Synthesis and molecular structures of (2-dialkylaminophenyl)alcohols and of 2-phenylaminoalkyl-dimethylaminobenzene derivatives

Article abstract of DOI:10.1016/j.tet.2003.11.022

N,N-Dimethyl-o-toluidine, N,N-dimethylaniline, and N,N-diethylaniline were treated with n-butyllithium-tmeda in diethyl ether-hexane solution to give o-lithioarylamines, which react with various electrophiles (benzophenone, dicyclohexyl ketone, benzaldehy

Full text of DOI:10.1016/j.tet.2003.11.022

Tetrahedron 60 (2004) 333–339
Synthesis and molecular structures of
(2-dialkylaminophenyl)alcohols and of
2-phenylaminoalkyl-dimethylaminobenzene derivatives
†
†
†
,
a
Harbi Tomah Al-Masri,a Joachim Sieler,a Peter Lonnecke, Steffen Blaurock,a
,
,
¨
†
Konstantin Domasevitchb and Evamarie Hey-Hawkinsa
,
,
*
a
¨
¨
Institut fur Anorganische Chemie der Universitat Leipzig, Johannisallee 29, D-04103 Leipzig, Germany
bInorganic Chemistry Department, Kiev University, Volodimirska Str. 64, Kiev, Ukraine
Received 22 July 2003; revised 3 November 2003; accepted 7 November 2003
Abstract—N,N-Dimethyl-o-toluidine, N,N-dimethylaniline, and N,N-diethylaniline were treated with n-butyllithium-tmeda in diethyl
ether–hexane solution to give o-lithioarylamines, which react with various electrophiles (benzophenone, dicyclohexyl ketone,
benzaldehyde, and Ph(H)CvNPh) to form the corresponding (2-dialkylaminophenyl)alcohols 1-HOCPh2-2-NMe2C6H4 (1), 1-HOCCy2-
2-NMe2C6H4 (2), 1-HOCPh2CH2-2-NMe2C6H4 (4), 1-HOC(H)PhCH2-2-NMe2C6H4 (6), and 1-HOCPh2-2-NEt2C6H4 (7), and the
2-phenylaminoalkyl-dimethylaminobenzene derivatives 1-NMe2-2-NH(Ph)C(H)PhC6H4 (3) and 1-NMe2-2-NH(Ph)C(H)PhCH2C6H4 (5).
Compounds 1–7 were characterized spectroscopically (NMR, IR, MS) and by crystal structure determination.
q 2003 Elsevier Ltd. All rights reserved.
1. Introduction
were previously reported but not structurally characterized.
A modified procedure for the synthesis of 1 is reported.
Organolithium compounds are very versatile reagents in
organic and organometallic chemistry.1 The use of nitrogen
as a neighboring heteroatom to effect selective metalation
with n-butyllithium has been investigated,2–4 and the
reaction of the ortho-metalation product with ketones4–11
has already been described. ortho-Lithiation is, however,
not restricted to compounds containing nitrogen donor
atoms; other directing groups are also frequently encoun-
tered.12 Here we report the reaction of N,N-dimethyl-o-
toluidine, N,N-dimethylaniline, and N,N-diethylaniline with
n-butyllithium-tmeda in diethyl ether–hexane solution to
give o-lithioarylamines, which react in situ with benzophe-
none, dicyclohexyl ketone, bezaldehyde, and Ph(H)CvNPh
to form the corresponding (2-dialkylaminophenyl)alcohols
1-HOCPh2-2-NMe2C6H4 (1), 1-HOCCy2-2-NMe2C6H4 (2),
1-HOCPh2CH2-2-NMe2C6H4 (4), 1-HOC(H)PhCH2-2-
NMe2C6H4 (6), and 1-HOCPh2-2-NEt2C6H4 (7), and the
2-phenylaminoalkyl-dimethylaminobenzene derivatives
1-NMe2-2-NH(Ph)C(H)PhC6H4 (3) and 1-NMe2-2-
NH(Ph)C(H)PhCH2C6H4 (5). Compounds 1–7 were
characterized spectroscopically (NMR, IR, MS), and crystal
structures were determined for 1–7. Compounds 111 and 410
The Li derivatives of compounds 1–713 are useful starting
materials for main group and transition metal compounds,14
in which they act as hemilabile O,N- or N,N-chelating
ligands forming six- and seven-membered chelate rings.
2. Results and discussion
2.1. Synthesis
N,N-Dimethylaniline and N,N-diethylaniline were treated
with n-butyllithium in diethyl ether–hexane solution for one
week, but the yields of the ortho-lithiated products were
low. It was anticipated that N,N-dimethyl-o-toluidine should
undergo metalation with n-butyllithium at the 2-methyl
position, since the 2-methyl protons are more acidic than the
ring protons, and a five-membered cyclic intermediate could
be formed.10 We found that when N,N-dimethyl-o-toluidine,
N,N-dimethylaniline, and N,N-diethylaniline were treated
with n-butyllithium-tmeda in diethyl ether–hexane, not
only did metalation occur much more rapidly (2–3 h) and
selectively than with n-butyllithium alone, but the overall
yields were also increased. The lithium reagents 1-Li-2-
NR2C6H4 (R¼Me, Et) and 1-LiCH2-2-NMe2C6H4 were
treated with various electrophilic compounds, followed
by hydrolytic acidic workup to form the corresponding
Keywords: (2-Dialkylaminophenyl)methanols and -ethanols; 2-
Phenylaminoalkyl-dimethylaminobenzene derivatives.
*
Corresponding author. Tel.: þ49-341-9736151; fax: þ49-341-9739319;
e-mail address: hey@rz.uni-leipzig.de
Crystal structure determination.
†
0040–4020/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2003.11.022

334
H. T. Al-Masri et al. / Tetrahedron 60 (2004) 333–339
Scheme 1. Preparation of 1–7.
(2-dialkylaminophenyl)alcohols and 2-phenylaminoalkyl-
dimethylaminobenzene derivatives, as illustrated in
Scheme 1.
The NMe2-substituted compounds 1–6 were obtained in
60–70% yield, while the NEt2 derivative 7 was obtained in
only 20% yield.
2.2. Spectroscopic properties
2.2.1. IR spectra. The infrared spectra of 1, 2, 4, 6, and 7
showed broad hydroxyl bands in the 3450–3290 cm21
region. The spectrum of the 2-phenylaminoalkyl-dimethyl-
aminobenzene derivatives 3 and 5 exhibited sharp peaks
around 3290 cm21 and 1600–1540 cm21 for secondary
amino groups.15 These bands have their origin in strong
O–H· · ·N and N–H· · ·N intramolecular hydrogen bonds.
The presence of both acidic and basic groups in these
molecules makes this type of hydrogen bonding the most
favorable interaction. In many amino acids such intra-
molecular interaction between the acidic and the basic
groups in the form þN–H· · ·O2 was found in the solid
state.16
The IR spectrum of each compound showed one sharp peak
in the range of 770–690 cm21, indicative of an ortho-
disubstituted aromatic ring and ascribable to the four
adjacent aromatic hydrogen atoms.17 In addition to the
peaks mentioned above, the IR spectrum of each compound,
except for 7, showed a strong peak in the range of 855–
837 cm21, which can be attributed to the unaltered
dimethylaminomethyl group.16 Absorptions in the range
of 1042–1010, 690–670 and 760–750 cm21 are observed
for the phenyl groups.
2.2.2. Mass spectrometry. The mass spectra of 1–7
showed parent-ion peaks at m/z 302.9 (1), 314.9 (2), 302.4
(3), 316.8 (4), 316.0 (5), 241.3 (6) and 331.3 (7), which
agree with the calculated distribution pattern.
1
1
2.2.3. H and 13C NMR spectra. In the H NMR spectra,
the most noticeable signal is that due to the N(CH3)2
protons, which give rise to a singlet for each compound in
the range 2.38–2.78 ppm. The resonances corresponding to
the benzylic protons are observed at 3.74 (4) as a singlet,
and at 2.93, 4.32 (5) and 3.10, 4.94 ppm (6) as doublets. The
singlet at 4.39 (3) and the triplets at 3.20 (5) and 3.21 ppm

H. T. Al-Masri et al. / Tetrahedron 60 (2004) 333–339
335
˚
Table 2. Selected bond lengths (A) and angles (deg) for 4–6
4a
4b
1.447(3)
5
6
C(3)–N(1)
C(3)–C(8)
C(8)–C(9)
C(9)–C(10)
C(10)–O or C(10)–N(2)
N(1)–C(3)–C(8)
C(3)–C(8)–C(9)
C(8)–C(9)–C(10)
C(9)–C(10)–O or C(9)–C(10)–N(2)
C(3)–N(1)–C
1.449(2)
1.403(2)
1.517(2)
1.547(2)
1.435(2)
118.4(2)
123.1(2)
113.9(2)
109.7(2)
114.8(2), 112.0(2)
109.5(2)
108.7
1.427(2)
1.408(2)
1.508(3)
1.540(3)
1.447(2)
118.6(2)
122.7(2)
112.9(2)
108.3(2)
1.435(2)
1.398(2)
1.518(2)
1.533(2)
1.472(2)
118.8(2)
122.7(2)
114.2(2)
110.8(2)
1.406(2)
1.512(2)
1.546(2)
1.435(2)
118.4(2)
122.5(2)
113.7(2)
109.9(2)
115.0(2), 112.6(2)
110.0(2)
106.6
114.6(2), 112.1(2)
111.3(3)
114.4(2)
113.5(2), 111.9(2)
110.0(2)
110.4(2)
C(1)–N(1)–C(2)
C(10)–O(1)–H or C(10)–N(2)–H
(6) are characteristic for an X–CH proton (XvO, N), while
a signal at 6.17 ppm (3) or 6.10 ppm (5) is indicative of an
NH proton. Also, a signal for the OH proton is observed at
9.80 (1), 10.69 (2), 8.55 (4), 7.02 (6), and 10.50 ppm (7). A
quartet at 2.61, 2.77 and a triplet at 0.92 ppm (7) are
characteristic for NCH2CH3 protons. The resonances
corresponding to the cyclohexyl protons are observed at
1.10–1.80 ppm (2) as broad peaks. The aromatic rings of
each compound give rise to the characteristic proton signals
in the expected range of 6.70–7.42 ppm.
6, and 7 is the intramolecular O(1)–H· · ·N(1) or N(2)–
H· · ·N(1) hydrogen bond (Table 3), which results in six-
membered C3OH· · ·N rings in 1, 2, and 7 (the atoms N(1)–
C(3)–C(8)–C(9) are coplanar), and seven-membered
C4XH· · ·N (XvO(1), N(2)) rings in 4–6 (the atoms
N(1)–C(3)–C(8)–C(9)–C(10) are coplanar). No intra-
molecular N(2)–H· · ·N(1) or intermolecular hydrogen
bond is observed in 3.
The intramolecular O(1)–H· · ·N(1) hydrogen bonds of 1, 2,
4, 6, and 7 are stronger than the intramolecular N–H· · ·O
hydrogen bonds reported for (p-CH3C6H4)2BOCH2CH2-
NH2 and (C6H5)2BOCH2CH2NH2 (N· · ·O¼2.982(2) or
The 13C NMR spectra of 1–6 reveal signals of the N(CH3)2
carbon atoms at 45.4–47.3 ppm. Singlets at 76.5–84.6 ppm
are assigned to the C–O carbon atom in 1, 2, 4, 6, and 7.
Signals for the methylene carbon atoms are observed at 45.0
(4), 42.0 (5), and 44.6 ppm (6), while the resonances at 56.2
(3), 62.1 (5), and 65.9 ppm (6) are characteristic of X–CH
carbon atoms (XvO, N). The resonances at 12.5 and
49.1 ppm (7) are characteristic for NCH2CH3 carbon atoms.
The resonances of the aromatic carbon atoms (111.8–
154.0 ppm) and the cyclohexyl groups (27.4–47.1 ppm) are
in the expected ranges.
18
˚
2.896(2) A),
as well as those reported for related
2.3. Molecular structures of 1–7
Colorless crystals of 1–7 were obtained as described in the
experimental section. Selected interatomic distances and
angles are collected in Tables 1 and 2. The molecular
structures are depicted in Figures 1–7.
Figure 2. Molecular structure of 2.
The common feature of the molecular structures of 1, 2, 4, 5,
Figure 1. Molecular structure of 1.
Figure 3. Molecular structure of 3.

336
H. T. Al-Masri et al. / Tetrahedron 60 (2004) 333–339
Figure 6. Molecular sturcture of 6 (disordered COH group is shown).
Figure 7. Molecular structure of 7.
Figure 4. Molecular structure of 4a and 4b.
five- and six-membered rings (N–H· · ·O: N· · ·O¼2.702(2)–
˚
˚
2.752(3) A, O–H· · ·O: O· · ·O¼2.674(2)–2.703(3) A, and
19
˚
N–H·· ·N: N· · ·N¼3.024(4)–3.054(2) A).
The intramolecular N(2)–H· · ·N(1) hydrogen bond of 5 is
weaker than intramolecular N–H· · ·N, N–H· · ·O, and
O–H· · ·O hydrogen bonds reported previously.19 Unlike
compounds 1, 2, and 7, in which the O–H moiety forms an
intramolecular hydrogen bond with a nitrogen atom, the
N(2)–H proton in 3 is not involved in any hydrogen bonding
˚
(N· · ·N¼4.134 A). This is presumably the result of steric
blocking of the N(2)–H proton by the bulky phenyl groups.
The N· · ·N distance for the N(2)–H· · ·N(1) interaction in 5
is longer than those observed for N–H· · ·N hydrogen bonds
˚
in monocationic compounds, which range up to 2.626 A for
linear systems20 and comparable to the mean value of the
˚
2.949 A for noncationic N–H· · ·N hydrogen bonds in
Figure 5. Molecular structure of 5.
crystalline organic compounds.21 The O(1)–H· · ·N(1)
Table 3. Hydrogen bond data for 1, 2, 4a, 4b, 5, 6, and 7
O(1)–H or N(2)–H
N(1)· · ·H
O(1)· · ·N(1) or N(2)· · ·N(1)
O(1)–H· · ·N(1) or N(2)–H· · ·N(1)
1
2
4a
4b
5
0.95(2)
0.92(2)
0.94a
1.82(2)
1.73(2)
1.83a
2.659(2)
2.591(1)
2.757(2)
2.747(2)
3.019(2)
2.686(6)
2.663(2)
146(2)
155(2)
167a
0.94a
1.82a
166a
0.84(2)
0.89(3)
0.91(2)
2.23(2)
1.80(3)
1.83(2)
155(2)
168(3)
151(2)
6
7
a
No standard deviation given as OH proton is in a calculated position.

H. T. Al-Masri et al. / Tetrahedron 60 (2004) 333–339
337
hydrogen bonds in 1, 2, and 7 are stronger than the
X–H· · ·N(1) (XvO(1), N(2)) hydrogen bonds in 4, 5, and 6,
consistent with the fact that increasing the ring size from
six- to seven-membered weakens the O(1)–H· · ·N(1)
hydrogen bond. Also, the O(1)–H· · ·N(1) hydrogen bond
is stronger than the N(2)–H· · ·N(1) hydrogen bond.
(0.082 mol) of benzophenone in 40 ml of anhydrous diethyl
ether was added dropwise to the reaction mixture and with
stirring over 30 min. The resulting deep green solution was
stirred for an additional 0.5 h and then poured into a
vigorously stirred solution of 13 g (0.22 mol) glacial acetic
acid in 40 ml of diethyl ether. The solution was stirred
overnight at room temperature. Then the solution was
successively extracted with 50 ml of distilled water and with
five 50 ml portions of aqueous 5% hydrochloric acid. The
aqueous extracts were combined and made alkaline with
aqueous 10% sodium hydroxide.
The structural data of the six-membered C3OH· · ·N rings in
1, 2, 3 and 7 (Table 1) show the expected bond lengths and
angles.19–21 Only in 1, 2, and 7 the C(8)–C(9)–O(1) bond
angles (109.9–112.38) are slightly larger, and the C(9)–
O(1)–H bond angles (104–1078) slightly smaller, than
expected, owing to the formation of intramolecular O(1)–
H· · ·N(1) hydrogen bonds.
The alkaline aqueous mixture was heated to boiling and
maintained at this temperature until the escaping vapor was
no longer basic to moistened pH paper. The mixture was
then cooled, and the white solid product which separated
was collected on a Buchner funnel and washed with three
20 ml portions of water. The crude product was recrystal-
lized from hexane/ethyl acetate solution at 20 8C to give the
product as colorless crystals in 70% yield. Mp 177–178 8C.
1H NMR (CDCl3, d/ppm): 2.38 (s, 6H, N(CH3)2), 6.70–7.38
(m, 14H, C6H4 and C6H5), 9.80 (s, 1H, OH). 13C NMR
(CDCl3, d/ppm): 46.3 (s, N(CH3)2), 83.6 (s, C–O), 124.2 (s,
C6 in C6H4), 125.8 (s, C4 in C6H4), 126.4 (s, C3 in C6H4),
127.5 (s, C5 in C6H4), 128.3 (s, p-C in C6H5), 128.9 (s, o-C
in C6H5), 131.1 (s, m-C in C6H5), 143.7 (s, C2 in C6H4),
148.3 (s, C1 in C6H4), 152.8 (s, ipso-C in C6H5). IR (KBr):
3423–2800 br., 1989 w, 1600 w, 1597 w, 1546 vs, 1392 vs,
1313 s, 1267 vs, 1205 s, 1166 s, 1154 vs, 1078 vs, 1051 vs,
1010 vs, 986 s, 969 s, 962 vs, 907 vs, 876 vs, 848 s, 771 s,
703 s, 587 s, 524 m, 516 m, 496 s, 442 m, 414 m cm21. MS:
m/z 302.9 (68%, Mþ), 225.9 (65%, Mþ2Ph), 209.8 (94%,
Mþ2Ph–OH), 193.8 (20%, Mþ2Ph–OH–CH3), 164.9
(30%, Mþ2Ph–OH–N(CH3)2), 90.9 (100%, C7Hþ7 ), 76.9
(86%, C6Hþ5 ), 50.9 (20%, C4Hþ3 ). Found: C 84.0; H 7.65; N
4.37%. Calcd for C21H21NO: C 83.13; H 6.98; N 4.62%.
The structural data of compounds 4–6 with seven-
membered C4XH· · ·N (XvO(1), N(2)) rings (Table 2) are
as expected.19,20,21 Only the C(8)–C(9)–C(10) bond angle
is slightly larger (112.9–114.28) than expected. The C(3)–
C(8) distances in 1–7 agree with the mean literature value
22
˚
of 1.394 A.
The nitrogen atom N(1), which is bound to the aromatic
ring, has a distorted environment with large C(1)–N(1)–
C(2) (109.5–11.38) and C(3)–N(1)–C (113.5–115.08;
111.9–112.68) bond angles.
Compounds 3, 5 and 6 are obtained as racemic mixtures.
The molecular structure of 6 shows disorder of the (C)–O–H
and (C(10))–H groups (71.3% C–O(1)–H and 28.7% C–
O(1f)–H).
3. Experimental
3.1. General
Phenyl ring numbering scheme:
All experiments were carried out under purified dry
nitrogen. Solvents were dried and freshly distilled under
nitrogen. The NMR spectra were recorded with an
AVANCE DRX 400 spectrometer (Bruker). Infrared spectra
were recorded with a Perkin–Elmer System 2000 FT-IR
spectrometer between 4000 and 400 cm21 using KBr disks.
Elemental analyses were determined with a VARIO EL
(Heraeus). Melting points (Gallenkamp) are uncorrected.
Mass spectra were recorded with a MAT-8230 (EI-MS,
70 eV). Crystallographic data were collected with a
Siemens CCD (SMART) diffractometer. All observed
reflections were used for determination of the unit cell
parameters. Empirical absorption correction with
SADABS.23 The structures were solved by direct methods
(SHELXTL PLUS).24 H atoms were located by difference
maps and refined isotropically. Details concerning the
crystal structure determination are given in Table 4.
3.1.2. (2-Dimethylaminophenyl)dicyclohexylmethanol
(2). The reaction was carried out by the same procedure
as described for 1, except that 16.0 g (0.082 mol) of
dicyclohexyl ketone was used instead of benzophenone,
and that the colorless crystals were obtained from a
saturated hexane/benzene solution (5:1) at 0 8C in 70%
1
yield. Mp 160–165 8C. H NMR (CDCl3, d/ppm): 1.10–
1.80 (br., 22H, C6H11), 2.65 (s, 6H, N(CH3)2), 7.10–7.32
(m, 4H, C6H4), 10.69 (s, 1H, OH). 13C NMR (CDCl3, d/
ppm): 27.4 (s, C4 in C6H11), 27.5 (s, C3/C5 in C6H11), 28.6
(s, C2/C6 in C6H11), 47.1 (s, C1 in C6H11), 47.3 (s,
N(CH3)2), 84.6 (s, C–O), 123.7 (s, C6 in C6H4), 126.0 (s,
C4 in C6H4), 127.6 (s, C3 in C6H4), 128.6 (s, C5 in C6H4),
139.3 (s, C2 in C6H4), 154.0 (s, C1 in C6H4). IR (KBr): 2930
vs, 2850 vs, 2788 s, 1919 w, 1703 w, 1601 s, 1574 w, 1451 s,
1335 w, 1263 w, 1187 s, 1145 s, 1101 s, 1043 s, 993 s, 932 s,
3.1.1. (2-Dimethylaminophenyl)diphenylmethanol (1). A
dry 250 ml two-necked flask was filled with 10 g
(0.082 mol) of N,N-dimethylaniline, 120 ml of anhydrous
diethyl ether and 12.37 ml of tmeda and the solution was
stirred under nitrogen atmosphere. 60 ml of a 1.5 M solution
of n-butyllithium in hexane was added at 278 8C. The
solution was allowed to warm to room temperature, stirred
for 2 h and refluxed for 2 h. Then a solution of 14.9 g
851 w, 892 s, 827 s, 759 s, 716 s, 565 s, 517 m, 483 w cm21
MS: m/z 314.9 (6%, Mþ), 298.0 (10%, Mþ2OH), 232.8
.

338
H. T. Al-Masri et al. / Tetrahedron 60 (2004) 333–339
Table 4. Crystal data and structure refinement for 1–7
1
2
3
4
5
6
7
Formula
Mr
C
21H21NO
C21H33NO
315.48
218(2)
Triclinic
¯
P 1
9.929(1)
10.330(1)
10.926(1)
101.609(2)
101.094(2)
114.919(2)
945.9(2)
2
1.108
348
0.066
6226
4293
0.0158
341
0.0434
0.1420
0.210
C21H22N2
302.41
223(2)
Monoclinic
C2/c
26.774(3)
9.3063(9)
18.661(2)
90
132.950(1)
90
3403.3(6)
8
1.180
1296
0.069
11103
4202
0.0291
296
0.0384
0.0893
0.160
C22H23NO
317.41
223(2)
Orthorhombic
Pca21
17.765(1)
5.9999(3)
33.712(2)
90
90
90
3593.3(3)
8
1.173
1360
0.071
19386
7338
0.0232
433
0.0375
0.0994
0.162
C22H24N2
316.43
213(2)
Monoclinic
Cc
14.220(2)
13.679(2)
11.553(2)
90
125.227(2)
90
1835.7(5)
4
1.145
680
0.067
5639
3004
0.0217
313
0.0349
0.0821
0.108
C16H19NO
240.31
223(2)
Orthorhombic
Pbca
14.916(1)
8.1647(8)
22.681(2)
90
90
90
2762.2(5)
8
1.156
1032
0.072
16472
3439
0.0385
249
0.0512
0.1480
0.242
C23H25NO
331.44
213(2)
Orthorhombic
Pbca
8.532(1)
16.361(2)
27.735(4)
90
90
90
3871.5(9)
8
1.137
1424
0.069
23266
4614
0.0292
326
0.0467
0.1279
0.210
303.39
213(2)
Monoclinic
P21/n
8.856(2)
12.538(3)
15.556(3)
90
100.77(3)
90
1696.8(6)
4
1.188
648
0.072
10063
2647
0.0489
209
0.0431
0.0925
0.225
Temp (K)
Crystal system
Space group
˚
a (A)
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
3
˚
V (A )
Z
rcalcd (mg m23
F(000)
)
Abs coeff (mm21
No. of rflns coll.
)
No. of indep rflns
Rint
No. of params
R1 (I.2s(I))
wR2 (all data)
23
˚
(D/r)min (e A
)
23
˚
(D/r)max (e A
)
CCDC depos. no.
20.185
190705
20.184
190712
20.164
190708
20.152
190707
20.136
190711
20.140
190709
20.181
190710
(100%, Mþ2Cy), 214.7 (15%, Mþ2Cy–OH), 148.0 (8%,
Mþ22Cy), 132.4 (30%, Mþ22Cy–OH), 83.4 (10%, Cyþ),
54.9 (15%, C4Hþ7 ). Found: C 80.10; H 12.40; N 4.17%.
Calcd for C21H33NO: C 79.95; H 10.54; N 4.44%.
OH). 13C NMR (CDCl3, d/ppm): 45.0 (s, CH2), 45.4 (s,
N(CH3)2), 78.6 (s, C–O), 120.0 (s, C6 in C6H4), 125.0 (s,
C4 in C6H4), 126.2 (s, C3 in C6H4), 126.3 (s, C5 in C6H4),
128.4 (s, p-C in C6H5), 128.5 (s, o-C in C6H5), 133.2 (s, m-C
in C6H5), 133.5 (s, C2 in C6H4), 147.9 (s, C1 in C6H4), 151.8
(s, ipso-C in C6H5). IR (KBr): 3428 br., 3083 s, 3054 s, 3021
s, 2994 m, 2946 m, 2931 m, 2861 s, 2831 vs, 2801 s, 2784 s,
1948 w, 1597 w, 1580 vs, 1492 vs, 1474 s, 1460 s, 1446 vs,
1230 m, 1180 s, 1105 s, 1058 s, 1038 m, 955 s, 937 s, 862 s,
845 w, 786 s, 767 vs, 757 vs, 701 vs, 647 m, 608 s, 534 m
cm21. MS: m/z 316.8 (8%, Mþ), 299.8 (5%, Mþ2OH),
239.8 (9%, Mþ2Ph), 134.9 (100%, Mþ22Ph–2CH3), 90.9
(15%, C7Hþ7 ), 76.9 (25%, C6H5þ), 50.9 (6%, C4Hþ3 ). Found:
C 83.10; H 7.10; N 4.71%. Calcd for C22H23NO: C 83.24; H
7.30; N 4.41%.
3.1.3. 2-(Phenylamino-phenyl)methyl-dimethylamino-
benzene (3). The reaction was carried out by the same
procedure as described for 1, except that 14.9 g (0.082 mol)
of N-benzylidenaniline was used instead of benzophenone,
and that the colorless crystals were obtained from toluene/
hexane solution (1:3) at 20 8C in 65% yield. Mp 133–
1
135 8C. H NMR (CDCl3, d/ppm): 2.61 (s, 6H, N(CH3)2),
4.39 (s, 1H, CH), 6.17 (s, 1H, NH), 6.54–7.36 (m, 14, C6H4
and C6H5). 13C NMR (CDCl3, d/ppm): 45.5 (s, N(CH3)2),
56.2 (s, CH), 113.1 (s, C6 in C6H4), 117.2 (s, C4 in C6H4),
121.4 (s, C3 in C6H4), 124.3 (s, C5 in C6H4), 126.7 (s, p-C in
C6H5), 129.1 (s, o-C in C6H5), 138.9 (s, m-C in C6H5), 144.1
(s, C2 in C6H4), 147.6 (s, C1 in C6H4), 152.4 (s, ipso-C in
C6H5). IR (KBr): 3315 vs, 3100 m, 3080 m, 3000 s, 2920 m,
2900 m, 2840 s, 2820 m, 2785 vs, 1950 w, 1601 vs, 1583 vs,
1506 vs, 1448 vs, 1429 vs, 1351 s, 1314 vs, 1300 vs, 1266 s,
1183 vs, 1154 vs, 1047 s, 1027 m, 945 vs, 888 s, 840 vs, 744
vs, 730 vs, 695 vs, 585 m, 509 m cm21. MS: m/z 302.4
(50%, Mþ), 286.9 (10%, Mþ2NH), 209.9 (100%,
Mþ2Ph–NH), 193.9 (25%, Mþ2Ph–NH–CH3), 179.9
(8%, Mþ2Ph–NH–2CH3), 90.9 (64%, C7Hþ7 ), 76.9 (25%,
C6Hþ5 ), 50.9 (8%, C4Hþ3 ). Found: C 83.60; H 7.29; N 9.48%.
Calcd for C21H22N2: C 83.40; H 7.33; N 9.26%.
3.1.5. 2-(2-Phenylamino-2-phenyl)ethyl-dimethylamino-
benzene (5). The reaction was carried out by the same
procedure as described for 3, except that 11.1 g (0.082 mol)
of N,N-dimethyl-o-toluidine was used instead of N,N-
dimethylaniline, and that the colorless crystals were
obtained from toluene at 20 8C in 60% yield. Mp 145–
1
150 8C. H NMR (CDCl3, d/ppm): 2.78 (s, 6H, N(CH3)2),
3.20 (t, 3JH–H¼12 Hz, 1H, CH), 2.93 (d, 3JH–H¼12 Hz, 1H,
3
CH2), 4.32 (d, JH–H¼12 Hz, 1H, CH2), 6.10 (s, 1H, NH),
6.20–7.42 (m, 14H, C6H4 and C6H5). 13C NMR (CDCl3, d/
ppm): 42.0 (s, CH2), 46.1 (s, N(CH3)2), 62.1 (s, CH), 113.5
(s, C6 in C6H4), 116.8 (s, C4 in C6H4), 120.6 (s, C3 in
C6H4), 125.2 (s, C5 in C6H4), 127.5 (s, p-C in C6H5), 129.6
(s, o-C in C6H5), 135.2 (s, m-C in C6H5), 145.2 (s, C2 in
C6H4), 148.6 (s, C1 in C6H4), 153.5 (s, ipso-C in C6H5). IR
(KBr): 3290 vs, 3105 m, 3082 m, 2996 s, 2980 m, 2944 m,
2880 s, 2825 m, 2785 vs, 1960 w, 1600 vs, 1523 vs, 1490 vs,
1450 vs, 1435 vs, 1351 s, 1324 vs, 1293 vs, 1277 s, 1179 vs,
1154 vs, 1041 s, 1028 m, 940 vs, 845 vs, 774 s, 758 vs, 748
vs, 693 vs, 546 m, 527 m cm21. MS: m/z 316.0 (11%, Mþ),
223.9 (5%, Mþ2Ph–NH), 207.9 (5%, Mþ2Ph–NH–CH3),
3.1.4. 2-(2-Dimethylaminophenyl)-1,10-diphenylethanol
(4). Compound 4 was prepared as described in the
literature.10 The crude product was recrystallized from
hexane/ethyl acetate (4:1) solution at 20 8C to give the
product as colorless crystals in 70% yield. Mp 151–153 8C
(lit. 153–155 8C, from benzene/hexane).10 1H NMR
(CDCl3, d/ppm): 2.74 (s, 6H, N(CH3)2), 3.74 (s, 2H,
CH2), 6.49–7.40 (m, 14H, C6H4 and C6H5), 8.55 (s, 1H,

H. T. Al-Masri et al. / Tetrahedron 60 (2004) 333–339
339
192.9 (8%, Mþ2Ph–NH–2CH3), 180.9 (100%, Mþ2Ph–
References and notes
NH–NMe2), 90.9 (20%, C7Hþ7 ), 76.9 (38%, C6H5þ), 50.9
(18%, C4Hþ3 ). Found: C, 82.60; H, 8.13; N, 8.62%. Calcd for
C22H24N2: C, 83.50; H, 7.64; N, 8.85%.
1. (a) Williard, P. G. Comprehensive organic synthesis;
Pergamon: New York, 1991; Vol. 1, p 1. (b) Wakefield, B. J.
The chemistry of organolithium compounds; Pergamon: New
York, 1974. (c) Wakefield, B. J. Organolithium methods;
Academic: London, 1998.
3.1.6. 2-(2-Dimethylaminophenyl)-1-phenylethanol (6).
The reaction was carried out by the same procedure as
described for 4, except that 8.7 g (0.082 mol) of benzal-
dehyde instead of benzophenone was used and that the
colorless crystals were obtained from toluene at 25 8C in
70% yield. Mp 152–157 8C. 1H NMR (CDCl3, d/ppm): 2.78
(s, 6H, N(CH3)2), 3.21 (t, 3JH–H¼12 Hz, 1H, CH), 3.10 (d,
3JH–H¼12 Hz, 1H, CH2), 4.94 (d, 3JH–H¼12 Hz, 1H, CH2),
2. Jones, F. N.; Zinn, M. F.; Hauser, C. R. J. Org. Chem. 1963,
28, 663.
3. Puterbaugh, W. H.; Hauser, C. R. J. Am. Chem. Soc. 1963, 85,
2467.
4. Hay, J. V.; Harris, T. M. Org. Synth. 1973, 53, 56.
5. Wittig, G.; Merkle, W. Chem. Ber. 1942, 75, 1491.
6. Lepley, A. R.; Khan, W. A.; Giumanini, A. B.; Giumanini,
A. G. J. Org. Chem. 1966, 31, 2047.
7.02 (s, 1H, OH), 7.24–7.39 (m, 9H, C6H4 and C6H5). 13
C
NMR (CDCl3, d/ppm): 44.6 (s, CH2), 45.6 (s, N(CH3)2),
65.9 (s, CH), 76.5 (s, C–O), 120.8 (s, C6 in C6H4), 126.0 (s,
C4 in C6H4), 126.3 (s, C3 in C6H4), 127.6 (s, C5 in C6H4),
128.6 (s, p-C in C6H5), 129.2 (s, o-C in C6H5), 132.7 (s, m-C
in C6H5), 135.6 (s, C2 in C6H4), 146.1 (s, C1 in C6H4), 152.6
(s, ipso-C in C6H5). IR (KBr): 3366 br., 3060 w, 2940 m,
2859 m, 2829 m, 2786 s, 1951 w, 1597 s, 1580 vs, 1492 vs,
1451 vs, 1293 vs, 1267 vs, 1156 vs, 1100 vs, 1057 vs, 1005
vs, 939 s, 863 vs, 845 w, 759 vs, 699 vs, 635 s cm21. MS:
m/z 241.3 (18%, Mþ), 164.9 (5%, Mþ2Ph), 134.0 (100%,
Mþ2Ph–2CH3), 118.0 (22%, Mþ2Ph–NMe2), 90.9 (20%,
C7Hþ7 ), 76.9 (15%, C6H5þ), 50.9 (8%, C4Hþ3 ). Found: C
79.30; H 8.09; N 6.48%. Calcd for C16H19NO: C 79.62; H
7.87; N 5.81%.
7. Jones, F. N.; Vaulx, R. L.; Hauser, C. R. J. Org. Chem. 1963,
28, 3461.
8. Klein, K. P.; Hauser, C. R. J. Org. Chem. 1967, 32, 1479.
9. Jones, F. N.; Hauser, C. R. J. Org. Chem. 1962, 27, 4389.
10. Ludt, R. E.; Crowther, G. P.; Hauser, C. R. J. Org. Chem.
1970, 35, 1288.
11. Giumanini, A. G.; Giumanini, A. B.; Lepley, A. R. Chim. Ind.
(Milan) 1969, 51, 2.
´
12. (a) Bauer, W.; v. Rague Schleyer, P. J. Am. Chem. Soc. 1989,
´
111, 7191. (b) Saa, J. M.; Martorell, G.; Frontera, A. J. Org.
Chem. 1996, 61, 5194. (c) Rennels, R. A.; Maliakal, A. J.;
Collum, D. B. J. Am. Chem. Soc. 1998, 120, 421. (d) Clark,
R. D.; Jahangir, A. Organic reactions; Paquette, L. A., Ed.;
1995; Vol. 47, Chapter 1.
3.1.7. (2-Diethylaminophenyl)diphenylmethanol (7). The
reaction was carried out by the same procedure as described
for 1, except that 12.5 g (0.082 mol) of N,N-diethylaniline
was used instead of N,N-dimethylaniline and that the
colorless crystals were obtained from diethyl ether at
13. (a) Al-Masri, H. T.; Sieler, J.; Hey-Hawkins, E. Appl.
Organomet. Chem. 2003, 17, 63. (b) Al-Masri, H. T.; Sieler
J.; Hey-Hawkins, E. Appl. Organomet. Chem. 2003, 17, 641.
14. Al-Masri, H. T. PhD Thesis, Leipzig University, 2003.
15. Agashe, M. S.; Jose, C. I. J. Chem. Soc., Faraday Trans. 2
1977, 73, 1232.
1
210 8C in 20% yield. Mp 165–170 8C. H NMR (CDCl3,
3
d/ppm): 0.92 (t, JH–H¼8 Hz, 6H, N(CH2CH3)2), 2.61 (q,
3JH–H¼8 Hz, 2H, N(CH2CH3)2), 2.77 (q, 3JH–H¼8 Hz, 2H,
N(CH2CH3)2), 6.75–7.29 (m, 14H, C6H4 and C6H5), 10.50
(s, 1H, OH). 13C NMR (CDCl3, d/ppm): 12.5 (s,
N(CH2CH3)2), 49.1 (s, N(CH2CH3)2), 83.3 (s, C–O),
111.8 (s, C6 in C6H4), 115.4 (s, C4 in C6H4), 124.4 (s, C3
in C6H4), 124.9 (s, C5 in C6H4), 126.8 (s, p-C in C6H5),
128.3 (s, o-C in C6H5), 132.1 (s, m-C in C6H5), 144.7 (s, C2
in C6H4), 146.0 (s, C1 in C6H4), 148.1 (s, ipso-C in C6H5).
IR (KBr): 3060–2845 br., 1951 w, 1596 s, 1567 w, 1427 vs,
1385 vs, 1361 s, 1295 s, 1218 s, 1161 vs, 1115 vs, 1102 s,
1027 vs, 938 s, 833 vs, 759 vs, 699 vs, 636 vs, 596 s, 564 m,
523 m, 490 m, 452 m cm21. MS: m/z 331.3 (34%, Mþ),
316.2 (15%, Mþ2CH3), 298.2 (5%, Mþ2CH3–OH), 254.2
(45%, Mþ2Ph), 238.1 (47%, Mþ2Ph–CH3), 210.2 (15%,
16. Agashe, M. S.; Jose, C. I. J. Chem. Soc., Faraday Trans. 2
1977, 73, 1227.
17. Musso, H.; Sandrock, G. Chem. Ber. 1964, 97, 2076.
18. Rettig, S. J.; Trotter, J. Can. J. Chem. 1976, 54, 3130.
19. Kliegel, W.; Lubkowitz, G.; Rettig, S. J.; Trotter, J. Can.
J. Chem. 1992, 70, 2033.
20. Staab, H. A.; Saupe, T. Angew. Chem. 1988, 100, 895.
21. Saiz, A. L. L.; Force-Force, C. J. Mol. Struct. 1990, 238, 367.
22. Rettig, S. J.; Trotter, J. Can. J. Chem. 1973, 51, 1288.
23. Sheldrick, G. M. SADABS—a Program for Empirical
¨
Absorption Correction, Gottingen, 1998.
24. SHELXTL PLUS, XS: Program for Crystal Structure Solution,
XL: Program for Crystal Structure Determination, XP:
Interactiv Molecular Graphics; Siemens Analyt. X-ray Inst.
Inc., 1990.
Mþ2Ph–CH3–Et),
165.0
(13%,
Mþ2Ph–OH–
N(CH2CH3)2), 76.9 (64%, C6Hþ5 ), 50.9 (20%, C4H3þ).
Found: C, 82.40; H, 7.54; N, 3.99%. Calcd for C23H25NO:
C, 83.34; H, 7.60; N, 4.23%.