B. Karimi, A.A. Safari / Journal of Organometallic Chemistry 693 (2008) 2967–2970
2969
(125 MHz, CDCl3, 25 °C, TMS): dC = 160.44, 144.68, 129.55, 128.63,
125.94, 120.22, 118.42, 114.21, 114.21, 55.42, 49.70.
OH
CHO
NH2
N
2.4.5. 2-(N-anilino)-2-(3-chlorophenyl) acetonitrile
Absolute EtOH, 18 h
IR (KBr):
m
3356, 3104, 3053, 2901, 2223, 1601, 1500, 1259, 884,
;
SiO2
HO
827, 750 cmÀ1
1H NMR (500 MHz; CDCl3; TMS): dH = 7.60 (s, 1H),
Prepared by both
7.48–7.49 (d, J = 7.4 Hz, 1H), 7.36–7.41 (m, 2H), 7.25–7.28 (t,
J = 8.0 Hz, 2H), 6.89–6.92 (t, J = 7.4 Hz, 1H), 6.74–6.76 (d,
J = 8.0 Hz, 2H), 5.40 (s, 1H), 4.10 (sb, 1H); 13C NMR (125 MHz,
CDCl3, 25 °C, TMS): dC = 144.33, 135.86, 135.31, 130.58, 129.76,
129.62, 127.42, 125.33, 120.63, 117.67, 114.37, 49.74.
grafting and Sol-Gel
H
N
NaBH3CN
Dry MeOH, 72 h
HO
1
2.4.6. 2-(N-anilino)-2-(4-chlorophenyl) acetonitrile
IR (KBr):
m
3299, 3099, 3023, 2948, 2241, 1599, 1490, 1308,
H
N
Sc(OTf)3
CHCl3, 18 h
1273, 1240, 890, 755 cmÀ1
;
1H NMR (500 MHz; CDCl3; TMS):
dH = 7.52–7.53 (d, J = 7.6 Hz, 2H), 7.41–7.43 (d, J = 7.6 Hz, 2H),
7.24–7.28 (t, J = 7.4 Hz, 2H), 6.92–6.89 (t, J = 7.4 Hz, 1H), 6.74–
6.76 (d, J = 7.4 Hz, 2H), 5.40 (s, 1H), 4.05 (sb, 1H); 13C NMR
(125 MHz, CDCl3, 25 °C, TMS): dC = 144.38, 135.59, 132.45,
129.61, 129.52, 128.59, 120.58, 117.84, 114.36, 49.66.
(TfO)2Sc
O
2
Scheme 1. Preparation of silica-based scandium (III) interphase catalyst 2.
2.4.7. 2-(N-anilino)-2-(2-methylphenyl) acetonitrile
a loading at c.a. 0.3 mmol gÀ1 was obtained [40]. Similarly, TGA/
DTA analyses of immobilized scandium 2 were performed and
shows a first peak due to the desorption of water (centered at
110 °C). This is followed by a second peak at 375 °C, corresponding
to the loss of triflate groups accompanied by a third peak centered
at 535 °C, which corresponds to the loss of the surface bound biden-
tate ligand. Typical loading of scandium was determined using
IR (KBr):
m
3346, 3025, 2924, 2234, 1598, 1509, 1443, 1282,
1242, 918, 878, 756 cmÀ1
;
1H NMR (500 MHz; CDCl3; TMS):
dH = 7.36–7.40 (m, 2H), 7.31–7.34 (t, J = 7.5 Hz, 1H), 7.22–7.28 (m,
3H), 6.87–6.90 (t, J = 7.5 Hz, 1H), 6.75–6.77 (d, J = 7.5 Hz, 2H),
5.36 (s, 1H), 3.99 (sb, 1H), 2.39 (s, 3H); 13C NMR (125 MHz, CDCl3,
25 °C, TMS): dC = 144.72, 139.31, 133.88, 130.27, 129.56, 129.21,
127.90, 124.33, 120.24, 118.31, 114.16, 50.22, 21.38.
atomic spectroscopy (AA) and shows
a loading 0.29 0.01
mmol gÀ1. This result in combination with TGA analyses demon-
strates that 2 corresponds to a 1:1 and 2:1 complex between sur-
face bound and triflate ligands with scandium, respectively
(Scheme 1) [40]. We have also demonstrated that 2 is an efficient
heterogeneous catalyst for cyanosilylation of carbonyl compounds
and could be easily recovered and reused for at least ten reaction
cycles without significant loss of its reactivity [39].
In continuation of our investigations into the development of
new efficient and recyclable solid-based catalyst for functional
group transformations [41–51], herein, we wish to present that
catalyst 2 (5–6 mol% equivalent to Sc) is a highly powerful catalyst
2.4.8. 2-(N-anilino)-2-(3-methoxyphenyl) acetonitrile
IR (KBr):
m
3352, 3089, 3065, 3028, 2934, 2225, 1595, 1093,
1016, 918, 820, 742 cmÀ1
;
1H NMR (500 MHz; CDCl3; TMS):
dH = 7.31–7.34 (t, J = 8.0 Hz, 1H), 7.22–7.26 (t, J = 8.0 Hz, 2H),
7.14–7.15 (d, J = 8.0 Hz, 1H), 7.09 (s, 1H), 6.92–6.94 (dd,
J = 8.0 Hz, J = 1.6 Hz, 1H), 6.86–6.89 (t, J = 8.0 Hz, 1H), 6.73–6.74
(d, J = 8.0 Hz, 2H), 5.35 (s, 1H), 4.10 (sb, 1H), 3.78 (s, 3H); 13C
NMR (125 MHz, CDCl3, 25 °C, TMS): dC = 160.22, 144.68, 135.39,
130.38, 129.52, 120.19, 119.32, 118.22, 115.08, 114.16, 112.74,
55.38, 50.09.
for the three-component Strecker synthesis of a-aminonitrilesin in
2.4.9. 2-(N-anilino)-2-(3-methylphenyl) acetonitrile
excellent yields at ambient temperature and in the absence of any
chemical dehydrating agent (Scheme 2).
IR (KBr):
m ;
3351, 3049, 2923, 2231, 1598, 1271, 935, 753 cmÀ1
1H NMR (500 MHz; CDCl3; TMS): dH = 7.68–7.70 (d, J = 7.4 Hz, 1H),
7.22–7.36 (m, 5H), 6.88–6.91 (t, J = 7.4 Hz, 1H), 6.76–6.78 (d,
J = 7.4 Hz, 2H), 5.46 (s, 1H), 3.84 (sb, 1H), 2.37 (s, 3H); 13C NMR
(125 MHz, CDCl3, 25 °C, TMS): dC = 144.84, 136.48, 132.08,
131.33, 129.75, 129.62, 127.57, 126.93, 120.16, 118.38, 113.88,
48.09, 18.66.
First, we examined the Strecker reaction of benzaldehyde with
aniline and TMSCN (1.2 equiv.) in the absence of 2. In this case,
the reaction did not proceed even after 24 h (Table 1, entry 1).
However, the same reaction in the presence of a catalytic amount
of 2 (equivalent to 5 mol% Sc) smoothly afforded the corresponding
2-(N-anilino)-2-phenyl acetonitrile in 94% isolated yield (Table 1,
entry 2) [19]. Similarly, various types of structurally diverse
aromatic aldehydes with either electron-withdrawing or elec-
tron-donating groups were converted to the corresponding
2.4.10. 2-(4-Bromophenylamino)-2-phenylacetonitrile
IR (KBr):
m 3320, 3061, 3028, 2933, 2230, 1599, 1273, 918,
748 cmÀ1 1H NMR (500 MHz; CDCl3; TMS): dH = 7.52–7.53 (d,
;
a-aminonitriles in good to excellent yields (Table 1, entries 3–
J = 4.0 Hz, 2H), 7.42–7.43 (d, J = 4.0 Hz, 3H), 7.30–7.32 (d,
J = 8.4 Hz, 2H), 6.60–6.62 (d, J = 8.4 Hz, 2H), 5.34 (s, 1H), 4.16 (sb,
1H); 13C NMR (125 MHz, CDCl3, 25 °C, TMS): dC = 143.64, 133.40,
132.27, 129.62, 129.36, 127.15, 117.89, 115.77, 112.16, 50.04.
10). It is also worth mentioning that using 2 as catalyst various
types of aldehydes including aliphatic ones underwent the one-
pot three-component Strecker reaction with 3-phenylpropylamine
and TMSCN giving the corresponding
a-aminonitriles in good to
excellent yields (Table 1, entries 11–16). We have also studied a
possible one-pot three-component Strecker reaction with aid of
secondary amines like morpholine. Interestingly, we found that
3. Results and discussion
Very recently, we addressed this issue by designing and prepar-
ing of a novel silica-based scandium (III) interphase catalyst (cata-
lyst 2, Scheme 1) [39].
Quantitative determination of the functional group contents of
the surface bound compound 1 was performed with thermogravi-
metric analysis/differential thermal analysis (TGA/DTA). Typically,
NHR2
CN
O
2 (5-6 mol%)
TMSCN, CH2Cl2, rt., 14 h
R2 NH2
R1
H
R1
Scheme 2. One-pot Strecker reaction of carbonyl compounds using 2.