B. Urbán et al. / Molecular Catalysis 445 (2018) 195–205
197
reflux, 1 l phosphoric acid (85%, 0.012 mmol) was added and the
mixture was refluxed for 12 h. The hot reaction mixture was filtered
by filtration and was reused without further purification. The reac-
tion mixture was analysed by gas chromatography.
After the evaporation of the solvent of the reaction mixture,
the products were purified by column chromatography (silica, elu-
ent: ethyl acetate (9aa); toluene: acetone = 4:1 (9ab, 9ac, 9ad, 9ba,
9ca, 9ea, 10da); toluene: tert-butyl alcohol = 4:1 (10ae, 10af, 10ag,
10ah).
under inert conditions and was washed with 30 ml methanol and
◦
5
1
ml diethyl ether and then dried in vacuo at 60 C for 8 h to obtain
.028 g of 3.
A mixture of the modified silica gel 3 (1.0 g), 2.26 g of (3-
bromopropyl) triphenylphosphonium bromide (4) (4.87 mmol),
prepared by a known method [35] and 10 ml toluene were refluxed
under argon for 24 h. The solid material was filtered under inert
conditions and washed with 3 × 5 ml toluene and 3 × 5 ml diethyl
2
2
.4. Characterisation of the products
◦
ether and then dried in vacuo at 60 C for 8 h to obtain 1.08 g of sup-
.4.1. 1-Morpholino-2-phenylethane-1,2-dione (9aa) [16]
ported ionic liquid phase SILP-2. Based on the weight increase and
thermogravimetric analysis of SILP-2 (organic content: 16.5%) 32%
of the surface imidazole moieties were alkylated. This corresponds
to 0.16 mmol dicationic moieties/g modified silica.
1
H NMR (␦, CDCl ): 7.97–7.95 (m, 2H); 7.66 (tt, J = 7.4 Hz,
3
J = 1.2 Hz, 1H); 7.54–7.51 (m, 2H); 3.82–3.78 (m, 4H); 3.67–3.65 (m,
13
2
1
(
H); 3.40–3.38 (m, 2H). C NMR (␦, CDCl ): 191.1; 165.5; 134.9;
3
33.1; 129.7; 129.1; 66.7; 66.6; 46.3; 41.6. MS(m/z/rel.int.): 219
M )/6; 114/11; 105/100; 86/4; 77/54; 70/26; 51/22.
+
2
.2. Preparation of catalysts
.2.1. Preparation of CAT-0
2
.4.2. 1-Phenyl-2-(pyrrolidin-1-yl)ethane-1,2-dione (9ab) [26]
2
1
H NMR (␦, CDCl ): 7.98–8.06 (m, 2H); 7.61–7.65 (m, 1H);
2
00 mg [MePh P][Br] and 0.02 mmol (20.7 mg) Pd (dba) ·CHCl
3
3
2
3
3
7
(
.48–7.52 (m, 2H); 3.64–3.67 (m, 2H); 3.41–3.44 (m, 2H); 1.89–2.00
(
dba = dibenzylideneacetone) was dissolved in 5 ml acetonitrile.
m, 4H). 13C NMR (␦, CDCl ): 191.1; 164.4; 134.1; 132.5; 129.4;
The mixture was stirred for 15 min at room temperature. Then
3
+
1
28.4; 46.2; 44.8; 25.4; 23.5. MS(m/z/rel.int.): 203(M )/3; 202/6;
5
50 mg silica (Kieselgel 60 (0.040–0.063 mm), Merck, pre-treated
◦
105/71; 98/100; 77/52; 70/31; 55/56.
by heating for 5 h at 250 C) was added under stirring and the
resulting mixture was stirred for 24 h. The solvents were removed
in vacuo and the catalyst was dried at 40 C in vacuo for 3 h and
◦
2
.4.3. 1-Phenyl-2-(piperidin-1-yl)ethane-1,2-dione (9ac) [16]
was stored under argon until use. Palladium content of the catalyst:
1
H NMR (␦, CDCl ): 7.90–7.93 (, 2H); 7.59–7.63 (m, 1H);
3
0.54% (determined by ICP-AES).
7
(
.44–7.51 (m, 2H); 3.66–3.70 (m, 2H); 3.24–3.28 (m, 2H); 1.64–1.69
m, 4H); 1.48–1.55 (m, 2H). 13C NMR (␦, CDCl ): 191.9; 165.4; 134.5;
3
2.2.2. Preparation of CAT-1 and CAT-2
1
33.2; 129.4; 128.9; 46.9; 42.0; 26.1; 25.4; 24.3. MS(m/z/rel.int.):
A solution of 120 mg Pd (dba) ·CHCl (0.115 mmol) in 4 ml THF
+
2
3
3
217(M )/5; 112/100; 105/54; 84/10; 77/33; 69/61; 51/11; 41/29.
and 4 ml acetonitrile was stirred for 15 min under inert conditions
at room temperature. Then 1 g modified silica gel (SILP-1 or SILP-2)
was added and the resulting mixture was stirred for 24 h at room
2
.4.4. N,N-Diethyl-2-oxo-2-phenylacetamide (9ad) [16]
1
H NMR (␦, CDCl ): 7.93 (d, J = 7.5 Hz, 2H); 7.63 (t, J = 7.5 Hz, 1H);
3
temperature. The solvents were evaporated and the catalyst was
◦
7.50 (t, J = 7.5 Hz, 2H); 3.56 (q, J = 7.1 Hz, 2H); 3.24 (q, J = 7.1 Hz, 2H);
dried in vacuo at 50 C for 6 h. Palladium content of the catalysts:
1
1
.29 (t, J = 7.1 Hz, 3H); 1.15 (t, J = 7.1 Hz, 3H). 13C NMR (␦, CDCl ):
3
0.75% (CAT-1) and 1.95% (CAT-2) (determined by ICP-AES).
91.5; 166.7; 134.5; 133.3; 129.6; 128.9; 42.1; 38.8; 14.1; 12.8.
+
MS(m/z/rel.int.): 205(M )/5; 105/61; 100/100; 77/42; 72/74; 51/21.
2.2.3. Preparation of CAT-3
A solution of 20.7 mg Pd (dba) ·CHCl (0.115 mmol) in 4 ml THF
2
3
3
and 4 ml acetonitrile was stirred for 15 min under inert conditions
2.4.5. 1-(4-Methoxyphenyl)-2-morpholinoethane-1,2-dione
at room temperature. Then 550 mg modified silica gel (SILP-2) was
(9ba) [32]
1
added and the resulting mixture was stirred for 24 h at room tem-
H NMR (␦, CDCl ): 7.93 (d, J = 8.9 Hz, 2H); 6.98 (d, J = 8.9 Hz, 2H);
3
◦
perature. The solid material was filtered and dried in vacuo at 50 C
3.90 (s, 3H); 3.76–3.82 (m, 4H); 3.64–3.66 (m, 2H); 3.37–3.39 (m,
2H). 13C NMR (␦, CDCl ): 189.8; 165.8; 165.0; 132.2; 126.2; 114.4;
for 6 h. Palladium content of the catalyst: 0.74% (determined by
ICP-AES).
3
+
66.8; 66.7; 55.7; 46.3; 41.6. MS(m/z/rel.int.): 249(M )/3; 136/12;
1
35/100; 114/3; 107/11; 92/10; 77/14; 70/8; 64/5.
2.3. General procedures for catalytic reactions
2
.4.6. 1-(3,4-Dimethylphenyl)-2-morpholinoethane-1,2-dione
2
.3.1. Catalytic reactions at atmospheric pressure
In a typical experiment a solution containing the palladium cat-
(
9ca) [26]
1
H NMR (␦, CDCl ):7.70 (s, 1H); 7.66(d, J = 8.0 Hz, 1H); 7.25 (d,
3
alyst (with 2.8 mol Pd-content) was placed in a Schlenk-tube.
Under argon, 0.2 mmol (22.5 l) iodobenzene (7a), 0.5 mmol (44 l)
morpholine (8a), 0.25 mmol (35 l) triethylamine and 1 ml DMF
was added and the atmosphere was changed to carbon monoxide.
The reaction was conducted for 3 or 8 h at 100 C. The catalyst was
removed by filtration and the reaction mixture was analysed by GC
and GC–MS.
J = 8.0 Hz, 1H); 3.74–3.79 (m, 4H); 3.60–3.64 (m, 2H); 3.33–3.36
(
m, 2H); 2.32 (s, 3H); 2.30 (s, 3H) ppm. 13C NMR (␦, CDCl ):
3
1
4
1
91.1; 165.7; 145.0; 137.6; 130.9; 130.4; 130.3; 127.4; 66.6 (2C);
+
6.2; 41.5; 20.2; 19.6 ppm. MS(m/z/rel.int.): 247(M )/3; 133/100;
◦
05/24; 79/9; 77/9; 70/9.
2.4.7. 1-(4-Bromophenyl)-2-morpholinoethane-1,2-dione (9ea)
[
26]
2
.3.2. Catalytic reactions at elevated pressure
In a typical experiment the catalyst (containing 2.8 mol Pd)
1
H NMR (␦, CDCl ):7.83 (d, J = 8.5 Hz, 2H); 7.67 (d, J = 8.5 Hz,
3
13
2
H); 3.77–3.81 (m, 4H); 3.65–3.68 (m, 2H); 3.37–3.40 (m, 2H).
C
was placed in a stainless steel autoclave. The aryl iodide (0.2 mmol),
amine (0.5 mmol), base (35 l, 0.25 mmol) and solvent (1 ml) were
transferred into it under an inert atmosphere. It was charged with
carbon monoxide (30 bar) and heated with stirring in an oil bath at
1
NMR (␦, CDCl ): 189.9; 164.9; 132.5; 131.9; 131.1; 130.5; 66.8;
6
1
3
+
+
6.7; 46.3; 41.7. MS(m/z/rel.int.): 299(M )/6; 297(M )/6; 185/100;
83/100; 157/20; 155/20; 114/93; 86/31; 76/22; 75/19; 70/83;
◦
42/27
00 C. After cooling to room temperature the catalyst was removed