with toluene and hexane (v/v, 5 : 1). A yellow solid was obtained
4,4ꢀ-Methylenebis(2-bromo-N-cyclohexylaniline) (9)
1
(0.27 g, 80%). IR (neat): 3456 and 3448 (N–H) cm−1. H NMR
4,4ꢀ-Methylenebis(N-cyclohexylaniline) (8.75 g, 24.1 mmol) was
dissolved in methylene chloride (80 mL) and a solution of Br2
(7.72◦g, 48.29 mmol) in methylene chloride (10 mL) was added
at 0 C over 30 min. The solution was stirred for a further 2 h.
After an aqueous KOH solution (1 N, 200 mL) was added, the
product was extracted with methylene chloride (300 mL × 2).
The combined organic layers were dried over anhydrous MgSO4
and the solvent was removed with a rotary evaporator to give a
residue which was purified by column chromatography on silica
gel eluting with hexane and ethyl acetate (30 : 1). A white solid was
obtained (9.58 g, 52%); mp 97 ◦C, IR (neat): 3401 (N–H) cm−1. 1H
NMR (C6D6): d 0.93–1.17 (m, 10H, Cy), 1.38–1.42 (m, 2H, Cy),
1.52–1.57 (m, 4H, Cy), 1.79–1.82 (m, 4H, Cy), 3.01–3.07 (m, 2H,
N–CH), 3.54 (s, 2H, bridged-CH2), 4.22 (d, J = 8.0 Hz, 2H, NH),
6.45 (d, J = 8.0 Hz, 2H, C6H3), 6.89 (dd, J = 8.0 Hz, 1.6 Hz,
(C6D6): d 1.90 (s, 3H, CH3), 1.91 (s, 3H, CH3), 1.98 (d, J = 1.6 Hz,
3H, CH3), 2.00 (d, J = 2.0 Hz, 3H, CH3), 2.24 (s, 3H, Ph-CH3),
2.84 (t, J = 1.6 Hz, 2H, CH2), 3.37 (br d, J = 2.8 Hz, 2H, NH2),
1
5.98 (d, J = 1.6 Hz, 2H, Cp-H), 6.87 (s, 2H, C6H2) ppm. 13C{ H}
NMR (C6D6): d 14.94, 14.98, 15.01, 15.10, 20.09, 44.64, 122.24,
122.31, 124.59, 124.64, 126.03, 126.12, 130.01, 130.09, 140.64,
140.69, 140.83, 140.86, 140.95, 144.20, 144.34 ppm. Anal. calc.
(C21H25N): C, 86.55; H, 8.65; N, 4.81%. Found: C, 86.42; H, 8.42;
N, 4.71%.
Complex 7
Compound 5 (0.224 g, 0.77 mmol), Ti(NMe2)4 (0.345 g,
1.54 mmol), and toluene (10 mL) were added to a Schlenk flask.
The solution was stirred for 1 d at 80 ◦C. Removal of the solvent
1
2H, C6H3), 7.34 (d, 2H, J = 1.2 Hz, C6H3) ppm. 13C{ H} NMR
1
gave a red oil found to be pure through a H NMR spectrum
(C6D6): d 25.16, 26.24, 33.29, 39.78, 51.80, 110.28, 112.30, 129.15,
130.88, 133.07, 142.75 ppm. Anal. calc. (C25H32Br2N2): C, 57.71;
H, 6.20; N, 5.38%. Found: C, 58.09; H, 6.48; N, 5.52%.
analysis. 1H NMR (C6D6): d 2.02 (s, 12H, CH3), 2.31 (s, 3H, Ph-
CH3), 3.11 (s, 24H, N–CH3), 5.72 (s, 4H, Cp-H), 6.93 (s, 2H,
C6H2) ppm. Me2SiCl2 (0.600 g, 4.65 mmol) was added to a flask
containing the resulting bis(dimethylamido)titanium complex in
toluene (10 mL). After the solution was stirred for 12 h at room
temperature, all volatiles were removed under vacuum to give
dark red crystals which were triturated with pentane (10 mL)
(0.321 g, 80%). Analytically pure crystals of 7 were obtained from
Compound 12
The compound was synthesized using the same conditions and
procedure as for 3 using 9 (4.15 g, 7.98 mmol). It was purified by
column chromatography on silica gel eluting with hexane and ethyl
acetate (3 : 1). A white solid was obtained (4.18 g, 91%). Owing to
the presence of two chiral centers, it was obtained as a mixture of
two diastereomers and some signals are split in the NMR spectra;
◦
1
the toluene solution at −30 C. H NMR (CDCl3): d 2.21 (s,
12H, CH3), 2.48 (s, 3H, Ph-CH3), 6.69 (s, 4H, Cp-H), 7.05 (s,
1
2H, C6H2) ppm. 13C{ H} NMR (CDCl3): d 15.46, 21.09, 118.95,
122.68, 128.78, 135.09, 140.05, 143.03, 174.02 ppm. Anal. calc.
(C21H21Cl4NTi2): C, 48.05; H, 4.03; N, 2.67%. Found: C, 47.90; H,
3.95; N, 2.62%.
◦
−1
1
=
mp 164–166 C. IR (neat): 3456 (N–H), 1631 (C O) cm . H
NMR (C6D6): d 0.74 (d, J = 6.8 Hz, 6H, CH3), 1.17–1.20 (m, 10H,
Cy), 1.42–1.45 (m, 2H, Cy), 1.57–1.62 (m, 4H, Cy), 1.66 (s, 6H,
CH3), 1.82 (dd, J = 18.4, 2.0 Hz, 2H, CH2), 1.92–2.07 (m, 4H, Cy),
2.16–2.19 (m, 2H, CH), 2.41 (dd, J = 18.4, 6.4 Hz, 2H, CH2), 3.18
(br s, 2H, N–CH), 3.98 (s, 2H, bridged-CH2), 6.74 (d, J = 8.0 Hz,
2H, C6H3), 6.98 (d, J = 2.4 Hz, 2H, C6H3) 7.21 (dd, J = 8.0, 2.4 Hz,
4,4ꢀ-Methylenebis(N-cyclohexylaniline)
4,4ꢀ-Methylenebis(aniline) (10.0 g, 50.44 mmol) and cyclohex-
anone (39.6 g, 0.404 mol) were dissolved in toluene (80 mL) and
then molecular sieves (15.0 g) were added. The flask was sealed
with a screw-cap and heated at 100 ◦C for 4 d. After the molecular
sieves◦were filtered off, all volatiles were removed under vacuum
at 60 C to give a crude imine compound. The imine compound
was dissolved in degassed methanol (200 mL) and THF (50 mL).
Sodium borohydride (11.5 g, 0.303 mol) was added slowly under a
weak stream of nitrogen gas and the mixture was stirred at room
temperature for 5 h. Aqueous 1 N KOH (200 mL) was added and
the product was extracted with methylene chloride (250 mL × 2).
The combined organic layers were dried over anhydrous MgSO4
and solvent was removed with a rotary evaporator to give a residue
which was purified by recrystallization from hexane and ethyl
acetate (10 : 1). A light yellow solid was obtained (9.58 g, 52%);
2H, C6H3) ppm. 13C{ H} NMR (C6D6): d 16.29, 19.38, 25.27,
1
26.53, 33.74, 37.74, 40.78, 43.73, 51.99, 112.51, 119.22, 129.97,
130.15, 131.53, 132.00, 132.32, 132.41, 144.58, 177.01, 205.33 ppm.
Anal. calc. (C39H50N2O2): C, 80.93; H, 8.71; N, 4.84%. Found: C,
81.15; H, 8.94; N, 5.03%.
Compound 15
La(OTf)3 (1.823 g, 3.11 mmol) and THF (15 mL) were added to
a Schlenk flask inside a glovebox. The flask was brought out and
the solution was cooled to −78 ◦C. MeLi (3.11 mmol) was added
using a syringe. The solution was warmed to room temperature
◦
and stirred for 1 h. After the solution was cooled to −78 C, 12
(0.300 g, 0.52 mmol) dissolved in THF (1.0 mL) was added. The
◦
◦
1
mp 116 C. H NMR (C6D6): d 0.84–0.94 (m, 4H, Cy), 1.02–
1.20 (m, 6H, Cy), 1.46–1.58 (m, 6H, Cy), 1.89–1.92 (m, 4H, Cy),
3.04–3.10 (m, 2H, N–CH), 3.05 (d, J = 6.4 Hz, 2H, NH), 3.91 (s,
2H, bridged-CH2), 6.47 (d, J = 8.0 Hz, 4H, C6H4), 7.13 (d, J =
mixture was stirred for 2 h at −78 C. After an aqueous NaOH
solution (20 mL, 1 M) was added, the organic phase was extracted
with ethyl acetate (20 mL × 2). The combined organic phases
were washed with water (40 mL) and were shaken vigorously with
aqueous HCl solution (2 N, 10 mL) for 3 min. Aqueous saturated
NaHCO3 (20 mL) was added carefully to neutralize the solution.
The collected organic phase was dried over anhydrous MgSO4
and the solvent was removed with a rotary evaporator to give a
1
8.0 Hz, 4H, C6H4) ppm. 13C{ H} NMR (C6D6): d 25.48, 26.50,
33.81, 41.00, 51.96, 113.73, 130.03, 130.84, 145.91 ppm. Anal. calc.
(C25H34N2): C, 82.82; H, 9.45; N, 7.73%. Found: C, 83.03; H, 9.38;
N, 7.62%.
4612 | Dalton Trans., 2007, 4608–4614
This journal is
The Royal Society of Chemistry 2007
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