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S.P. Satasia et al. / Journal of Molecular Catalysis A: Chemical 391 (2014) 41–47
Scheme 1. Synthesis of sulfated functionalized choline chloride (IL) and (HIL).
turnover frequency (TOF) and showed chemoselectivity for the
solvent-free formylation of amines.
the aqueous solution of H3W12PO40 (0.005 mol, 14.40 g) at room
temperature (27 1 ◦C) under nitrogen atmosphere(Scheme 1).
The product [Ch-OSO3H]3W12PO40 (HIL), in the form of white
solid was immediately precipitated from the solution. The mixture
was stirred at room temperature (27 1 ◦C) for further 3 h. Solid
product was then filtered, washed with deionized water and dried
in an oven at 60 ◦C. It was characterized by FT-IR, XRD, EDX, TGA
and elemental analysis.
2. Experimental
2.1. Materials and instrumentation
All the reactions were performed with commercially available
reagents. The reactions were monitored by thin-layer chromatog-
raphy carried out on fluorescent coated plates (aluminium plates
coated with silica gel 60 F254, 0.25 mm thickness, Merck) and
detection of the components was made by exposure to UV light.
The synthesized compounds were characterized by 1H NMR spec-
tra recorded in DMSO on Bruker Avance 400 MHz spectrometer
(Bruker Scientific Corporation Ltd., Switzerland). IR spectra were
recorded on Bruker 10 alpha E-FTIR spectrophotometer in the
range 4000–400 cm−1. IR frequencies of only characteristic peaks
are expressed in cm−1. X-Ray powder diffraction (XRD) patterns
were measured on a Philips X-pert MP◦D using Cu K␣ radiation
2.4. Experimental procedures for N-formylation of amines
2.4.1. N-formylation of primary amines using HIL by grindstone
chemistry
0.11 mL) and 20 mg of HIL was thoroughly mixed in a mortar fol-
lowed by grinding at room temperature (27 1 ◦C) (Scheme 2).
The syrupy mixture got solidified within 5–15 min. The mixture
was pulverized till the completion of reaction as indicated by TLC
(Table 4). The reaction mass was then dissolved in ethanol to
recover the insoluble catalyst. The filtered catalyst was dried at
80 ◦C under vacuum for 2 h after thorough washing with ethanol.
Recovered HIL was recycled in the model reaction for six times to
check its catalytic efficiency. The products were recrystallized from
˚
(ꢀ = 1.54056 A) in the range of 2ꢁ 10–70 . The powdered samples
were pressed to pellets and fixed to a stainless steel sample holder
without further treatment. The EDX was performed using Philips
XL 30 scanning electron microscope (SEM). Elemental analyses
were performed on PerkinElmer 2400 series-II elemental analyzer
(PerkineElmer, USA). Elements were found within 0.4% of the
theoretical compositions for all samples. TGA data was obtained
on a TGA/DTG analyzer (TA instruments model 5000/2960 thermo
gravimetric analyzer, USA) at a heating rate of 10 ◦C/min under
static air atmosphere.
hot ethanol. The structures of the products were confirmed by 1
H
NMR, IR spectroscopy and elemental analysis. The spectral data for
all compounds is in good agreement with the reported compounds.
2.5. Selected spectral data of synthesized compounds
N-phenylformamide(3a). Yield: 99%, 1H NMR (400 MHz, DMSO):
ı (ppm) 10.17 (brs, 1H), 8.80 (d, J = 11.20 Hz, trans, 1H), 8.28 (brs,
1H, cis), 7.81 (d, J = 7.56 Hz, 1H, cis), 7.05–7.60 (m, 5H, Ar-H); IR
2.2. Catalyst preparation
(KBr): 3266, 3067, 2760, 1680, 1601, 1543, 1441, 1308, 1148 cm−1
;
(ionic liquid-IL)
Anal. Calcd. C7H7NO(121.1): C, 69.41%; H, 5.82%; N, 11.56%, Found:
C, 69.50%; H, 5.89%; N, 11.52%.
To a magnetically stirred mixture of choline chloride (0.02 mol,
2.79 g) in 20 mL of acetonitrile, chlorosulfonic acid (0.02 mol,
1.33 mL) was added dropwise maintaining the temperature below
5 ◦C over a period of 2 h (Scheme 1). HCl gas, immediately liber-
ated from the reaction vessel, was properly trapped. After complete
addition, the mixture was stirred for further 2 h at room tempera-
ture (27 1 ◦C). The mixture was then filtered, obtained solid was
washed with 30 mL of acetonitrile and dried at room temperature
to afford N,N,N-trimethyl-2-(sulfooxy)ethanaminium chloride (IL).
N-(4-chlorophenyl)formamide(3e). Yield: 98%, 1H NMR
(400 MHz, DMSO): ı (ppm) 10.31 (brs, 1H), 8.79 (d, J = 11.20 Hz,
trans, 1H), 8.29(brs, 1H, cis), 7.20–7.64 (m, 4H, Ar-H); IR (KBr):
3242, 3052, 2750, 1680, 1601, 1543, 1441, 1308, 1148, 723 cm−1
;
Anal. Calcd. C7H6ClNO(155.6): C, 54.04%; H, 3.89%; N, 9.00%, Found:
C, 54.23%; H, 3.75%; N, 9.08%.
N-(3-hydroxyphenyl)formamide(3p). Yield: 95%, 1H NMR
(400 MHz, DMSO) ı 10.04 (brs, 1H, trans), 9.51 (s, 1H, OH), 8.73
(d, 1H, J = 10.8 trans), 8.23 (s, 1H, cis), 6.50 (d, J = 8.8 Hz, 1H, cis)
6.57–7.19 (m, 4H, Ar-H); IR (KBr): 3458, 3284, 2769, 1710, 1589,
1451, 1140 cm−1; Anal. Calcd. C7H7NO2(137.1): C, 61.31%; H, 5.14%;
N, 10.21%, Found: C, 61.52%; H, 5.04%; N, 10.15%.
2.3. Spectral data of N,N,N-trimethyl-2-(sulfooxy)ethanaminium
chloride (IL)
1H NMR: 1H NMR (400 MHz, D2O): ı (ppm) 3.09 (s, 9H),
3.40–3.42 (m, 2H), 3.93–3.97(m, 2H); 13C NMR (100 MHz, D2O):
ı (ppm) 53.8(CH3), 53.8(CH3), 53.9(CH3), 67.4(CH2), 67.4(CH2);
ESIMS, m/z: 185.12 (M + 1).
2.3.1. Preparation of HIL
Under vigorous stirring the aqueous solution of N,N,N-
trimethyl-2-(sulfooxy)ethanaminium chloride (IL, 0.015 mol,
3.30 g) in 25 mL of deionized water was added dropwise into
Scheme 2. Chemoselective N-formylation of amines.