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F. Tamaddon et al. / Journal of Molecular Catalysis A: Chemical 351 (2011) 41–45
COR3
O
2.3. General procedure for sulfonylation of amines and alcohols
1) R2 SO2Cl, ZnO
2) R3 COCl
R1 NH2
R2
S
N
Substrate (amine or alcohol) (2 mmol) was added to a stirred
mixture of ZnO (0.2 mmol, 20 mol% or nanoZnO type I) and sul-
fonylating agent (2 mmol). Then, the reaction mixture was stirred
at ambient temperature for the given times (Table 2). After comple-
tion of the reaction (TLC monitoring), EtOAc (2 × 10 mL) was added
and the precipitated ZnO was filtered off. The resulting organic solu-
tion was washed with NaHCO3 (10%) and dried over anhydrous
Na2SO4. Finally, the solvent was removed to give the sulfonylated
product in 60–95% yields. No further purification was required
for sulfonamides, while sulfonate esters were typically purified by
short column chromatography (Hexane, EtOAc).
R1
O
O
NanoZnO (10 mol %)
or ZnO (20 mol %)
O
R1X
S
R2
R2
1
+ Cl
S
R XH
neat, 50 oC
O
O
R1 = Alkyl, Aryl, Allyl, Benzyl, X = NH, O
R2, R3 = Alkyl, Aryl
Scheme 1. ZnO-catalyzed sulfonylation and acylation.
2. Experimental
2.4. Reusability of catalyst
2.1. Preparation of nanocatalysts
ZnO, nanoZnO type I and nanoZnO type II was regenerated by
simple washing with EtOAc and drying under microwave irradi-
ation. Using the recycled catalysts for three consecutive times in
both sulfonylation and acylation reactions furnished the product
with no significant decreasing in reaction yield.
2.1.1. Preparation of nanoZnO I [30]
Zinc acetate dihydrate (5.5 g) was dissolved in 50 mL of deion-
ized water and then solid NaOH (16 g) was added slowly into the
solution under magnetic stirring at room temperature. A trans-
parent Zn(OH)4 solution was formed. Then 2 mL of ionic liquid
1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide
([bmim][NTf2]) was added to 3 mL of the above solution. The sus-
pension was put into a domestic microwave oven (850 W) in air,
30% of the output power of the microwave was used to irradiate
the mixture for 5 min (on for 10 s, off for 5 s). The white precipitate
was collected by centrifugation, washed with deionized water and
ethanol several times, and dried in vacuum oven at 40 ◦C for 10 h.
The mean particle size of these nanoparticles was 47–37 nm [30].
2.5. Selected spectral data
2.5.1. N-phenyl-N-tosyl acetamide (Table 1, entry 12, compound
Colorless needles (EtOH), Mp = 154–156 ◦C (Lit. 149–150 ◦C [8]).
FT-IR (KBr) ꢀmax: 1700, 1598, 1370, 1267, 1170 cm−1 1H NMR
.
(500 MHz, CDCl3) ı: 1.90 (s, 3H, COCH3), 2.48 (s, 3H, CH3), 7.26–7.30
(m, 2H, Hmeta Ph-N), 7.35 (d, 2H, J = 7.8 Hz, Hortho Ph-CH3), 7.46–7.50
(m, 3H, Hortho,para N-Ph), 7.95 ppm(d, 2H, J = 7.8 Hz, Hmeta Ph-CH3).
13C NMR (125 MHz, CDCl3) ı: 21.50, 25.20, 129.10, 129.30, 130.00,
130.50, 136.20, 140.00, 145.00, 170.30 ppm.
2.1.2. Preparation of nanoZnO II [31]
The ZnO nanoparticles type II was prepared according to
the previously reported procedure [31]. In a typical procedure,
0.22 g (1 mmol) of Zn(CH3CO2)2·2H2O was suspended in 120 mL
of 2-propanol under vigorous stirring at 50 ◦C. A NaOH alco-
holic solution was prepared by adding 0.08 g (2 mmol) NaOH to
30 mL of 2-propanol under vigorous stirring at 50 ◦C. The flasks
containing Zn(CH3CO2)2·2H2O and NaOH alcoholic solution were
cooled in an ice-water bath. The NaOH solution was then added
to Zn(CH3CO2)2·2H2O solution under vigorous stirring to give a
total volume of 150 mL. Final solution was heated up to 80 ◦C by
microwave irradiation. After 5 min, the transparent solution was
obtained. The centrifugation of transparent solution yields white
solid which was then calcined at 600 ◦C for 1 h. The mean particle
size of ZnO nanoparticles was reported as 30 nm [31].
2.5.2. N-butyl-N-tosyl acetamide (Table 1, entry 15, compound
(m))
Thick oil. FT-IR (neat) ꢀmax: 1704, 1596, 1358, 1250, 1168 cm−1
.
1H NMR (500 MHz, CDCl3) (: 0.90 (t, J = 7.5 Hz, 3H, CH2CH3), 1.35 (m,
2H, CH2CH3), 1.65 (m, 2H, NCH2CH2), 2.28 (s, 3H, CH3Ph), 2.38 (s,
3H, CH3CO), 3.80 (t, J = 7.5 Hz, 2H, NCH2CH2), 7.30 (d, J = Hz, 2Harom),
7.75 ppm (d, J = 7.8 Hz, 2Harom).
2.5.3. 1-Octyl tosylate (Table 2, entry 2b)
Thick oil. FT-IR (neat) ꢀmax: 2927, 2857, 1448, 1364, 1188, 1097,
.
J = 7.5 Hz, 3H, CH2CH3), 1.25–1.50 (m, 10H, (CH2)5), 1.60–1.80 (m,
2H, CH2), 3.00 (s, 3H, CH3SO2), 4.20 ppm (t, J = 7.5 Hz, 3H, CH2O).
2.5.4. Pyridin-2-yl-N-tosylmethanamine (Table 2, entry 10)
White needles (H2O:EtOH), Mp = 92–94 ◦C. FT-IR (KBr) ꢀmax
:
2.2. General procedure for the one-pot synthesis of
N-acylsulfonamides
3210, 3060, 1598, 1441, 1327, 1161, 1111, 1090, 817, 762,
660 cm−1 1H NMR (500 MHz, DMSO-d6) ı: 2.37 (s, 3H, CH3Ph), 4.50
.
(d, J = 6.30 Hz, CH2), 7.24 (br t, 1H, NHSO2), 7.35 (m, 3H, 2Hortho
to CH3 and H3 pyridyl, 7.68 (d, J = 6.3 Hz, 2H, Hortho SO2), 7.26
(td, J = 6.3, 1.5 Hz, H4 pyridyl), 8.16 (t, J = 6.3 Hz, H5 pyridyl), 8.43
(d, J = 4.20 Hz, H6 pyridyl) ppm. 13C NMR (125 MHz, DMSO-d6) ı:
149.56, 158.04. Anal. Calcd (%) for C13H14N2O2S: C, 59.52; H, 5.38;
N, 10.68; O, 12.20; S, 12.22; Found C, 59.60; H, 5.48; N, 10.88.
Amine (2 mmol) was added to
a stirred mixture of ZnO
(0.5 mmol) and sulfonylating agent (2 mmol) and the mixture was
stirred at ambient temperature for the given times (Table 1). After
completion of the sulfonylation reaction (TLC monitoring), acylat-
ing agent (2 mmol) was added and the reaction was monitored by
TLC again. Then, EtOAc (2 × 10 mL) was added and the precipitated
ZnO was filtered off. The resulting organic solution was washed
with 10% NaHCO3 and brine, dried over anhydrous Na2SO4, and.
evaporated to give the desired N-acylsulfonamide. The structure of
products was assigned by analysis of their IR, 1H NMR, 13C NMR
spectra and comparison to authentic samples or elemental anal-
ysis. Known products showed physical states; melting points and
spectroscopic data in agreement with authentic samples.
2.5.5. N-glycyl 4-methylbenzenesulfonamide (Table 2, entry 13b)
White needles (EtOH), Mp = 170 ◦C. IR (KBr): 3356, 1317, 1149,
918 cm−1 1H NMR (500 MHz, DMSO-d6) ı: 2.42 (s, 3H, CH3), 3.58
.
(d, J = 6 Hz, 2H, CH2), 6.71 (br s, 1H, NH), 7.26–7.37 (m, 2H, Harom),
7.45–7.73 (m, 2H, Harom), 8.03 (br s,1H, COOH) ppm.