New strategy to the synthesis of (N → B) phenyl[N-alkyliminodiacetate-O,O′,N]boranes: The crystal structure of (N → B) phenyl[N-benzyliminodiacetate-O,O′,N]borane, (N → B)phenyl[N-(4-methyl)benzyliminodiacetate-O,O′,N]borane and (N → B) phenyl[N-phenacyli

Article abstract of DOI:10.1016/j.poly.2009.05.043

A new, mild and friendly method for the synthesis of (N → B) phenyl[N-alkyliminodiacetate-O,O′,N]boranes 2-7 is reported. All compounds were identified by ¹H, ¹¹B, ¹³C NMR and their high resolution mass spectra (HRMS) are

Full text of DOI:10.1016/j.poly.2009.05.043

Polyhedron 28 (2009) 2771–2775
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
New strategy to the synthesis of (N ? B) phenyl[N-alkyliminodiacetate-O,O0,N]-
boranes: The crystal structure of (N ? B) phenyl[N-benzyliminodiacetate-O,O0,N]-
borane, (N ? B)phenyl[N-(4-methyl)benzyliminodiacetate-O,O0,N]borane and
(N ? B) phenyl[N-phenacyliminodiacetate-O,O0,N]borane
*
Teresa Mancilla Percino , Roxana Magaly Flores Ancona, Marisol López Martínez
Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, 07000 México D.F., México
a r t i c l e i n f o
a b s t r a c t
Article history:
A
new, mild and friendly method for the synthesis of (N ? B) phenyl[N-alkyliminodiacetate-
O,O0,N]boranes 2–7 is reported. All compounds were identified by 1H, 11B, 13C NMR and their high reso-
lution mass spectra (HRMS) are reported. The structure of the compounds 2, 4 and 5 were established by
single crystal X-ray. Compounds 2 and 4 crystallized with two independent molecules 2A, 2B and 4A, 4B,
respectively in the asymmetric unit. These molecular structures established the bicyclic structure show-
ing a N ? B bond length of 1.666 (2) Å for 2A, 1.675 (2) Å for 2B, 1.675 (3) Å for 4A, 1.663 (3) Å for 4B and
1.679 (2) Å for 5, as well as different torsion angles of the junction, 28.70 (2)° (C11–B1–N6–C17) for 2A,
21.50 (2)° (C11a–B1a–N6a–C17a) for 2B, 25.76 (0.26)° (C11–B1–N6–C17) for 4A, 21.96 (0.28)° (C11a–
B1a–N6a–C17a) for 4B and ꢀ29.22 (0.20)° (C5–N1–B1–C13) for 5.
Received 30 December 2008
Accepted 20 May 2009
Available online 27 May 2009
Keywords:
Boron heterocycles
N-alkyiminodiacetateboranes
N-alkylation
X-ray
Spectroscopy
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
sis of (N ? B) phenyl[N-alkyliminodiacetate-O,O0,N]boranes 2–7,
by the reaction of boron heterocycle 1 with potassium bicarbonate,
Since the past four decades boron heterocycles derived from
amino acids have shown a potential use for biological studies,
mainly phenyl derivatives exhibit cytotoxic activity [1–5] and have
application in boron neutron capture therapy (BNCT) for the treat-
ment of brain tumors [6,7] and melanomas [8]. The chemistry of
boron iminodiacetic derivatives has been little studied [9–11],
which could be precursors of the new ligands potentially useful
for biological studies [12,13]. We have been interested in the
synthesis, characterization, structural analysis and reactivity of
boron heterocycles derived from hydroxyaminoacids, iminodiace-
tic acids and N-substitutedimino- and aminodiacetic acids
[9–11,14–21]. We have reported that (N ? B) phenyl[iminodiace-
tate-O,O0,N]borane 1 has a rigid bicyclic structure due to strong
intramolecular N ? B coordination bond, as well as hydrolytically
stable [14] and also its N-alkylation with lithium 2,6-dimethylpi-
peridide and lithium 2,2,6,6-tetramethylpiperidide as bulky bases
and alkyl halides under nitrogen atmosphere, the yields were be-
tween 39% and 33% [10,11]. Our current interest in the reactivity
of (N ? B) phenyl[iminodiacetate-O,O0,N]borane 1 to find a new
methods to obtain its N-alkyl derivatives prompted us to extend
these investigations to prepare them under friendly reaction condi-
tions and improve the yield. Thus, this article describes the synthe-
KHCO3, which is a soft base and alkyl halides under reflux of a mix-
ture of acetonitrile/benzene (80/20) or acetonitrile (Fig. 1). This
new method does not need anhydride conditions as we used pre-
viously [10,11]. All compounds were identified by 1H, 13C and 11B
NMR; their spectra are according with those data previously re-
ported by us [10,11]. While, their high resolution mass spectra
(HRMS) are reported. The structure of compounds 2, 4 and 5 were
further established by a single crystal X-ray diffraction study.
2. Results and discussion
(N ? B) phenyl[iminodiacetate-O,O0,N]borane 1 is character-
ized to have a rigid bicyclic structure due to a strong intramolecu-
lar nitrogen-boro coordination, and to be highly hydrolytically
stable [14]. These characteristics, and the fact that NH group has
acid property, led us to study its reactivity under different condi-
tions to obtain its N-alkylboron heterocycles [9–11], which have
been hydrolyzed to the corresponding N-substituted iminodiacetic
acids [10,11], as interesting biological ligands [13]. However, the
N-alkylboron heterocycles have been obtained with low yields,
probably caused in the purification of the compounds for the use
of lithium 2,6-dimethylpiperidide and lithium 2,2,6,6-tetrame-
thylpiperidide as bases. We attempt to investigate if the use of a
soft base as KHCO3 could react with the NH group of (N ? B)
* Corresponding author. Tel.: +52 5 57 47 33 96; fax: +52 5 57 47 33 89.
E-mail address: tmancill@cinvestav.mx (T.M. Percino).
0277-5387/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2009.05.043

2772
T.M. Percino et al. / Polyhedron 28 (2009) 2771–2775
phenyl[iminodiacetate-O,O0,N]borane 1 and carry out a substitu-
tion nucleophilic reaction with benzyl bromide a, 3-methylbenzyl
bromide b, 4-methylbenzyl bromide c, phenacyl bromide d, 2-bro-
cleus, since they lie in the range reported previously for analogous
boron heterocycles [9–11,13–16,19]. All compounds exhibit the
expected 13C NMR spectra. Suitable crystals of 2, 4 and 5 were ob-
tained for X-ray analysis and an ORTEP view and crystallographic
numbering of 2, 4 and 5 are giving in Figs. 2–4, respectively. Se-
lected bond distance and torsion angles are listed in Tables 1–3.
In general the bond distances are within the values characteristic
of analogous compounds [17,19]. Compounds 2 and 4 crystallized
with two independent molecules 2A, 2B and 4A, 4B, respectively
and 5 exhibits only one. The conformations of the two five member
ring in all molecules are different and not planar, as indicated by
the torsion angles values (Tables 1–3). This can be due in part to
mo-40-chloroacetophenone
e
and 2-bromo-40-phenylacetophe-
none f, under reflux of acetonitrile/benzene (80/20) or
acetonitrile to obtain (N ? B) phenyl[N-alkyliminodiacetate-
O,O0,N]boranes 2–7, (Fig. 1). Effectively, the yields are between
40% and 80%. 1H, 13C and 11B NMR and their high resolution mass
spectra (HRMS) data of the compounds 2–7 are giving in the exper-
imental part. Their 1H NMR spectra clearly show the AB coupling
patterns for the diastereotopic CH2COO protons, which indicates
the presence of the intramolecular N ? B coordination bond. The
d(11B) values confirm the tetrahedral environment of the boron nu-
the following intermolecular interactions:
O9A. . .H5A 2.288,
O
O
1
2
O
O
O
m
o
KHCO3 / RX
p
H
N
B
R
N
B
CH3CN/benzene or
CH3CN
reflux
O
O
O
1
2-7
10
CH3
5
9
6
5
9
6
8
5
9
6
3
H2C
3
H2C
10
3
H2C
4
7
4
4
4
:
2
:
CH3
7
3
:
7
8
8
O
O
O
11
6
7
10
6
7
6
7
3
3
3
5
4
5
5
4
4
8
8 9
12
7
:
5
:
6
:
H2C-C
H2C-C
H2C-C
Cl
8
9
9
10
10
Fig. 1. Synthesis of boron heterocycles 2–7.
Fig. 2. Molecular structure of C17H16BNO4 and crystallographic numbering scheme of molecule 2A.

T.M. Percino et al. / Polyhedron 28 (2009) 2771–2775
2773
Fig. 3. Molecular structure of C18H18BNO4 and crystallographic numbering scheme of molecule 4A.
O9. . .H5A2 2.522 and O10. . .H16A 2.544 Å for 2, O4. . ..H5A1 2.371,
4A. . ..H17D 2.377, O9. . ..H17B 2.450 and O9A. . ..H7B 2.458 Å for 4
O
and O2. . ..H14 2.5646, O5. . ..H3B 2.4824, O5. . ..H2B 2.5818 and
O5. . ..H12 2.4867 Å for 5, which are significantly shorter than the
sum of the van der Waals radii of oxygen and hydrogen (2.70 Å)
[22]. On the another hand, the Ph–B and N–R groups are bent away
from the N ? B bond, as indicated by the bond angle values C11
–
B1–N6 of 117.11 (13)° and C17–N6–B1 of 112.90 (12)° for 2A,
C11a–B1a–N6a of 115.42 (15)° and C17a–N6a–B1a of 112.51 (13)° for
2B, C11–B1–N6 of 115.89 (19)° and C17–N6–B1 of 114.29 (16)° for
4A, C11a–B1a–N6a of 115.9 (2)° and C17a–N6a–B1a of 115.42 (17)°
for 4B, C13–B1–N1 of 117.58 (14)° and C5–N1–B1 of 113.39 (12)°
for 5. The molecular structures of the compounds 2, 4 and 5 estab-
lish the bicyclic structures showing a N ? B of bond length of 1.666
(2) Å for 2A, 1.675 (2) Å for 2B, 1.675 (3) Å for 4A, 1.663 (3) Å for 4B
and 1.679 (2) Å for 5, the values being comparable to the N ? B
bond length in analogous compounds [17,19].
Fig. 4. Molecular structure of C18H16BNO5 and crystallographic numbering scheme
of molecule 5.
Table 1
Table 2
Bond distances selected (Å) and torsion angles (°) for C17H16BNO4 (2).
Bond distances selected (Å) and torsion angles (°) for C18H18BN04 (4).
Molecule 2A
Molecule 2B
Molecule 4A
Molecule 4B
Bond distances (Å)
O2–B1
O10–B1
N6–B1
O2–C3
O10–C8
O4–C3
O9–C8
C3–C5
C7–C8
N6–C5
Bond distances (Å)
O2–B1
O10–B1
N6–B1
O2–C3
C3–C5
N6–C5
N6–C7
C7–C8
O10–C8
O4–C3
1.486 (2)
1.460 (2)
1.666 (2)
1.332 (2)
1.326 (2)
1.201 (2)
1.202 (2)
1.510(2)
1.506 (2)
1.486 (2)
1.494 (2)
1.587 (3)
1.511 (3)
O2a–B1a
O10a–B1a
N6a–B1a
O2a–C3a
O10a–C8a
O4a–C3a
O9a–C8a
C3a–C5a
C7a–C8a
N6a–C5a
N6a–C7a
B1a–C11a
N6a–Cl7a
1.484 (2)
1.467 (2)
1.675 (2)
1.322 (3)
1.329 (2)
1.201 (2)
1.203 (2)
1.508 (3)
1.494 (3)
1.484 (2)
1.582 (3)
1.587 (3)
1.516 (3)
1.489 (3)
1.454 (3)
1.675 (3)
1.319 (3)
1.508 (3)
1.484 (3)
1.498 (3)
1.503 (3)
1.320 (3)
1.202 (2)
1.196 (3)
O2a–B1
1.466 (3)
1.482 (3)
1.663 (3)
1.311 (3)
1.488 (4)
1.495 (3)
1.484 (3)
1.506 (4)
1.315 (3)
1.205 (3)
1.206 (3)
O10a–B1a
N6a–B1a
O2a–C4a
C4a–C5a
N6a–C5a
N6a–C7a
C7a–C8a
O10a–C8a
O4a–C4a
O9b–C8b
N6–C7
B1–C11
N6–C17
O9–C8
Torsion angles (°)
N6–B1–O2–C3
C5–C3–O2–B1
O2–C3–C5–N6
C3–C5–N6–B1
O2–B1–N6–C5
N6–B1–O10–C8
C7–C8–O10–B1
N6–C7–C8–O10
C8–C7–N6–B1
O10–B1–N6–C7
C11–B1–N6–C17
C12–C11–B1–N6
ꢀ20.70 (0.23)
9.01 (0.26)
9.17 (0.25)
N6a–B1a–O2a–C4a
B1a–O2a–C4a–C5a
O2a–C4a–C5a–N6a
C4a–C5a–N6a–B1a
O2a–B1a–N6a–C5a
N6a–B1a–O10a–C8a
C7a–C8a–O10a–B1a
N6a–C7a–C8a–O10a
C8a–C7a–N6a–B1a
O10a–B1a–N6a–C7a
C11a–B1a–N6a–C17a
C12a–C11a–B1a–N6a
ꢀ18.81 (0.26)
9.91 (0.30)
5.11 (0.29)
Torsion angles (°)
N6–B1–O2–C3
C5–C3–O2–B1
O2–C3–C5–N6
C3–C5–N6–B1
O2–B1–N6–C5
N6–B1–O10–C8
C7–C8–O10–B1
N6–C7–C8–O10
C8–C7–N6–B1
O10–B1–N6–C7
C11–B1–N6–C17
ꢀ15.75(0.17)
ꢀ0.61 (0.20)
19.08 (0.18)
ꢀ27.09 (0.16)
26.02 (0.15)
ꢀ15.15 (0.19)
ꢀ1.14 (0.22)
19.15 (0.20)
ꢀ25.98 (0.16)
24.97 (0.15)
28.72 (0.20)
N6a–B1a–O2a–C3a
C5a–C3a–O2a–B1a
O2a–C3a–C5a–N6a
C3a–C5a–N6a–B1a
O2a–B1a–N6a–C5a
N6a–B1a–O10a–C8a
C7a–C8a–O10a–B1a
N6a–C7a–C8a–O10a
C8a–C7a–N6a–B1a
O10a–B1a–N6a–C7a
C11a–B1a–N6a–C17a
ꢀ12.17 (0.20)
ꢀ2.00 (0.23)
17.43 (0.21)
ꢀ23.20 (0.18)
21.42 (0.21)
ꢀ16.11 (0.19)
8.16 (0.22)
ꢀ20.56 (0.21)
24.28 (0.20)
ꢀ17.32 (0.24)
5.86 (0.28)
10.18 (0.26)
ꢀ18.91 (0.21)
21.50 (0.20)
25.76 (0.26)
ꢀ98.92 (0.27)
ꢀ15.32 (0.23)
19.87 (0.22)
ꢀ10.87 (0.25)
ꢀ6.30 (0.29)
22.48 (0.26)
ꢀ26.91 (0.23)
22.81 (0.21)
21.96 (0.28)
ꢀ79.95 (0.30)
4.95 (0.21)
ꢀ13.63 (0.17)
17.45 (0.16)
21.45(0.21)

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T.M. Percino et al. / Polyhedron 28 (2009) 2771–2775
C17H17BNO4 [M+ + 1]+ Calc. 310.1245, found 310.1249, error
1.2415.
Table 3
Bond distances selected (Å) and torsion angles (°) for C18 H16BN05 (5).
Bond distances (Å)
O2–B1
O3–B1
N1–B1
O2–C1
O3–C4
O1–C1
O4–C4
1.461 (2)
1.485 (2)
1.679 (2)
1.331 (2)
1.313 (2)
1.200 (2)
1.207 (2)
C1–C2
C3–C4
N1–C2
N1–C3
B1–C13
N1–C5
O5–C6
1.509 (3)
1.509 (2)
1.500 (2)
1.492 (2)
1.582 (2)
1.492 (2)
1.218 (2)
4.2.2. Synthesis of (N ? B) phenyl[N-(3-methyl)benzyliminodiacetate-
O,O’,N]borane (3)
Prepared from 1.0 g (4.56 mmol) of compound 1, 0.84
(4.56 mmol) of 3-methylbenzyl bromide b and 1.39 g (13.7 mmol)
of KHCO3 in 120 ml of acetonitrile. The residue was crystallized
from a mixture of dichloromethane/ether, 0.59 g (40%) of com-
pound 4 were obtained as white solid, mp 251 °C 1H NMR
d(DMSO-d6, J = Hz), CH2CO 4.05 (HA, d, J = 16.57), 3.45 (HB, d,
J = 16.57), CH2N 3.55 (s), CH3 2.34 (s), H aromatics 7.0–7.24 (m),
7.40–7.62 (m). 13C NMR: C1 167.9, C2 57.8, R group C3 61.9, C4
141.1, C5 130.5, C6 132.6, C7 125.7, C8 128.5, C9 129.9, C10 21.6,
B-Phenyl Co 135.7, Cm128.1, Cp130.9. 11B NMR: +11.38. HRMS:
C18H19BNO4 [M+ + 1]+ Calc. 324.1401, found 324.1400, error
ꢀ0.5091.
Torsion angles (°)
B1–O2–C1–C2
O2–C1–C2–N1
B1–N1–C2–C1
C2–N1–B1–O2
C1–O2–B1–N1
B1–O3–C4–C3
N1–C3–C4–O3
ꢀ3.09 (0.21)
ꢀ14.41 (0.20)
22.61 (0.16)
ꢀ23.81 (0.15)
17.04 (0.18)
ꢀ5.63 (0.21)
ꢀ14.22 (0.19)
B1–N1–C3–C4
C3–N1–B1–O3
C4–O3–B1–N1
C5–N1–B1–C13
C14–C13–B1–O2
C18–C13–B1–O3
C5–C6–C7–C8
24.94 (0.16)
ꢀ26.94 (0.15)
20.27 (0.18)
ꢀ29.22 (0.20)
ꢀ15.04 (0.25)
34.17 (0.25)
8.57 (0.24)
4.2.3. Synthesis of (N ? B) phenyl[N-(4-methyl)benzyliminodiacetate-
O,O’,N]borane (4)
3. Conclusion
Prepared from 1.0 g (4.56 mmol) of compound 1, 0.62
(4.56 mmol) of 4-methylbenzylbromide c and 1.39 g (13.7 mmol)
of KHCO3 in 120 ml of acetonitrile. The residue was crystallized
from a mixture of dichloromethane/ether, 1.10 g (75%) of com-
pound 5 were obtained as white crystals, mp 187–189 °C. 1H
NMR d(DMSO-d6, J = Hz), CH2CO 4.05 (HA, d, J = 16.5), 3.47 (HB, d,
J = 16.5), CH2N 3.65 (s), CH3 2.36 (s), H aromatics 7.42–7.61 (m),
7.21(H5,9, d, J = 7.9), 7.09 (H6,8 d, J = 7.9), 13C NMR: C1 167.5, C2
58.1, R group C3 60.9, C4 139.9, C5,9 129.1, C6,8 127.4, C7 128.8,
C10 20.9, B-Phenyl Co 132.9, Cm 127.6, Cp128.7. 11B NMR: +11.78.
HRMS: C18H19BNO4 [M+ + 1]+ Calc. 324.1401, found 324.1400, error
ꢀ0.5091.
The new method for the synthesis of six (N ? B) phenyl[N-
alkyliminodiacetate-O,O0,N]boranes improved the yields, evade to
use bases and avoid the use of anhydrous reaction conditions.
Therefore, the identification of all compounds by NMR, their high
resolution mass spectra (HRMS) data are reported, as well as the
crystal structure of compounds 2, 4 and 5 gives evidence of the
N-alkylation of 1 and establish the bicyclic structures due to
N ? B coordination bond.
4. Experimental
4.1. General procedure and measurements
The reagents were purchased from Aldrich Co. (N ? B) phenyl
[iminodiacetate-O,O0,N]borane (1) was prepared as described pre-
viously [14]. 1H, 13C and 11B NMR spectra were recorded on a Jeol
GLX-270, Jeol Eclipse-400 and Bruker Avance and 300-DPX spec-
trometers, DMSO-d6 was used as solvent. The high resolution mass
spectra (HRMS) were taken on Agilent Technologies, model LC/
MSD-TOF spectrometer, coupled to HPLC 1100 with ESI as ioniza-
tion source. Melting points were taken in open capillary tubes on
a Gallenkamp MFB-595 apparatus and are uncorrected.
4.2.4. Synthesis of N ? B) phenyl [N-phenacyliminodiacetate-
O,O’,N]borane (5)
Among of 1.0 g (4.56 mmol) of compound 1, 0.9 g (4.56 mmol)
of phenacyl bromide d and 1.39 g (13.7 mmol) of KHCO3 in
100 ml of a mixture of acetonitrile/benzene (80/20). The residue
was dissolved from a mixture of dichloromethane/acetonitrile
and precipitate with ether to produce 1.04 g (67.5%) of compound
6 were obtained as white crystals. mp 254–255 °C. 1H NMR
d(DMSO-d6, J = Hz): CH2CO 4.60 (HA, d, J = 17.38), 4.34 (HB, d,
J = 17.38), CH2N 4.53 (s), H aromatics 7.40–7.60 (m), 7.54 (H7,9, t,
J = 7.0), 7.63 (H8, t, J = 7.0). 13C NMR: C1 170.37, C2 61.31, R group
C3 65.51, C4 193.10, C5 134.81, C6,10 129.38, C7,9 127.98, C8
134.65. B-Phenyl Co 133.13, Cm128.29, Cp129.66. 11B NMR:
+11.61. HRMS: C18H17BNO5 [M+ + 1]+ Calc. 338.1194, found
338.1188, error ꢀ1.8620.
4.2. Preparation of compounds 2–7
The procedure outlined below is general for the preparation of
compounds 2–7.
4.2.1. Synthesis of (N ? B) phenyl [N-benzyliminodiacetate-
O,O0,N]borane (2)
4.2.5. Synthesis of N ? B) phenyl[N-(4-chloro)
phenacyliminodiacetate-O,O’,N]borane (6)
A suspension of 0.80 g (3.65 mmol) of (N ? B) phenyl[iminodi-
acetate-O,O0,N]borane 1, 0.62 g (3.6 mmol) of benzyl bromide a,
0.62 g (3.65 mmol) and 1.11 g (10.95 mmol) of KHCO3 in 100 ml
of a mixture of acetonitrile/benzene (80/20) was placed into a
250 ml flask equipped with a magnetic stirrer and a Dean–Stark
trap. The suspension was refluxed for 8 h. After being cooled to
room temperature, the solution was filtered and Na2SO4 anhydrous
was added to the solution, which was filtered and the solvent was
evaporated under vacuum. The solid obtained was crystallized
from dichloromethane/hexane to yield 0.68 g (61%) of compound
2 as a white crystals, mp 227 °C. 1H NMR d(DMSO-d6, J = Hz):
CH2CO 4.40 (HA, d, J = 16.5), 3.90 (HB, d, J = 16.5), CH2N 3.80 (s),
H aromatics 7.40–7.60 (m). 13C NMR: C1169.10, C2 57.90, R group
C3 60.80, C4 132.80, C5,9 128.90, C6,8 129.50, C7 127.60, B-Phenyl
Co 131.60, Cm128.80, Cp130.60. 11B NMR: +12.50. HRMS:
Among of 1.0 g (4.56 mmol) of compound 1, 1.06 g (4.56 mmol)
of 2-bromo-40-chloroacetophenone e and 1.39 g (13.7 mmol) of
KHCO3 in 100 ml of a mixture of acetonitrile/benzene (80/20).
The residue was dissolved from a mixture of dichloromethane/ace-
tonitrile and precipitate with ether to produce 1.19 g (73.5%) of
compound 7 were obtained as white crystals, mp 226–227 °C. 1H
NMR d(DMSO-d6, J = Hz): CH2CO 4.59 (HA, d, J = 17.4), 4.33 (HB, d,
J = 17.4), CH2N 4.51 (s), H aromatics 7.39–7.46 (m), 7.56 (H6,10, d,
J = 8.7), 7.54 (H7,9, d, J = 8.7). 13C NMR: C1 170.59, C2 61.57, R group
C3 65.60, C4 192.60, C5 139.79, C6,10 130.17, C7,9 129.86, C8 133.88,
B-Phenyl Co133.88, Cm128.61, Cp129.98. 11B NMR: +12.38. HRMS:
C18H16BNO5Cl [M+ + 1]+ Calc. 372.0804, found 372.0808, error
0.9210.

T.M. Percino et al. / Polyhedron 28 (2009) 2771–2775
2775
4.2.6. Synthesis of N ? B) phenyl[N-(4-phenyl)phenacylimino
diacetate-O,O’,N]borane (7)
residual electron density peak/hole in the final difference map:
0.188/ꢀ0.168 eÅꢀ3
.
Among of 1.0 g (4.56 mmol) of compound 1, 1.25 g (4.56 mmol)
of 2-bromo-4’-phenylacetophenone f and 1.39 g (13.7 mmol) of
KHCO3 in 100 ml of a mixture of acetonitrile/benzene (80/20).
The residue was dissolved from a mixture of dichloromethane/ace-
tonitrile and precipitate with ether to produce 1.52 g (80.8%) of
compound 7 were obtained as yellow crystals, mp 248–249 °C.
1H NMR d(DMSO-d6, J = Hz): CH2CO 4.62 (HA, d, J = 17.5), 4.36
(HB, d, J = 17.5), CH2N 4.56 (s), H aromatics 7.41–7.49 (m), 7.62
(H6, d, J = 7.2), 7.81 (H7 d, J = 7.2), 7.72 (H10, d), 7.49 (H11,12
7.49 m) 13C NMR: C1170.68, C2 61.67, R group C3 65.84, C4
192.94, C5 146.15, C6 127.76, C7 128.03, C8 139.29, C9 129.51, C10
127.85, C11 129.98, C12 133.91. B-Phenyl Co133.46, Cm128.61,
Cp129.51. 11B NMR: +12.92. HRMS: C24H21BNO5 [M+ + 1]+ Calc.
414.1507, found 414.1509, error 0.4110.
Data reduction and molecular graphics were performed by WIN
-
-
GX program set [23]. All calculations were carried out with SHELX
97 and SHELX
-S
-L
-97 [24]. Atomic scattering factors were taken from
the International Tables for X-ray crystallography [25].
Supplementary data
CCDC 714540, 714541 and 714542 contains the supplementary
crystallographic data for compounds 2, 4 and 5, respectively. These
data can be obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44)
1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
Acknowledgments
4.3. Crystal structure determination of compounds 2, 4 and 5
The authors thank the ‘‘Consejo Nacional de Ciencia y Tec-
nología” (Conacyt-México) for financial support and for scholar-
ship to R.M. Flores Ancona and M. López Martínez. We also
acknowledge the help to Ing. Marco Antonio Leyva for X-ray
crystallography.
Diffraction data from compound 2 were collected on an Enraf-
Nonius CCD diffractometer at 293 K. Compound 2 with two inde-
pendent molecules, C17H16BN O4 (MW 309.12) crystallized in the
space group P 21/n, monoclinic; from dichloromethane/hexane as
white colourless block, size 0.3 ꢁ 0.2 ꢁ 0.1 mm3 with a = 10.934
(2), b = 16.927 (4), c = 17.100 (3) Å, V = 3111.0 Å (1)3,
a =
References
90.00o, b = 100.58 (10)o,
= 0.093 mmꢀ1, F(0 0 0) = 1296. Data collection: a total of 12763
reflections were measured, 6988 were independent and of these
4544 were considered observed [Fo > 4.0 (Fo)]. Solution and refine-
ment: direct methods, all non hydrogen atoms were refined aniso-
tropically, R = 0.0499, Rw = 0.1174, w = 1/
2, GOF = 1.017, largest
c q
= 90.00o, = 1.320 mg/m3, Z = 8,
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l
r
r
residual electron density peak/hole in the final difference map:
0.185/ꢀ0.281 eÅꢀ3
.
Compound 4 with two independent molecules, C18H18BNO4
(MW 323.14) crystallized in the space group P 21/c, monoclinic;
from dichloromethane/ether as white colourless block, size
0.3 ꢁ 0.2 ꢁ 0.1 mm3 with a = 11.2761 (4), b = 20.2614 (11),
c = 15.2577 (6) Å, V = 3485.9 (3) Å3,
a
Z = 8,
= 90.00°, b = 89.953 (1)°,
c
= 90.00°,
q
= 1.231 mg/m3,
l
= 0.086 mmꢀ1
,
F(0 0 0) = 1360. Data collection: a total of 19902 reflections were
measured, 7054 were independent and of these 3803 were consid-
ered observed [Fo > 4.0
methods, all non hydrogen atoms were refined anisotropically,
R = 0.0602, Rw = 0.1432, w = 1/
2, GOF = 1.040, largest residual
r(Fo)]. Solution and refinement: direct
r
electron density peak/hole in the final difference map: 0.296/
ꢀ0.342 eÅꢀ3
.
Compound 5, C18H16BNO5 (MW 337.13) crystallized in the
space group P 21/c, monoclinic; from dichloromethane/ether as
white colourless block size 0.3 ꢁ 0.3 ꢁ 0.2 mm3 with a = 7.14030
(10), b = 18.7329 (5), c = 12.3949 (3) Å, V = 1645.10 (6) Å3,
a
l
= 90.00°, b = 97.130 (1)°,
c = 90.00°, q
= 1.361 mg/m3, Z = 4,
= 0.099 mmꢀ1, F(0 0 0) = 704. Data collection: a total of 6705
reflections were measured, 3719 were independent and of these
2324 were considered observed [Fo > 4.0 (Fo)]. Solution and refine-
ment: direct methods, all non hydrogen atoms were refined aniso-
tropically, R = 0.0430, Rw = 0.1497, w = 1/
2, GOF = 0.716, largest
r
r