CH2)8CH3),
0.86–0.89 (t, 3H, CH3); Compound 10: Yield—58.3%;
mp—110°C; IR(cm-1): 3300 (NH str., amide), 2919 (CH
spectra were recorded on
spectrometer.
a Perkin Elmer FTIR
General procedure for synthesis of ester derivatives
of dodecanoic acid (19–28)
A mixture of dodecanoic acid (0.08 mol) and appropriate
alcohol (0.74 mol) was heated under reflux in presence of
sulphuric acid till the completion of reaction, which was
checked by single spot TLC. Then the reaction mixture was
added to 200 ml ice-cold water, neutralized with sodium
bicarbonate solution followed by the extraction of ester
with ether (50 ml). The ether layer was separated, which on
evaporation yielded the ester derivatives of dodecanoic
acid.
General procedure for synthesis of phenolic ester
derivatives of dodecanoic acid (4–6, 18, 29–30)
The acid chloride of dodecanoic acid was prepared by
reaction of dodecanoic acid with thionyl chloride. A
solution of 8-hydroxy quinoline/corresponding phenol
(0.05 mol) in ether (50 ml) was added to a solution of
dodecanoyl chloride (0.05 mol) in ether (50 ml). The
mixture was heated on a water bath until no further evo-
lution of hydrogen chloride was observed, and completion
of reaction was checked by single spot TLC. The mixture
was cooled to room temperature, and evaporation of sol-
vent yielded the crude product which was purified by
recrystallization from alcohol.
1
str., aliphatic), 1634 (C=O str., amide); H NMR (d ppm):
6.37 (s, 1H, NH), 2.78–2.79 (d, 3H, CH3 of (CH3NH),
2.16–2.20 (t, 2H, CH2 of COCH2), 1.58–1.63 (m, 2H, ter-
minal CH2 of COCH2CH2), 1.25–1.28 (m, 16H, CH2 of
(CH2)8 CH3), 0.86–0.89 (t, 3H, CH3); Compound 12:
Yield—43.0%; mp—143°C; IR (cm-1): 3315 (NH str.,
amide), 2921 (CH str., aliphatic), 1646 (C=O str., amide);
1H NMR (d ppm): 6.14 (t, 1H, NH), 4.01–4.03 (t, 1H, OH),
3.61 (m, 4H, CH2 of COCH2CH2), 2.19–2.23 (t, 2H, CH2
of COCH2), 1.63 (m, 2H, terminal CH2 of COCH2 CH2),
1.25–1.29 (m, 16H, CH2 of (CH2)8CH3), 0.86–0.89 (t, 3H,
CH3); Compound 13: Yield—45.6%; mp—160°C; IR
(cm-1): 3305 (NH str., amide), 2925 (CH str., aliphatic),
General procedure for synthesis of amides/anilides
derivatives of dodecanoic acid (1–3, 10–17)
The solution of corresponding amine (0.1 mol)/aniline
(0.1 mol) in ether (50 ml) was added drop wise to a solu-
tion of acid chloride (0.1 mol) in ether (50 ml) maintained
at 0–10°C/room temperature. The solution was stirred for
30 min and the precipitated amide was separated by
1
1638 (C=O str., amide); H NMR (d ppm): 5.40 (s, 1H,
NH), 4.05–4.15 (m, 1H, CH), 2.11–2.30 (t, 2H, CH2 of
123