Synthesis and characterization of oxadisilole-fused acridines, dioxatrisilole-fused acridines and benzo[b]acridines

Article abstract of DOI:10.1016/j.tet.2014.06.031

Oxadisilole-fused acridines, dioxatrisilole-fused acridines and benzo[b]acridines were synthesized through nucleophilic additions and aromatization reactions of arynes with 2-aminoaryl ketones or 2-aminoaryl aldehydes in good yields at room temperature. T

Full text of DOI:10.1016/j.tet.2014.06.031

Tetrahedron 70 (2014) 5820e5827
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis and characterization of oxadisilole-fused acridines,
dioxatrisilole-fused acridines and benzo[b]acridines
*
Jie Zhang, Yali Chen , Xuanming Chen, Xiaoxing Zheng, Weiguo Cao, Jie Chen,
Min Zhang
Department of Chemistry, Innovative Drug Research Center, Shanghai University, Shanghai 200444, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Oxadisilole-fused acridines, dioxatrisilole-fused acridines and benzo[b]acridines were synthesized
through nucleophilic additions and aromatization reactions of arynes with 2-aminoaryl ketones or 2-
aminoaryl aldehydes in good yields at room temperature. The photophysical, redox and thermal prop-
erties of these compounds were characterized. These compounds show potential applications as strong
deep-blue or green emitters for OLED because of high fluorescence quantum yields and good thermal
stabilities.
Received 16 April 2014
Received in revised form 1 June 2014
Accepted 10 June 2014
Available online 5 July 2014
Keywords:
Aryne
Ó 2014 Elsevier Ltd. All rights reserved.
2-Aminoaryl ketones
Oxadisilole-fused acridines
Dioxatrisilole-fused acridines
Benzo[b]acridines
1. Introduction
In the early years, the methods for synthesize acridines required
rather harsh conditions (high temperatures,15 strongly acidic me-
Acridines are one of the important classes of nitrogen containing
heterocyclic compounds. Their synthesis and application have been
dia,16 valued catalyst,17 uncommon reagents or methods18). In re-
cent years, several of reports proved that acridines have been
synthesized from benzyne and 2-aminobenzophenones. In 2005,
Kim et al.19 used 5-arylthianthrenium perchlorates as benzyne
precursors reacted with 2-aminobenzophenone to acquire acri-
dines. This methodology appears to be a really progress in the scope
and yields, except the using of no commercial source for Kim’s
benzyne precursor and highly explosive salt. In 1960s,20 2-
aminobenzophenones have been reported having good reaction
with dimethyl acetylenedicarboxylate to form stable aromatic
compounds. Thus, Larock et al.21 tried their aryne with 2-
aminobenzophenones to find a milder and more efficient way to
synthesize acridines. Recently, we reported the synthesis of het-
erocyclic compounds from our arynes generated from benzobi-
soxadisilole and 2,3-naphthoxadisilole.22 In this paper, we report
our findings on the synthesis of oxadisilole-fused acridines 5aei,
dioxatrisilole-fused acridines 6aei and benzo[b]acridines 10aeg
via nucleophilic additions and aromatization reactions of arynes 3
or 9 with 2-aminoaryl ketones or 2-aminoaryl aldehydes 4aei in
good yields at room temperature. The benzyne 3 or naphthyne 9
€
widely studied since had been first extracted by Carl Grabe and
Heinrich Caro in 1871.1 Due to acridines’ planar tricyclic aromatic
molecules, which possess the ability to intercalate tightly but re-
versibly to DNA helical structure,2 these compounds are one of the
most successful classes of bioactive agents and widely utilized as
antimalarial,3 antiprotozoal,4 antibacterial5 and antileishmanial.6
In addition, acridines, including 9-phenyl acridines, exhibit anti-
cancer activities by inducing apoptosis in human cancer cell
lines.2a,7 Meanwhile, acridine derivatives are of pharmaceutical
interest as an antiseptic in ophthalmic surgery.8 Such an important
class of nitrogen heterocycles also have several significant proper-
ties such as pigment and dye properties,9 photochemical/physical
properties10 and electrochemical properties.11 They have been used
in the construction of new fluorescent probes that emit light at
longer wavelengths in order to inhibit unwanted absorption,
autofluorescence and scattering by neighbouring biological tis-
sue.12 They are also used as an active medium for dye lasers.13
Iridium complexes with acridines have also been used as triplet
state, light emitting materials for applications in OLEDs.14
was generated from benzobis(oxadisilole)
1
or 2,3-
naphthoxadisilole 7, respectively (Schemes 1 and 2).23 The photo-
physical, redox and thermal properties of these previously un-
known 5aei, 6aei or 10aeg were characterized. The possible
mechanism for the formation of products was also suggested.
* Corresponding author. Tel./fax: þ86 21 66132797; e-mail address: ylchen@staff.
shu.edu.cn (Y. Chen).
http://dx.doi.org/10.1016/j.tet.2014.06.031
0040-4020/Ó 2014 Elsevier Ltd. All rights reserved.

J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
5821
Table 1
Si
Si
Si
Si(OH)Me2
I(Ph)OTf
Si
Si
Si
Si
PhI(OAc)2, TfOH
CH2Cl2, 0oC to rt
CsF
Reaction of 2-amino benzophenone 4b (0.4 equiv) with benzyne 3 generated from
benzobis(oxadisilole) 1 (1.0 equiv) using different fluoride sources, solvent and
temperature
O
O
O
O
Si
3
1
2
O
Si
Si
Si
Si
Si(OH)Me2
I(Ph)OTf
Si
Si
Si
Si
PhI(OAc)2, TfOH
CH2Cl2, 0oC to rt
Condition
R2
O
O
O
R1
O
R1
R1
N
R2
R2
Si
O
Si
Si
Si
O
O
NH2
Si
+
3
4a-i
1
2
N
O
a: R1 = C6H5,
b: R1 = C6H5,
c: R1 = C6H5,
d: R1 = C6H5,
R2 = CH3
R2 = H
5a-i
6a-i
R2 = Cl
NH2
4b
R2 = NO2
Si
Si
O
Si
O
Si
e: R1 = 4-FC6H4, R2 = H
f: R1 = 2-FC6H4, R2 = Cl
Si
+
g: R1 = H,
h: R1 = H,
i: R1 = CH3,
R2 = H
R2 = Cl
R2 = H
O
N
N
6b
5b
Scheme 1. Syntheses of oxadisilole-fused acridines 5aei and dioxatrisilole-fused ac-
ridines 6aei.
Entry
Conditions
Yielda of 5bD6b %
1
2
3
4
5
6
7
8
CsF (1.0 equiv), CH3CN, 0 ꢀC
CsF (1.0 equiv), CH3CN, r.t
CsF (1.0 equiv), CH3CN, 40 ꢀC
CsF (1.0 equiv), CH3CN, 60 ꢀC
CsF (1.0 equiv), CH3CN, reflux
CsF (2.0 equiv), CH3CN, rt.
CsF (3.0 equiv), CH3CN, rt.
KF (1.0 equiv), CH3CN, rt.
TBAF (1.0 equiv), CH3CN, rt.
CsF (1.0 equiv), Toluene, rt.
CsF (1.0 equiv), THF, rt.
70
84
58
67
48
58
76
71
41
35
72
77
Si
Si
Si(OH)Me2
I(Ph)OTf
PhI(OAc)2, TfOH
CH2Cl2, 0oC to rt
CsF
O
9
7
8
O
R2
R1
a: R1 = C6H5,
b: R1 = C6H5,
c: R1 = C6H5,
d: R1 = C6H5,
R2 = CH3
9
R1
R2 = H
10
11
12
NH2
R2 = Cl
R2 = NO2
R2
4a-g
e: R1 = 4-FC6H4, R2 = H
f: R1 = 2-FC6H4, R2 = Cl
CsF (1.0 equiv), DCM, rt.
N
10a-g
g: R1 = H,
R2 = H
a
Isolated yield.
Scheme 2. Syntheses of benzo[b]acridines 10aeg.
carried out in various solvents, such as toluene, THF or DCM at room
temperature, the results are tabulated in Table 1 (Entries 10e12).
The optimal conditions were obtained when the reaction of
oxadisilole-fused benzyne 3 and 4b (0.4 equiv) was carried out in
CH3CN at room temperature, and CsF (1.0 equiv) as fluoride source
(Table 1, entry 2).
2. Results and discussion
The syntheses of
oxadisilole-fused
acridines
5aei,
dioxatrisilole-fused acridines 6aei or benzo[b]acridines 10aeg are
outlined in Schemes 1 and 2. Arynes 3 and 9 were generated from
benzobis(oxadisilole) 1 and 2,3-naphthoxadisilole 7, respectively,
through our previously reported phenyliodination fluoride induced
desilylation protocol.23 Trapping benzyne 3 and naphthyne 9 at
room temperature with 2-aminoaryl ketones or 2-aminoaryl al-
dehydes 4aei by nucleophilic additions and aromatization re-
actions afforded oxadisilole-fused acridine derivatives 5aei,
dioxatrisilole-fused acridine derivatives 6aei and benzo[b]acri-
dine derivatives 10aeg in good yields.
We optimized the procedure by starting with the reaction of 2-
amino benzophenone 4b and oxadisilole-fused benzyne 3 gener-
ated in situ from benzobis(oxadisilole) 1. Phenyliodination of 1
(1.0 equiv) took place readily at room temperature in dichloro-
methane with a 1:2 mixture of phenyliodium diacetate (PhI(OAc)2)
and trifluoromethanesulfonic acid (TfOH) (Table 1). Without iso-
lation of the ring-opened iodination intermediate 2, the solvent
(CH2Cl2) was removed under reduced pressure, benzyne 3 could be
generated in situ upon treatment with a cesium fluoride (CsF)
(1.0 equiv) in acetonitrile (CH3CN). Trapping experiments were
carried out with 2-amino benzophenone 4b (0.4 equiv) at 0 ꢀC to
form oxadisilole-fused acridine derivative 5b and dioxatrisilole-
fused acridine derivative 6b in overall 70% yield (Table 1, entry 1).
When the reaction temperature was changed from 0 ꢀC to room
temperature, 40 ꢀC, 60 ꢀC, or reflux, the yield of desired products
(5b and 6b) was changed from 70% to 84%, 58%, 67% or 48%, re-
spectively (Table 1, entries 2e5). At room temperature, using
2.0 equiv or 3.0 equiv of CsF as fluoride source, the isolated yield of
products (5b and 6b) were 58% or 76%, respectively (Table 1, entries
6 and 7). Using 1.0 equiv of potassium fluoride (KF) or tetrabuty-
lammonium fluoride (TBAF) in CH3CN at room temperature, the
isolated yield of mixture products (5b and 6b) were 71% or 41%,
respectively (Table 1, entries 8 and 9). When the reaction was
We further studied the nucleophilic additions and aromatiza-
tion reactions of benzyne 3 generated in situ from benzobis(ox-
adisilole) 1 with 2-aminoaryl ketones or 2-aminoaryl aldehydes
4aei at room temperature. The oxadisilole-fused acridines 5aei
and dioxatrisilole-fused acridines 6aei were formed in 30%e89%
total yields (Scheme 1 and Table 2, entries 1e9).
As shown in Table 2, the reaction of 2-amino benzophenone 4b
(R1¼C6H5, R2¼H) or 2-amino acetophenone (R1¼CH3, R2¼H) 4i
with 3 gave higher total yields (Table 2, entry 2 or 9). The reaction of
2-amino benzophenone 4d (R1¼C6H5, R2¼NO2) or 2-amino benz-
aldehyde (R1¼H, R2¼H) 4g with 3 gave lower total yields (Table 2,
entry 4 or 7). The ratio of 5 and 6 was determined by 1H NMR on the
mixture of 5 and 6. The oxadisilole-fused acridines 5aei was the
major product.
Table 2
Syntheses of 5aei and 6aei from 4aei with benzyne 3 generated from benzobi-
s(oxadisilole) 1 via Scheme 1
Entry
Reactant
R1
R2
Products 5
and 6
Yielda,b of 5D6
(5:6) %
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4e
4f
4g
4h
4i
C6H5
C6H5
C6H5
C6H5
4-FC6H4
2-FC6H4
H
CH3
H
Cl
NO2
H
Cl
H
Cl
H
5a, 6a
5b, 6b
5c, 6c
5d, 6d
5e, 6e
5f, 6f
5g, 6g
5h, 6h
5i, 6i
57 (34:23)
84 (44:40)
45 (28:17)
35 (22:13)
62 (44:18)
55 (34:21)
30 (17:13)
56 (43:13)
89 (60:29)
H
CH3
a
Isolated yield.
b
The ratio of 5 and 6 was determined by 1H NMR on the mixture of 5 and 6.
During this study, we found that the mixture of oxadisilole-
fused acridines 5aei and dioxatrisilole-fused acridines 6aei were
synthesized via the two-step nucleophilic addition and

5822
J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
aromatization reaction of benzyne 3 with 2-aminoaryl ketones or
2-aminoaryl aldehydes 4aei at room temperature. One possible
mechanistic pathway is shown in Scheme 3. When benzyne 3 is
generated from benzobis(oxadisilole) 1 by a phenyliodination/
fluoride induced desilylation protocol, dimethylsilanone 11 is pos-
sibly generated by decomposition involving the conversion of an
initial reactive silicon-containing intermediate into a silanone.
Subsequent insertion of dimethylsilanone 11 into the SieO single
bond of oxadisilole-fused benzyne 3 leads to dioxatrisilole-fused
benzyne 14,24 the dioxatrisilole-fused acridines 6aei were
formed via the nucleophilic addition and aromatization reaction of
benzyne 14 with 2-aminoaryl ketones or 2-aminoaryl aldehydes
4aei at room temperature.
The structures of compounds 5aei, 6aei and 10aeg were
established by 1H and 13C NMR spectroscopies, IR spectroscopy, MS
and high-resolution (HR) MS, which are in good agreement with
the expected structures.
The absorption spectra of 5aef, 6aef and 10aef were measured
in CH2Cl2 and the spectra data are summarized in Table 4. The
absorption spectra of 5aef, 6aef and 10aef show the characteristic
strong
b-band absorption at approximately 268 nm for 5aef,
270 nm for 6aef and 285 nm for 10aef, with the long wavelength
absorption bands located between 368 and 380 nm for 5aef, 368
and 376 nm for 6aef, and 399 and 402 nm for 10aef (Figs. 1e3). A
slight red shift is observed for the absorption maximum of 10aef
compared with 5aef or 6aef due to extended conjugation in the
latter compounds 10aef. A substituent effect is also observed in the
5aef and 6aef series, with electron-donating groups (R2¼CH3) in
5a or 6a and electron-withdrawing groups (R2¼Cl or NO2) in 5c,d,f
or 6c,d,f producing a slight red shift in the absorption with respect
to electronically neutral groups (R2¼H) in 5b,e or 6b,e. In addition,
10aef series show similar wavelength in the absorption.
O
C
R2
R1
H2N
R1
C
O
Si
Si
R2
Si
Si
4a-i
O
O
Si
Si
Si(OH)Me2
I(Ph)OTf
N
CaF
H2
3
O
12a-i
Table 4
+
Summary of optical measurements and thermal properties of 5aef, 6aef and 10aef
Si
O
2
R1
HO
a,c
a,d
e
Compound
labs a,b [nm]
lem
FFL
Tm [ꢀC]
Tdec
C
11
Si
R2
max
max
(εmax 104/Mꢁ1 cmꢁ1
)
[nm]
[ꢀC]
O
Si
N
Si
Si
Si
Si
O
Si
O
Si
O
5a
5b
5c
5d
5e
5f
6a
6b
6c
6d
6e
6f
10a
10b
10c
10d
10e
10f
370(3.48)
368(1.08)
376(0.78)
376(0.51)
368(1.56)
380(0.72)
371(1.11)
368(2.02)
373(1.35)
376(0.79)
368(1.25)
376(1.40)
400(0.78)
399(1.13)
402(1.69)
400(0.27)
400(1.29)
402(2.88)
504
502
505
521
503
498
502
501
504
520
500
501
521
525
527
602
524
526
0.27
0.47
0.34
0.30
0.39
0.56
0.16
0.42
0.29
0.44
0.30
0.46
0.47
0.40
0.38
0.56
0.48
0.46
127
100
169
201
148
153
169
174
180
172
153
170
145
221
189
262
191
243
320
292
329
346
240
324
317
326
353
326
309
341
270
322
335
292
384
324
13a-g
O
H
Aromatization
Si
1
14
4a-i
R1
Si
Si
R2
O
R1
N
5a-i
O
C
Si
R2
O
Si
O
Si
N
H2
15a-i
R1
HO
R1
C
Si
Si
R2
Aromatization
Si
Si
R2
O
Si
O
O
Si
O
N
N
H
6a-i
16a-i
Scheme 3. Possible mechanism for the formation of oxadisilole-fused acridines 5aei
and dioxatrisilole-fused acridines 6aei.
a
Measured in CH2Cl2.
Excited at the absorption maximum.
Excited at the emission maximum.
b
c
Our attention was then turned to the nucleophilic additions and
aromatization reactions of naphthyne 9 generated in situ from the
2,3-naphthoxadisilole 7 with 2-aminoaryl ketones or 2-aminoaryl
aldehydes 4aeg. To our delight, 2-aminoaryl ketones or 2-
aminoaryl aldehydes 4aeg successfully participated in the nucle-
ophilic additions and aromatization reactions with naphthyne 9 at
room temperature to afford the corresponding benzo[b]acridine
derivatives 10aeg in 47e75% total yields (Scheme 2 and Table 3,
entries 1e7). As shown from the yields, the reaction of 2-amino
benzaldehyde 4g with naphthyne 9 gave lower yields of 10g
(Scheme 2, Table 3, entry 7). We have tried the reaction of naph-
thyne 9 with 4i (R1¼CH3, R2¼H), but no product was obtained in
this process.
d
Using quinine in 0.1 N H2SO4
(
F365¼0.54) as a standard for the oxadisilole-fused
acridines 5aef, dioxatrisilole-fused acridines 6aef or the benzo[b]acridines 10aef.
e
Determined by thermal gravimetric analyzer with a heating rate of 10 ꢀC minꢁ1
under N2.
5a
5b
5c
5d
5e
5f
2.5x105
2.0x105
3x104
1.5x105
2x104
Table 3
Syntheses of 10aeg from 4aeg with naphthyne
naphthoxadisilole 7 via Scheme 2
9
generated from 2,3-
1.0x105
1x104
Entry
Reactant
R1
R2
Product
Yeilda of 10aeg %
5.0x104
1
2
3
4
5
6
7
4a
4b
4c
4d
4e
4f
C6H5
C6H5
C6H5
C6H5
4-FC6H4
2-FC6H4
H
CH3
H
Cl
NO2
H
Cl
10a
10b
10c
10d
10e
10f
47
68
59
53
75
62
42
360
370
380
390
0.0
250
300
350
400
Wavelength / nm
Fig. 1. Absorption spectra of 5aef in CH2Cl2.
4g
H
10g
a
Isolated yield.

J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
5823
1.6x105
1.4x105
1.2x105
1.0x105
8.0x104
6.0x104
4.0x104
6a
6b
6c
5a
5b
5c
5d
5e
5f
1.0
6d
6e
6f
2.0x104
1.5x104
1.0x104
5.0x103
0.8
0.6
0.4
360
370
380
390
% (?X)
2.0x104
0.0
0.2
0.0
250
300
350
400
Wavelength / nm
450
500
550
600
650
Fig. 2. Absorption spectra of 6aef in CH2Cl2.
Wavelength / nm
3.5x105
3.0x105
2.5x105
2.0x105
1.5x105
1.0x105
10a
Fig. 4. Emission spectra of 5aef in CH2Cl2.
10b
10c
10d
10e
10f
6a
6b
6c
6d
6e
6f
3x104
2x104
1.0
0.8
0.6
0.4
0.2
0.0
1x104
0
5.0x104
0.0
390
405
420
250
300
350
400
450
Wavelength / nm
Fig. 3. Absorption spectra of 10aef in CH2Cl2.
The photoluminescence spectra of 5aef, 5aef and 10aef in
CH2Cl2 show strong deep-blue or green emitters with maxima in
the range of 498e521 nm for series 5aef, 500e520 nm for series
6aef and 521e602 nm for series 10aef (Figs. 4e6, Table 4). A
substituent effect was also found for the maximum emission in
5aef, 6aef and 10aef, that is, by using the electron-withdrawing
groups substituents in 5d, 6d or 10d (R2¼NO2), gives a red shift
of 19 nm (5d) compared to 5b (R2¼H), 19 nm (6d) compared to 6b
(R2¼H), and 77 nm (10d) compared to 10b (R2¼H). The weaker
electron-donating (R2¼CH3) or electron-withdrawing substituents
(R2¼Cl) in 5a,c,f, 6a,c,f or 10a,c,f compared to electronically neutral
substituents (R2¼H) in 5b, 6b or 10b, show similar emission
wavelength. Compounds with substituent effect in the 5aef, 6aef
and 10aef series in emission spectra, the nitro group showed an
obvious red shift in emission spectra. However, other substituent
groups exhibited similar results in wavelength photoluminescence.
450
500
550
600
650
Wavelength / nm
Fig. 5. Emission spectra of 6aef in CH2Cl2.
10a
10b
10c
10d
10e
10f
1.0
0.8
0.6
0.4
0.2
0.0
The fluorescence quantum yields (F) measured in CH2Cl2 by using
quinine as reference for 5aef, 6aef and 10aef are in the range of
27e56% for 5aef, 16e46% for 6aef and 38e56% for 10aef, re-
spectively. Thus, molecules 5aef, 6aef and 10aef show potential
applications as strong deep-blue or green emitters for organic light-
emitting diode (OLED). In addition, the thermal properties of these
three series compounds were determined by thermal gravimetric
analysis (TGA). In general, they show good thermal stability, rang-
ing from 240 to 384 ꢀC. TGA results were determined by tangent of
the curve to the baseline at the onset of 5% weight loss.
500
600
700
Wavelength/nm
Fig. 6. Emission spectra of 10aef in CH2Cl2.

5824
J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
The redox properties as well as the HOMO (highest occupied
4. Experimental section
4.1. General methods
molecular orbital) and LUMO (lowest unoccupied molecular or-
bital) energy levels of 5aef, 6aef and 10aef are tabulated in Table
5. The redox properties of the 5aef, 6aef and 10aef series were
studied by cyclic voltammetry, which was carried out in a three-
electrode cell setup with 0.1 M of Bu4NPF6 as a supporting elec-
trolyte in CH3CN. All of the potentials reported are referenced to Fc/
Fcþ as standard. In contrast to the optical properties, the oxidation
potential (Eox) lies in the range of 0.97e1.44 V for 5aef, 1.03e1.23 V
for 6aef and 0.97e1.40 V for 10aef. The HOMO energy values were
calculated by the equation of Janietz or Schmidt,25 and the LUMO
energy levels were obtained by subtraction of the optical band gap
from the HOMO. Molecules within the same series, that is, 5aef or
6aef, show similar HOMO energies. In addition, the band gaps
within the same series are also very similar. Tendencies are ap-
parent that the band gap values of compounds 10aef are smaller
than compounds 5aef and 6aef. This is mainly contributed to their
enhanced conjugation, which lower the energy levels between
HOMO and LUMO.
Purification was effected by silica gel column chromatography
(200e300 mesh silica gel) using mixtures of reagent-grade EtOAc/
petroleum ether (PE, 60e80 ꢀC) as eluents. NMR spectra were
recorded with a Bruker DRX-500 NMR spectrometer at 500 MHz for
1H and at 125 MHz for 13C with CDCl3 as solvent. Chemical shifts are
reported in parts per million on the
d scale relative to the residual
resonance of CHCl3
(
d
¼7.26 ppm for 1H and 77.00 ppm for the
central peak of the triplet in 13C). Coupling constants (J) are re-
ported in Hertz. IR spectra were recorded with an FTIR spectrom-
eter in KBr discs. Low-resolution mass spectra were recorded with
an Agilent spectrometer in EI or API-ES mode are reported as m/z
values. High-resolution mass spectra were recorded with a Waters
Micromass GCT instrument. The fluorescence quantum yields in
solution were determined by the dilution method using quinine in
1.0 N H2SO4
(
F365¼0.54) as standard with a LS-55 spectrometer.
Thermal stabilities were determined by thermal gravimetric ana-
lyzer with heating rate of 10 ꢀC minꢁ1 under N2.
Table 5
Summary of oxidation potential, HOMO and LUMO energy levels of 5aef, 6aef and
10aef
4.1.1. General procedure for the preparation of oxadisilole fused ac-
ridines 5aei, dioxatrisilole-fused acridines 6aei or benzo[b]acridine
derivatives 10aeg. TfOH (0.14 mL, 1.50 mmol) was added by means
of a syringe to a stirred solution of PhI(OAc)2, (247 mg, 0.75 mmol)
in CH2Cl2 (10 mL) at 0 ꢀC under N2. The mixture was stirred under
N2 at 0 ꢀC for 1 h and at room temperature for 2 h. The clear
yellow solution was cooled again to 0 ꢀC, followed by dropwise
addition into the cold solution of the benzobis(oxadisilole) 1 (or
2,3-naphthoxadisilole 7) (0.5 mmol) in CH2Cl2 (5 mL) at 0 ꢀC. The
mixture was stirred at 0 ꢀC for 0.5 h and at room temperature for
3 h. The clear yellow solution was washed with water (200 mL)
and was extracted by CH2Cl2 three times. Then the low yellow
solid was obtained under reduced pressure and resolved in CH3CN
(5 mL). The solution of 2-aminoaryl ketones or 2-aminoaryl al-
dehydes 4aei (0.2 mmol) and CsF (76 mg, 0.5 mmol) in CH3CN
(5 mL) was dropwise added into low yellow solution of 2 (or 8),
The mixture stirred under N2 at room temperature until 4aei was
disappeared (monitored by TLC). The crude product was purified
by column chromatography on silica gel using a gradient of 4e5%
EtOAc in PE (60e80 ꢀC) as the eluent to afford products 5aei, 6aei
and 10aeg.
Compound
Eoxa, V
HOMOb, eV
Band gapc, eV
LUMOd, eV
5a
5b
5c
5d
5e
5f
6a
6b
6c
6d
6e
6f
10a
10b
10c
10d
10e
10f
1.44
1.33
1.03
1.02
1.09
0.97
1.22
1.03
1.21
1.06
1.10
1.23
1.21
1.32
1.40
0.97
1.33
1.00
ꢁ6.17
ꢁ6.06
ꢁ5.76
ꢁ5.75
ꢁ5.82
ꢁ5.70
ꢁ5.95
ꢁ5.76
ꢁ5.94
ꢁ5.79
ꢁ5.83
ꢁ5.96
ꢁ5.94
ꢁ6.05
ꢁ6.13
ꢁ5.70
ꢁ6.06
ꢁ5.73
3.50
3.49
3.49
3.54
3.52
3.44
3.49
3.35
3.44
3.54
3.35
3.44
2.95
3.17
2.76
3.49
2.88
2.76
ꢁ2.67
ꢁ2.57
ꢁ2.27
ꢁ2.21
ꢁ2.30
ꢁ2.26
ꢁ2.46
ꢁ2.41
ꢁ2.50
ꢁ2.25
ꢁ2.48
ꢁ2.47
ꢁ2.99
ꢁ2.88
ꢁ3.37
ꢁ2.21
ꢁ3.18
ꢁ2.97
a
Eox was estimated by CV in CH3CN with a platinum disk electrode as the
working electrode, a platinum wire as the counter electrode and SCE as the refer-
ence electrode with an agar salt bridge connecting the compound solution and
ferrocene as an external standard, and 0.1 M Bu4NPF6 at a scan rate of 100 mV/s, E1/
2(Fc/Fcþ)¼0.49 V versus SCE, calculated with ferrocene (4.8 eV vs vacuum).
4.1.1.1. 2,3-Dioxatrisilole-7-methyl-9-phenyl-acridine
b
HOMO¼Eoxꢁ[E1/2(Fc/Fcþ)]þ4.8.
(5a). Yield: 27.2 mg, 34%; yellow powder; mp 126e128 ꢀC; 1H NMR
c
Estimated from the absorption edge in CH2Cl2.
d
LUMO¼HOMOþOptical band gap.
(500 MHz, CDCl3):
d 0.35 (s, 6H, SiMe2), 0.47 (s, 6H, SiMe2), 2.45 (s,
3H, CH3), 7.40 (s, 1H, AreH), 7.43e7.45 (m, 2H, AreH), 7.62e7.66 (m,
4H, AreH), 7.86 (s, 1H, AreH), 8.23 (d, J¼8.5 Hz, 1H, AreH), 8.52 (s,
1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 1.0, 1.2, 22.0, 124.8,
3. Conclusions
125.3, 125.5, 128.3, 128.5, 129.2, 129.9, 130.4, 132.7, 133.2, 135.6,
136.0, 143.2, 146.5, 147.7, 147.8, 148.0 ppm; IR (KBr, cmꢁ1) 3440,
2954, 1631, 1252; MS (EI): m/z (%)¼400 (100, [MþH]þ); HRMS (EI):
[MþH]þ, found: 400.1547. C24H25NOSi2 requires 400.1552.
Three unknown series of oxadisilole-fused acridines 5aei,
dioxatrisilole-fused acridines 6aei and benzo[b]acridines 10aeg
have been synthesized, respectively, by the nuclephilic additions
and aromatization reactions of 2-aminoaryl ketones or 2-aminoaryl
aldehydes 4aei with arynes 3 or 9 generated in situ from benzo-
bis(oxadisilole) 1 or 2,3-naphthoxadisilole 7 in good yields at room
temperature. This simple and efficient synthetic method could offer
great opportunities for the syntheses of important heterocyclic
compounds. The photophysical, redox and thermal properties of
oxadisilole-fused acridines 5aef, dioxatrisilole-fused acridines
6aef and benzo[b]acridines 10aef have been characterized. These
compounds show potential applications as strong deep-blue or
green emitters for OLED, because of their high fluorescence quan-
tum yields and thermal stabilities.
4.1.1.2. 2,3-Oxadisilole-9-phenyl-acridine (5b). Yield: 33.9 mg,
44%; yellow powder; mp 99e101 ꢀC; 1H NMR (500 MHz, CDCl3):
d
0.37 (s, 6H, SiMe2), 0.49 (s, 6H, SiMe2), 7.39e7.44 (m, 1H, AreH),
7.45e7.47 (m, 2H, AreH), 7.60e7.64 (m, 3H, AreH), 7.68 (d,
J¼8.5 Hz, 1H, AreH), 7.74e7.78 (m, 1H, AreH), 7.92 (s, 1H, AreH),
8.28 (d, J¼8.5 Hz, 1H, AreH), 8.53 (s, 1H, AreH) ppm; 13C NMR
(125 MHz, CDCl3):
d 1.0, 1.2, 125.1, 125.5, 125.7, 126.9, 128.3, 128.4,
129.6, 130.0, 130.1, 130.5, 132.9, 135.9, 143.3, 147.5, 148.2, 148.5,
149.1 ppm; IR (KBr, cmꢁ1) 3433, 3316, 1628, 1248; MS (EI): m/z (%)¼
385 (2, [MþH]þ), 196 (100); HRMS (EI): [MþH]þ, found: 385.1318.
C23H23NOSi2 requires 385.1312.

J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
5825
4.1.1.3. 2,3-Oxadisilole-7-chloro-9-phenyl-acridine (5c). Yield:
23.5 mg, 28%; light yellow powder; mp 168e170 ꢀC; 1H NMR
J¼2.5 Hz, 1H, AreH), 8.18 (d, J¼9.0 Hz, 1H, AreH), 8.22 (s, 1H, AreH),
8.43 (s, 1H, AreH), 8.70 (s, 1H, AreH) ppm; 13C NMR (125 MHz,
(500 MHz, CDCl3):
d
0.36 (s, 6H, SiMe2), 0.49 (s, 6H, SiMe2), 7.43 (d,
CDCl3): d 1.0,1.2,126.4,126.9,127.0,131.2,131.57,131.60,131.7,132.6,
J¼2.0 Hz, 1H, AreH), 7.44 (d, J¼2.0 Hz, 1H, AreH), 7.62e7.66 (m, 5H,
135.4, 144.2, 147.7, 148.9, 149.4 ppm; IR (KBr, cmꢁ1) 3448, 2922,
1614, 1250; MS (EI): m/z (%)¼344 (100, [MþH]þ); HRMS (EI):
[MþH]þ, found: 344.0688. C17H18ClNOSi2 requires 344.0695.
AreH), 7.90 (s, 1H, AreH), 8.21 (d, J¼8.5 Hz, 1H, AreH), 8.51 (s, 1H,
AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 0.9,1.1, 125.1, 125.3,125.7,
128.6, 129.9, 130.3, 131.29, 131.33, 131.6, 132.9, 135.2, 144.3, 146.6,
147.3, 148.5, 148.7 ppm; IR (KBr, cmꢁ1) 3442, 2955, 1613, 1251; MS
(EI): m/z (%)¼419 (63, [MþH]þ), 404 (100); HRMS (EI): [MþH]þ,
found: 419.0928. C23H22ClNOSi2 requires 419.0927.
4.1.1.9. 2,3-Oxadisilole-9-methyl-acridine (5i). Yield: 38.8 mg,
60%; yellow solid; mp 182e184 ꢀC; 1H NMR (500 MHz, CDCl3):
d 0.47
(s, 6H, SiMe2), 0.49 (s, 6H, SiMe2), 3.16 (s, 3H, CH3), 7.52e7.56 (m,1H,
AreH), 7.74e7.77 (m, 1H, AreH), 8.23e8.25 (m, 2H, AreH), 8.468 (s,
1H, AreH), 8.473 (s, 1H, AreH), ppm; 13C NMR (125 MHz, CDCl3):
4.1.1.4. 2,3-Oxadisilole-7-nitro-9-phenyl-acridine
18.9 mg, 22%; luminous yellow powder; mp 200e201 ꢀC; 1H NMR
(500 MHz, CDCl3): 0.37 (s, 6H, SiMe2), 0.48 (s, 6H, SiMe2),
(5d). Yield:
d
1.0, 1.3, 13.6, 124.6, 125.5, 125.6, 125.8, 127.7, 130.0, 130.1, 133.2,
d
143.0,143.1,147.8,148.2,148.4 ppm; IR (KBr, cmꢁ1) 3422, 2918,1624,
1252; MS (EI): m/z (%)¼323 (67, [MþH]þ), 100 (100); HRMS (EI):
[MþH]þ, found: 323.1162. C18H21NOSi2 requires 323.1165.
7.46e7.48 (m, 2H, AreH), 7.68e7.69 (m, 3H, AreH), 7.94 (s, 1H,
AreH), 8.34 (d, J¼9.5 Hz, 1H, AreH), 8.46 (dd, J¼9.5, 2.5 Hz, 1H,
AreH), 8.51 (s, 1H, AreH), 8.68 (d, J¼2.5 Hz, 1H, AreH) ppm; 13C
NMR (125 MHz, CDCl3):
d
0.9, 1.1, 122.9, 123.7, 125.0, 125.5, 128.9,
4.1.1.10. 2,3-Dioxatrisilole-7-methyl-9-phenyl-acridine
129.3, 130.2, 130.4, 131.7, 133.0, 134.3, 144.8, 145.4, 149.6, 150.3,
151.3, 151.4 ppm; IR (KBr, cmꢁ1) 3440, 2958, 1624, 1339; MS (EI): m/
z (%)¼430 (55, [MþH]þ), 415 (100); HRMS (EI): [MþH]þ, found:
430.1169. C23H22N2O3Si2 requires 430.1173.
(6a). Yield: 21.8 mg, 23%; yellow powder; mp 168e170 ꢀC; 1H NMR
(500 MHz, CDCl3): d 0.13 (s, 6H, SiMe2), 0.300 (s, 6H, SiMe2), 0.55 (s,
6H, SiMe2), 2.46 (s, 3H, CH3), 7.43 (d, J¼2.0 Hz, 1H, AreH), 7.45 (d,
J¼2.0 Hz, 1H, AreH), 7.49 (s, 1H, AreH), 7.59e7.65 (m, 4H, AreH),
7.90 (s, 1H, AreH), 8.22 (d, J¼9.0 Hz, 1H, AreH), 8.48 (s, 1H, AreH)
4.1.1.5. 2,3-Oxadisilole-9-(4-fluoro phenyl)-acridine (5e). Yield:
35.5 mg, 44%; dark yellow powder; mp 147e149 ꢀC; 1H NMR
(500 MHz, CDCl3):
ppm; 13C NMR (125 MHz, CDCl3):
d 0.7, 1.7, 2.1, 22.0, 124.2, 124.9,
125.6, 128.3, 129.3, 130.4, 133.2, 133.5, 135.6, 135.7, 141.3, 146.1,
146.2, 147.3, 148.2 ppm; IR (KBr, cmꢁ1) 3422, 29,601, 16,321, 1257;
MS (EI): m/z (%)¼474 (14, [MþH]þ), 57 (100); HRMS (EI): [MþH]þ,
found: 474.1735. C26H31NO2Si3 requires 474.1736.
d 0.37 (s, 6H, SiMe2), 0.48 (s, 6H, SiMe2),
7.32e7.35 (m, 2H, AreH), 7.42e7.45 (m, 3H, AreH), 7.65 (d,
J¼8.5 Hz, 1H, AreH), 7.75e7.79 (m, 1H, AreH), 7.87 (s, 1H, AreH),
8.27 (d, J¼8.5 Hz, 1H, AreH), 8.52 (s, 1H, AreH) ppm; 13C NMR
(125 MHz, CDCl3):
d
1.0, 1.2, 115.7 (d, J¼21.3 Hz), 125.2, 125.6, 125.9,
4.1.1.11. 2,3-Dioxatrisilole-9-phenyl-acridine (6b). Yield: 36.7 mg,
40%; pale yellow lump crystal; mp 173e174 ꢀC; 1H NMR (500 MHz,
126.6, 129.7 (d, J¼8.8 Hz), 130.2, 131.7 (d, J¼3.8 Hz), 132.2 (d,
J¼7.5 Hz), 132.9, 136.1, 143.7, 146.3, 148.3, 148.4, 149.1, 161.8,
CDCl3):
d 0.14 (s, 6H, SiMe2), 0.32 (s, 6H, SiMe2), 0.56 (s, 6H, SiMe2),
163.8 ppm; 19F NMR (470 MHz, CDCl3):
d
ꢁ113.1 (s, AreF) ppm; IR
7.42e7.47 (m, 3H, AreH), 7.58e7.63 (m, 3H, AreH), 7.76e7.79 (m,
2H, AreH), 7.95 (s, 1H, AreH), 8.28e8.30 (m, 1H, AreH), 8.49 (s, 1H,
(KBr, cmꢁ1) 3437, 2959, 1626, 1246; MS (EI): m/z (%)¼403 (2,
[MþH]þ), 214 (100); HRMS (EI): [MþH]þ, found: 403.1224.
AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 0.7, 1.7, 2.0, 124.0, 125.6,
C
23H22FNOSi2 requires 403.1229.
125.7, 126.9, 128.3,128.4,129.6, 130.2,130.4,133.6,135.4,136.1, 141.4,
146.8, 147.2, 147.9, 149.3 ppm; IR (KBr, cmꢁ1) 3450, 2961, 1621, 1258;
MS (EI): m/z (%)¼459 (44, [MþH]þ), 444 (100); HRMS (EI): [MþH]þ,
found: 459.1506. C25H29NO2Si3 requires 459.1503.
4.1.1.6. 2,3-Oxadisilole-7-chloro-9-(2-fluoro phenyl)-acridine
(5f). Yield: 29.7 mg, 34%; yellow powder; mp 152e154 ꢀC; 1H
NMR (500 MHz, CDCl3):
d 0.36 (s, 3H, SiMe2), 0.38 (s, 3H, SiMe2),
0.47 (s, 3H, SiMe2), 0.48 (s, 3H, SiMe2), 7.37e7.41 (m, 2H, AreH),
7.42e7.45 (m, 1H, AreH), 7.59 (s, 1H, AreH), 7.62e7.67 (m, 1H,
AreH), 7.70 (dd, J¼9.0, 2.5 Hz, 1H, AreH), 7.82 (s, 1H, AreH), 8.24 (d,
J¼9.0 Hz, 1H, AreH), 8.50 (s, 1H, AreH) ppm; 13C NMR (125 MHz,
4.1.1.12. 2,3-Dioxatrisilole-7-chloro-9-phenyl-acridine
(6c). Yield: 25.1 mg, 17%; pale yellow lump crystal; mp 179e180 ꢀC;
1H NMR (500 MHz, CDCl3):
d 0.14 (s, 6H, SiMe2), 0.31 (s, 6H, SiMe2),
0.56 (s, 6H, SiMe2), 7.44 (d, J¼6.5 Hz, 2H, AreH), 7.60e7.63 (m, 3H,
AreH), 7.68 (dd, J¼9.0, 2.0 Hz, 1H, AreH), 7.73 (d, J¼2.0 Hz, 1H,
AreH), 7.92 (s, 1H, AreH), 8.22 (d, J¼9.0 Hz, 1H, AreH), 8.46 (s, 1H,
CDCl3):
d
0.9, 1.0, 1.1, 1.2, 116.3 (d, J¼21.3 Hz), 122.6 (d, J¼17.5 Hz),
124.5 (d, J¼3.8 Hz), 124.6, 125.4, 125.9, 129.3, 131.2 (d, J¼7.5 Hz),
131.5 (d, J¼5.0 Hz), 132.1, 132.4 (d, J¼2.5 Hz), 133.0, 140.4, 144.9,
147.3, 148.5, 148.9, 159.1, 161.0 ppm; 19F NMR (470 MHz, CDCl3):
AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 0.7, 1.7, 2.0, 124.2, 125.2,
125.9,128.5,128.7,130.4,131.4,131.7,133.4,134.8,136.1,142.4,146.3,
147.3, 147.5, 147.9 ppm; IR (KBr, cmꢁ1) 3442, 2960, 1614, 1257; MS
(EI): m/z (%)¼493 (42, [MþH]þ), 478 (100); HRMS (EI): [MþH]þ,
found: 493.1116. C25H28ClNO2Si3 requires 493.1118.
d
ꢁ112.7 (m, AreF) ppm; IR (KBr, cmꢁ1) 3442, 2957, 1613, 1251; MS
(EI): m/z (%)¼437 (67, [MþH]þ), 57 (100); HRMS (EI): [MþH]þ,
found: 437.0834. C23H21ClFNOSi2 requires 437.0837.
4.1.1.7. 2,3-Oxadisilole-acridine (5g). Yield: 10.5 mg, 17%; yellow
4.1.1.13. 2,3-Dioxatrisilole-7-nitro-9-phenyl acridine (6d). Yield:
13.1 mg,13%; deep yellow solid; mp 171e172 ꢀC; 1H NMR (500 MHz,
powder; mp 79e81 ꢀC; 1H NMR (500 MHz, CDCl3):
d 0.47 (s, 6H,
SiMe2), 0.48 (s, 6H, SiMe2), 7.56 (t, J¼8.0 Hz, 1H, AreH), 7.79e7.82
(m, 1H, AreH), 8.03 (d, J¼8.0 Hz, 1H, AreH), 8.25 (s, 1H, AreH), 8.28
(d, J¼8.0 Hz, 1H, AreH), 8.49 (s, 1H, AreH), 8.82 (s, 1H, AreH) ppm;
CDCl3): d 0.14 (s, 6H, SiMe2), 0.33 (s, 6H, SiMe2), 0.55 (s, 6H, SiMe2),
7.48e7.49 (m, 2H, AreH), 7.68e7.69 (m, 3H, AreH), 7.99 (s, 1H,
AreH), 8.38 (d, J¼9.5 Hz, 1H, AreH), 8.48 (s, 1H, AreH), 8.50 (s, 1H,
AreH), 8.78 (d, J¼2.5 Hz, 1H, AreH) ppm; 13C NMR (125 MHz,
13C NMR (125 MHz, CDCl3):
d 1.0,1.2,125.9,126.6,126.9,128.3,129.1,
130.8, 131.7, 132.1, 136.9, 143.4, 148.4, 149.1, 149.3 ppm; IR (KBr,
cmꢁ1) 3048, 2957, 1667, 1252; MS (EI): m/z (%)¼310 (100, [MþH]þ);
HRMS (EI): [MþH]þ, found: 310.1078. C17H19NOSi2 requires
310.1076.
CDCl3): d 0.7, 1.6, 1.9, 123.1, 123.8, 124.5, 124.9, 128.8, 129.5, 130.4,
131.5, 133.6, 133.8, 136.0, 143.6, 144.9, 149.7, 149.9, 150.1, 151.1 ppm;
IR (KBr, cmꢁ1) 3442, 2959, 1623, 1258; MS (EI): m/z (%)¼504 (41,
[MþH]þ), 489 (100); HRMS (EI): [MþH]þ, found: 504.1357.
C25H28N2O4Si3 requires 504.1359.
4.1.1.8. 2,3-Oxadisilole-7-chloro-acridine (5h). Yield: 29.5 mg,
43%; dark yellow solid; mp 96e98 ꢀC; 1H NMR (500 MHz, CDCl3):
4.1.1.14. 2,3-Dioxatrisilole-9-(4-fluoro phenyl)-acridine (6e). Yield:
d
0.47 (s, 12H, SiMe2), 7.71 (dd, J¼9.0, 2.5 Hz, 1H, AreH), 8.00 (d,
17.2 mg, 18%; yellow powder; mp 151e153 ꢀC; 1H NMR (500 MHz,

5826
J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
CDCl3):
d
0.14 (s, 6H, SiMe2), 0.33 (s, 6H, SiMe2), 0.55 (s, 6H, SiMe2),
J¼8.5 Hz, 1H, AreH), 8.18 (d, J¼8.5 Hz, 1H, AreH), 8.27 (s, 1H, AreH),
8.93 (s, 1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
22.1, 124.4,
124.5, 125.5, 126.0, 126.3, 126.7, 128.2, 128.4, 128.5, 129.2, 130.6, 131.3,
133.6, 134.1, 135.0, 136.3, 144.6, 146.4, 149.0 ppm; IR (KBr, cmꢁ1) 3440,
3051, 1648, 1536; MS (EI): m/z (%)¼319 (1, [MþH]þ), 57 (100); HRMS
(EI): [MþH]þ, found: 320.1434. C24H17N requires 320.1435.
7.31e7.35 (m, 2H, AreH), 7.42e7.47 (m, 3H, AreH), 7.73 (d, J¼8.5 Hz,
1H, AreH), 7.77e7.80 (m, 1H, AreH), 7.91 (s, 1H, AreH), 8.29 (d,
J¼8.5 Hz, 1H, AreH), 8.48 (s, 1H, AreH) ppm; 13C NMR (125 MHz,
d
CDCl3):
d
0.7, 1.7, 2.0, 115.5 (d, J¼21.3 Hz), 124.1, 125.7, 126.0, 126.6,
129.7, 130.3, 131.3 (d, J¼3.8 Hz), 132.2 (d, J¼8.8 Hz), 133.2,136.1, 141.8,
146.0, 147.0, 147.8, 149.3, 161.8, 163.8 ppm; 19F NMR (470 MHz,
CDCl3):
d
ꢁ112.9 (s, AreF) ppm; IR (KBr, cmꢁ1) 3438, 2958, 1621,
4.1.1.20. 12-Phenyl-benzo[b]acridine (10b). Yield: 41.5 mg, 68%;
yellow brown powder; mp 220e222 ꢀC; 1H NMR (500 MHz, CDCl3):
1258; MS (EI): m/z (%)¼477 (31, [MþH]þ), 462 (100); HRMS (EI):
[MþH]þ, found: 477.1412. C25H28FNO2Si3 requires 477.1414.
d
7.33e7.38 (m, 1H, AreH), 7.43e7.46 (m, 1H, AreH), 7.51e7.53 (m,
1H, AreH), 7.65 (s, 1H, AreH), 7.66 (s, 1H, AreH), 7.69e7.71 (m, 1H,
AreH), 7.73e7.74 (m, 1H, AreH), 7.83 (d, J¼8.5 Hz, 1H, AreH), 8.08
(d, J¼8.5 Hz, 1H, AreH), 8.25 (d, J¼8.5 Hz, 1H, AreH), 8.33 (s, 1H,
4.1.1.15. 2,3-Dioxatrisilole-7-chloro-9-(2-fluoro phenyl)-acridine
(6f). Yield: 21.5 mg, 21%; pale yellow powder; mp 169e170 ꢀC;
1H NMR (500 MHz, CDCl3):
d
0.13 (s, 3H, SiMe2), 0.14 (s, 3H, SiMe2),
AreH), 8.94 (s, 1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 124.3,
0.31 (s, 3H, SiMe2), 0.33 (s, 3H, SiMe2), 0.548 (s, 3H, SiMe2), 0.551 (s,
3H, SiMe2), 7.36e7.40 (m, 2H, AreH), 7.41e7.44 (m, 1H, AreH),
7.61e7.65 (m, 1H, AreH), 7.66 (s, 1H, AreH), 7.71 (dd, J¼9.0, 2.5 Hz,
1H, AreH), 7.83 (s, 1H, AreH), 8.24 (d, J¼9.0 Hz, 1H, AreH), 8.46 (s,
124.5, 125.2, 125.5, 126.2, 126.4, 127.0, 128.2, 128.45, 128.51, 128.6,
129.7, 130.3, 130.6, 131.3, 134.3, 136.2, 145.3, 147.6, 150.1 ppm; IR
(KBr, cmꢁ1) 3441, 3051, 1681, 1487; MS (EI): m/z (%)¼305 (100,
[MþH]þ); HRMS (EI): [MþH]þ, found: 305.1204. C23H15N requires
305.1205.
1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 0.69, 0,71, 1.6, 1.7, 2.0,
116.2 (d, J¼21.3 Hz), 122.3 (d, J¼16.3 Hz), 124.3, 124.4 (d, J¼3.8 Hz),
124.7, 126.1, 128.8, 131.3 (d, J¼8.8 Hz), 131.6 (d, J¼3.8 Hz), 132.2,
132.4 (d, J¼2.5 Hz), 132.8, 136.2, 140.0, 143.0, 147.5, 147.9, 159.0,
4.1.1.21. 2-Chloro-12-phenyl-benzo[b]acridine (10c). Yield: 40.0
mg, 59%; deep red powder; mp 188e190 ꢀC; 1H NMR (500 MHz,
CDCl3): d 7.38e7.40 (m, 1H, AreH), 7.45e7.48 (m, 1H, AreH), 7.50 (d,
161.0 ppm; 19F NMR (470 MHz, CDCl3):
d
ꢁ112.5 (d, J¼6.5 Hz, AreF)
ppm; IR (KBr, cmꢁ1) 3446, 2960, 1613, 1256; MS (EI): m/z (%)¼511
J¼2.0 Hz, 1H, AreH), 7.52 (d, J¼2.0 Hz, 1H, AreH), 7.63 (d, J¼8.5 Hz,
1H, AreH), 7.66e7.69 (m, 4H, AreH), 7.84 (d, J¼8.5 Hz, 1H, AreH),
8.07 (d, J¼8.5 Hz,1H, AreH), 8.18 (d, J¼8.5 Hz,1H, AreH), 8.29 (s,1H,
(73, [MþH]þ), 496 (100); HRMS (EI): [MþH]þ, found: 511.1022.
C
25H27ClFNO2Si3 requires 511.1020.
AreH), 8.90 (s, 1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 124.3,
4.1.1.16. 2,3-Dioxatrisilole-acridine (6g). Yield: 10.0 mg, 13%;
124.5, 125.0, 125.9, 126.2, 126.7, 127.2, 128.3, 128.6, 128.75, 128.77,
130.5, 131.2, 131.5, 131.6, 131.7, 134.5, 135.6, 145.3, 146.8, 148.2 ppm;
IR (KBr, cmꢁ1) 3443, 3046, 1681, 1529; MS (EI): m/z (%)¼339 (100,
[MþH]þ); HRMS (EI): [MþH]þ, found: 339.0815. C23H14ClN requires
339.0816.
yellow solid; mp 55e56 ꢀC; 1H NMR (500 MHz, CDCl3):
d 0.16 (s, 6H,
SiMe2), 0.54 (s, 6H, SiMe2), 0.55 (s, 6H, SiMe2), 7.54e7.57 (m, 1H,
AreH), 7.79e7.83 (m, 1H, AreH), 8.01 (d, J¼8.5 Hz, 1H, AreH), 8.21
(s, 1H, AreH), 8.28 (d, J¼8.5 Hz, 1H, AreH), 8.49 (s, 1H, AreH), 8.78
(s,1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 0.7, 2.0, 2.03,125.6,
126.0, 127.1, 128.4, 128.8, 129.0, 130.9, 132.3, 135.0, 142.0, 147.7,
148.0, 149.1 ppm; IR (KBr, cmꢁ1) 3441, 2959, 1623, 1257; MS (EI): m/
z (%)¼384 (16, [MþH]þ), 321 (100); HRMS (EI): [MþH]þ, found:
384.1266. C19H25NO2Si3 requires 384.1274.
4.1.1.22. 2-Nitro-12-phenyl
37.1 mg, 53%; bronzing powder; mp 261e263 ꢀC; 1H NMR
(500 MHz, CDCl3): 7.42e7.45 (m, 1H, AreH), 7.50e7.53 (m, 1H,
benzo[b]acridine
(10d). Yield:
d
AreH), 7.56e7.58 (m, 2H, AreH), 7.73e7.74 (m, 3H, AreH), 7.87 (d,
J¼8.5 Hz,1H, AreH), 8.07 (d, J¼8.5 Hz,1H, AreH), 8.27 (d, J¼10.0 Hz,
1H, AreH), 8.36e8.38 (m, 2H, AreH), 8.71 (d, J¼2.0 Hz, 1H, AreH),
4.1.1.17. 2,3-Dioxatrisilole-7-chloro-acridine (6h). Yield: 19.2 mg,
13%; dark yellow solid; mp 112e113 ꢀC; 1H NMR (500 MHz, CDCl3):
8.90 (s, 1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 122.2, 122.8,
d
0.15 (s, 6H, SiMe2), 0.536 (s, 6H, SiMe2), 0.542 (s, 6H, SiMe2),7.71
124.2, 125.5, 126.4, 127.2, 127.5, 127.7, 128.2, 128.8, 128.9, 129.5,
130.6, 131.7, 132.0, 134.6, 135.6, 144.4, 146.5, 149.8, 152.4 ppm; IR
(KBr, cmꢁ1) 3442, 3048, 1619, 1333; MS (EI): m/z (%)¼350 (100,
[MþH]þ); HRMS (EI): [MþH]þ, found: 350.1055. C23H14N2O2 re-
quires 350.1058.
(dd, J¼9.0, 2.5 Hz,1H, AreH), 7.99 (d, J¼2.5 Hz, 1H, AreH), 8.18e8.19
(m, 2H, AreH), 8.42 (s, 1H, AreH), 8.66 (s, 1H, AreH) ppm; 13C NMR
(125 MHz, CDCl3):
d 0.7, 2.00, 2.03, 125.9, 126.4, 127.3, 131.2, 131.7,
131.8, 134.8, 135.0, 135.9, 142.7, 147.8, 147.9, 148.3 ppm; IR (KBr,
cmꢁ1) 2957, 2851, 1609, 1255; MS (EI): m/z (%)¼418 (100, [MþH]þ);
HRMS (EI): [MþH]þ, found: 418.0876. C19H24ClNO2Si3 requires
418.0889.
4.1.1.23. 12-(4-Fluoro-phenyl)-benzo[b]acridine (10e). Yield: 48.5
mg, 75%; reddish brown powder; mp 190e192 ꢀC; 1H NMR
(500 MHz, CDCl3):
d 7.37e7.44 (m, 4H, AreH), 7.48e7.53 (m, 3H,
4.1.1.18. 2,3-Dioxatrisilole-9-methyl-acridine (6i). Yield: 31.1 mg,
29%; yellow powder; mp 184e186 ꢀC; 1H NMR (500 MHz, CDCl3):
AreH), 7.69 (d, J¼8.5 Hz, 1H, AreH), 7.77e7.80 (m, 1H, AreH), 7.87
(d, J¼8.5 Hz, 1H, AreH), 8.10 (d, J¼8.5 Hz, 1H, AreH), 8.31 (s, 1H,
AreH), 8.35 (d, J¼8.5 Hz, 1H, AreH), 9.03 (s, 1H, AreH) ppm; 13C
d
0.16 (s, 6H, SiMe2), 0.54 (s, 6H, SiMe2), 0.56 (s, 6H, SiMe2), 3.14 (s,
3H, CH3), 7.55e7.58 (m,1H, AreH), 7.76e7.79 (m,1H, AreH), 8.23 (d,
J¼8.5 Hz, 1H, AreH), 8.26 (dd, J¼8.5, 0.5 Hz, 1H, AreH), 8.42 (d,
J¼0.5 Hz, 1H, AreH), 8.47 (s, 1H, AreH) ppm; 13C NMR (125 MHz,
NMR (125 MHz, CDCl3):
d
115.8 (d, J¼21.3 Hz), 124.4, 124.6, 125.5,
125.8 (d, J¼16.3 Hz), 126.6, 126.7, 127.0, 128.3, 128.6, 129.7, 130.4,
131.5, 132.0, 132.3 (d, J¼8.8 Hz), 134.4, 145.2, 146.5, 150.0, 162.0,
CDCl3):
d
0.8, 2.06, 2.10, 13.3, 124.4, 124.6, 125.6, 126.2, 130.0, 130.2,
163.9 ppm; 19F NMR (470 MHz, CDCl3):
d
ꢁ113.1 (s, AreF) ppm; IR
131.1, 136.8, 141.2, 142.3, 146.5, 147.5, 148.8 ppm; IR (KBr, cmꢁ1
)
(KBr, cmꢁ1) 3446, 3046, 1601, 1510; MS (EI): m/z (%)¼323 (100,
[MþH]þ); HRMS (EI): [MþH]þ, found: 323.1110. C23H14FN requires
323.1114.
3423, 2955, 1623, 1251; MS (EI): m/z (%)¼398 (11, [MþH]þ), 382
(100); HRMS (EI): [MþH]þ, found: 398.1422. C20H27NO2Si3 requires
398.1424.
4.1.1.24. 2-Chloro-12-(2-fluoro-phenyl)-benzo[b]acridine
(10f). Yield: 44.3 mg, 62%; reddish brown powder; mp 242e243 ꢀC;
4.1.1.19. 2-Methyl-12-phenyl-benzo[b]acridine (10a). Yield: 30.1
mg, 47%; red brown powder; mp 144e145 ꢀC; 1H NMR (500 MHz,
1H NMR (500 MHz, CDCl3):
d 7.40e7.50 (m, 5H, AreH), 7.61 (s, 1H,
CDCl3):
d
2.44 (s, 3H, CH3), 7.35e7.37 (m, 1H, AreH), 7.41e7.45 (m, 2H,
AreH), 7.66e7.71 (m, 2H, AreH), 7.86 (d, J¼8.5 Hz, 1H, AreH), 8.09
AreH), 7.51e7.52 (m, 2H, AreH), 7.57 (d, J¼9.5 Hz, 1H, AreH),
(d, J¼8.5 Hz, 1H, AreH), 8.25e8.27 (m, 2H, AreH), 8.96 (s, 1H, AreH)
7.66e7.67 (m, 3H, AreH), 7.82 (d, J¼8.5 Hz, 1H, AreH), 8.07 (d,
ppm; 13C NMR (125 MHz, CDCl3):
d
116.4 (d, J¼21.3 Hz), 122.9 (d,

J. Zhang et al. / Tetrahedron 70 (2014) 5820e5827
5827
ꢀ
6. (a) Carole, D. G.; Michel, D. M.; Julien, C.; Florence, D.; Anna, N.; Severine, J.;
J¼16.3 Hz),124.2,124.5,124.6 (d, J¼3.8 Hz),124.9,125.5,126.2,126.9,
127.2, 128.3, 128.5, 131.3 (d, J¼8.8 Hz), 131.8, 132.0 (d, J¼8.8 Hz),
132.5 (d, J¼2.5 Hz), 134.7, 141.0, 144.7, 147.8, 159.1, 161.1 ppm; 19F
ꢀ
Gerard, D.; Pierre, T. D.; Galy, J. P. Bioorg. Med. Chem. 2005, 13, 5560e5568; (b)
Giorgio, C. D.; Shimi, K.; Boyer, G.; Delmas, F.; Galy, J. P. Eur. J. Med. Chem. 2007,
42, 1277e1284.
NMR (470 MHz, CDCl3):
d
ꢁ112.7 (m, AreF) ppm; IR (KBr, cmꢁ1
)
7. (a) Demeunynck, M.; Charmantray, F.; Martelli, A. Curr. Pharm. Des. 2001, 7,
1703e1724; (b) Kusuzaki, K.; Murata, H.; Matsubara, T.; Satonaka, H.; Waka-
bayashi, T.; Matsumine, A.; Uchida, A. In Vivo 2007, 21, 205e214; (c) Oppegard,
L. M.; Ougolkov, A. V.; Luchini, D. N.; Schoon, R. A.; Goodell, J. R.; Kaur, H.;
Billadeau, D. D.; Hiasa, H. Eur. J. Pharmacol. 2009, 602, 223e229; (d) Kapuriya,
N.; Kapuriya, K.; Zhang, X.; Chou, T. C.; Kakadiya, R.; Wu, Y. T.; Tsai, T. H.; Chen,
Y. T.; Lee, T. C.; Shah, A.; Naliapara, Y.; Su, T. L. Bioorg. Med. Chem. 2008, 16,
5413e5423; (e) Luan, X.; Gao, C.; Zhang, N.; Chen, Y.; Sun, Q.; Tan, C.; Liu, H.; Jin,
Y.; Jiang, Y. Bioorg. Med. Chem. 2011, 19, 3312e3319; (f) Goodell, J. R.; Ougolkov,
A. V.; Hiasa, H.; Kaur, H.; Remmel, R.; Billadeau, D. D.; Ferguson, D. M. J. Med.
Chem. 2007, 51, 179e182; (g) Ghosh, R.; Bhowmik, S.; Guha, D. Mol. Cell. Bio-
chem. 2012, 361, 55e66.
8. Cahoon, J. M.; Olson, P. R.; Nielson, S. Exp. Eye Res. 2014, 120, 15e19.
9. (a) Katritzky, A. R.; Barczynski, P.; Musumarra, G.; Pisano, D.; Szafran, M. J. Am.
Chem. Soc. 1989, 111, 7e15; (b) Shanmugasundaram, P.; Prabahar, K. J.; Ram-
akrishnan, V. T. J. Heterocycl. Chem. 1993, 30, 1003e1007; (c) Islam, A.; Murugan,
P.; Hwang, K. C.; Cheng, C. H. Synth. Met. 2003, 139, 347e353.
3442, 3068, 1637, 1614; MS (EI): m/z (%)¼358 (100, [MþH]þ); HRMS
(EI): [MþH]þ, found: 358.0793. C23H13ClFN requires 358.0798.
4.1.1.25. Benzo[b]acridine (10g). Yield: 19.3 mg, 42%; brown
powder; mp 82e84 ꢀC; 1H NMR (500 MHz, CDCl3):
d 7.62e7.65 (m,
1H, AreH), 7.67e7.70 (m, 1H, AreH), 7.73e7.76 (m, 1H, AreH),
7.83e7.86 (m, 1H, AreH), 7.92 (d, J¼8.5 Hz, 1H, AreH), 7.98e8.00
(m, 1H, AreH), 8.06 (d, J¼8.5 Hz, 1H, AreH), 8.12 (d, J¼8.5 Hz, 1H,
AreH), 8.32 (d, J¼8.5 Hz, 1H, AreH), 8.77 (d, J¼8.5 Hz, 1H, AreH),
9.46 (s, 1H, AreH) ppm; 13C NMR (125 MHz, CDCl3):
d 122.9, 124.2,
126.3, 126.5, 127.6, 127.9, 128.3, 128.4, 128.5, 128.9, 129.8, 130.5,
131.1, 131.2, 133.1, 147.5, 148.8 ppm; IR (KBr, cmꢁ1) 3439, 2920, 1615,
1502; MS (EI): m/z (%)¼230 (20, [MþH]þ), 229 (100); HRMS (EI):
[MþH]þ, found: 230.0964. C17H11N requires 230.0965.
10. (a) Mohan, H.; Srividya, N.; Ramamurthy, P.; Mittal, J. P. J. Phys. Chem. 1997, 101,
2931e2935; (b) Srividya, N.; Ramamurthy, P.; Ramakrishnan, V. T. Spectrochim.
Acta, Part A 1998, 54, 245e253; (c) Mohan, H.; Mittal, J. P.; Srividya, N.; Ram-
amurthy, P. J. Phys. Chem. 1998, 102, 4444e4449.
11. Srividya, N.; Ramamurthy, P.; Shanmugasundaram, P.; Ramakrishnan, V. T. J. Org.
Chem. 1996, 61, 5083e5089.
Acknowledgements
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Financial support from the National Natural Science Foundation
of China (nos. 21272146 and 20872086) is gratefully acknowledged.
Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2014.06.031.
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