Multicomponent approach for the synthesis of phenanthridine and acridine ring systems via the coupling of fischer carbene complexes with hetero-aromatic o-alkynyl carbonyl derivatives

Article abstract of DOI:10.1055/s-0030-1258180

A one-pot multicomponent synthesis of phenanthridine and acridine derivatives is described. This method includes the in situ generation of furo[3,4-c]isoquinoline and furo[3,4-b]quinoline intermediates by the coupling of heteroaromatic o-alkynyl carbonyl derivatives with Fischer carbene complexes and subsequent trapping of these intermediates by suitable dienophiles. Georg Thieme Verlag Stuttgart - New York.

Full text of DOI:10.1055/s-0030-1258180

PAPER
3179
Multicomponent Approach for the Synthesis of Phenanthridine and Acridine
Ring Systems via the Coupling of Fischer Carbene Complexes with Hetero-
aromatic o-Alkynyl Carbonyl Derivatives
Multicomponent
S
o
ynthesis of
P
u
henanthridin
r
e
and
A
c
ridine
D
eri
n
vatives ga P. Jana, Soumita Mukherjee, Binay K. Ghorai*
Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711103, India
Fax +91(33)26682916; E-mail: bkghorai@yahoo.co.in
Received 5 May 2010; revised 21 May 2010
details of the multicomponent coupling approach for the
Abstract: A one-pot multicomponent synthesis of phenanthridine
and acridine derivatives is described. This method includes the in
situ generation of furo[3,4-c]isoquinoline and furo[3,4-b]quinoline
intermediates by the coupling of heteroaromatic o-alkynyl carbonyl
synthesis of phenanthridine derivatives, along with the
synthesis of acridine derivatives, using Fischer carbene
chemistry. This process involves the first-time generation
derivatives with Fischer carbene complexes and subsequent trap- of furo[3,4-c]isoquinoline and furo[3,4-b]quinoline inter-
mediates by the coupling of Fischer carbene complexes7
ping of these intermediates by suitable dienophiles.
with heteroaromatic o-alkynyl carbonyl derivatives.
These intermediates can actively participate in inter- and
intramolecular cycloaddition reactions. Hence, our syn-
thetic strategy includes the generation of the furo[3,4-
c]isoquinoline intermediates 3 formed by the coupling of
o-alkynylisoquinolinecarbonyl derivatives 1 with Fischer
carbene complex 2 and of the furo[3,4-b]quinoline inter-
mediates 7 formed by the coupling of o-alkynylquinolin-
ecarbonyl derivatives 5 with Fischer carbene complex 6,
and trapping of these intermediates using suitable dieno-
philes for the synthesis of phenanthridine and acridine de-
rivatives (Scheme 1).
Key words: azaisobenzofuran, heterocycles, Diels–Alder reaction,
chromium, carbene complexes
Fused azaheterocycles are a family of biological agents
with particularly interesting pharmacological properties
related to the planarity of the system. Substituted phenan-
thridines and acridines are important classes of heterocy-
clic compounds in medicinal chemistry and are attractive
synthetic targets due to their widespread occurrence in na-
ture and broad range of biological activity including anti-
tumor and antiviral activity.1 A large number of acridine
drugs, natural alkaloids or synthetic molecules, have been
tested as antibacterial and antimalarial agents.2 Classical
synthetic methods for these heterocyclic molecules in-
volve multistep condensation reactions resulting in the de-
sired azaheterocycles;3,4 however, many synthetic routes
require harsh conditions and thus appear to be unsuitable
for the synthesis of functionalized heterocycles incorpo-
rating sensitive functional groups. In multistep reactions,
the limited substrate scope and the frequent requirement
of harsh reaction conditions, with extremely high temper-
atures, limit the usefulness and generality of these meth-
ods. This has led to the search for new synthetic methods
that would facilitate the preparation of an appropriate se-
ries of compounds. Thus, a synthesis suitable for both of
these heterocyclic compounds and also their analogues is
required. As a contrast to this multistep strategy, a new
concept for the synthesis of a target compound with a
higher chemical efficiency is emerging. Multicomponent
reactions (MCRs) are responsible for this higher efficien-
cy.5 MCRs provide a complementary approach to a num-
ber of structures and should find applications in library
generation. In a preliminary communication, we de-
scribed the synthesis of phenanthridine ring systems using
the MCR approach.6 In this paper, we wish to report full
The requisite 3-alkynylisoquinoline-4-carbonyl deriva-
tives necessary for our study were readily prepared using
the series of reactions depicted in Scheme 2. 3-Chloro-1-
phenylisoquinoline-4-carbaldehyde (10) was prepared
from dihydroisoquinolinone 98 by a two-step procedure
involving a Vilsmeier–Haack reaction followed by oxida-
tion with potassium permanganate under acidic condi-
tions.9 The Sonogashira coupling of chloride 10 with
(trimethylsilyl)acetylene afforded 1-phenyl-3-(trimethyl-
silylethynyl)isoquinoline-4-carbaldehyde (11), which on
treatment with the appropriate Grignard reagent and sub-
sequent oxidation with pyridinium dichromate resulted in
the ketones 12–14.
Similarly, the corresponding quinoline derivative 1610
was prepared by the palladium-catalyzed Sonogashira re-
action of 3-formyl-2-iodoquinoline (15)11 with (trimethyl-
silyl)acetylene (Scheme 3). Exposure of aldehyde 16 to an
aryl or alkyl Grignard reagent in diethyl ether followed by
pyridinium dichromate oxidation resulted in the alkynyl
carbonyl derivatives 17–19.
In the first phase of these studies, a three-component cou-
pling reaction of carbene complex 2, 3-alkynylisoquino-
line-4-carbaldehyde 11 and dimethyl maleate in refluxing
tetrahydrofuran was carried out, which on exposure to sil-
ica gel led to the synthesis of the phenanthridine deriva-
tive 21 (Scheme 4). Formation of compound 21 occurs
through the generation of the transient furo[3,4-c]isoquin-
oline intermediate 20, followed by Diels–Alder reaction
SYNTHESIS 2010, No. 18, pp 3179–3187
x
x.
x
x
.
2
0
1
0
Advanced online publication: 16.07.2010
DOI: 10.1055/s-0030-1258180; Art ID: Z11810SS
© Georg Thieme Verlag Stuttgart · New York

3180
G. P. Jana et al.
PAPER
E
N
Cr(CO)5
R1
R1
E
E
E
R1
O
N
OMe
O
TMS
OMe
1.
2
TMS
N
THF, reflux
2. silica gel
O
Ph
Ph
Ph
1
3
4
O
R2
R2
O
OH
Cr(CO)5
R2
THF, reflux
silica gel
MeO
+
N
N
N
TMS
TMS
TMS
OMe
O
5
6
7
8
Scheme 1 Tandem generation and trapping of furo[3,4-c]isoquinoline and furo[3,4-b]quinoline intermediates
R1
O
N
TMS
CHO
TMS
CHO
O
Cl
b
c
a
NH
N
N
Ph
Ph
Ph
Ph
12 R1 = Ph
9
10
11
13 R1 = CH2(CH2)2CH=CH2
14 R1 = CH2(CH2)3CH=CH2
Scheme 2 Synthesis of isoquinolines substituted with an aldehyde or a ketone group. Reagents and conditions: (a) POCl3, DMF, THF, 0 °C;
then KMnO4, H2SO4, r.t., 42%; (b) (trimethylsilyl)acetylene, (Ph3P)2PdCl2, Ph3P, CuI, Et3N, THF, r.t., 67%; (c) (i) R1MgBr; (ii) CrO3·2py, 12
(72%), 13 (52%), 14 (47%).
O
CHO
CHO
R2
a
b
N
N
N
I
TMS
TMS
17 R2 = Ph
15
16
18 R2 = p-Tol
19 R2 = (CH2)3CH=CH2
Scheme 3 Synthesis of functionalized quinolines. Reagents and conditions: (a) (trimethylsilyl)acetylene, (Ph3P)2PdCl2, CuI, Et3N, THF, r.t.,
86%; (b) (i) R2MgBr; (ii) CrO3·2py, 17 (70%), 18 (69%), 19 (45%).
with the dimethyl maleate present in the reaction mixture. imide as dienophile, the phenanthridine derivative 24 was
When N-methylmaleimide was used as the dienophile, isolated as the only product (Scheme 4).
however, the [4+2] oxa-bridged adduct 22 could be isolat-
The tandem generation and intramolecular trapping of fu-
ed together with the phenanthridine derivative 23. The
ro[3,4-c]isoquinoline and furo[3,4-b]quinoline intermedi-
chemical shift values of the HB and HC protons (<4 ppm),
ates was studied using unactivated alkenyl tethers of
various length. The reaction of carbene complex 2 with
ketone 13 bearing an unactivated alkenyl tether afforded a
the 0-Hz coupling between HA and HB, and the N–Me sig-
nal (~3.0 ppm)7a,12 confirm the exo stereochemistry of the
oxa-bridged adduct 22. This oxa-bridged adduct 22 was
mixture of the oxa-bridged adduct 27 and the [1,7]-hydro-
converted into the phenanthridine derivative 23 on treat-
gen-shift product 29 (Scheme 5). Interestingly, under sim-
ment with 1,8-diazabicyclo[5.4.0]undec-7-ene in reflux-
ilar reaction conditions, no intramolecular cycloaddition
ing toluene.13 In contrast, in the analogous coupling of 11
leading to the oxa-bridged adduct 28 was obtained when
the dienophile tether to the ketone was increased by one
with carbene complex 2 in the presence of N-phenylmale-
Synthesis 2010, No. 18, 3179–3187 © Thieme Stuttgart · New York

PAPER
Multicomponent Synthesis of Phenanthridine and Acridine Derivatives
3181
H
OMe
O
CHO
TMS
O
Cr(CO)5
OMe
THF, reflux
N
O
Ph
1.
TMS
+
N
N
Ph
Ph
2. H3O+
20
2
11
CO2Me
CO2Me
O
N
O
Ph
O
N
1.
Me
1.
O
CO2Me
CO2Me
2. silica gel
2. H3O+
N
O
N
Ph
24, 39%
O
Ph
Me
HC
O
Me
O
O
N
N
HB
HA
O
21, 44%
O
N
+
N
O
O
Ph
Ph
DBU, toluene, reflux
22, 30%
23, 32%
Scheme 4 Synthesis of phenanthridine derivatives
n
n
O
OMe
O
TMS
Cr(CO)5
THF, reflux
24 h
TMS
+
OMe
N
N
2
Ph
Ph
25, n = 1
26, n = 2
13, n = 1
14, n = 2
n
n
H
O
silica gel
O
H
O
+
H
N
N
O
Ph
Ph
27, n = 1, 20%
28, n = 2, 0%
29, n = 1, 32%
30, n = 2, 47%
Scheme 5 Generation and Diels–Alder trapping of furo[3,4-c]isoquinoline intermediates using an intramolecular approach
methylene unit (i.e., ketone 14). In this reaction, the [1,7]- form the [1,7]-hydrogen-shift products 29/30, respective-
hydrogen-shift product 30 was the only product isolated ly.7a,14 In contrast, the reaction of carbene complex 2 with
from the reaction mixture. Formation of the [1,7]-hydro- alkynylquinolinyl ketone 19 bearing an unactivated alke-
gen-shift products 29/30 suggests either (i) that unactivat- nyl tether, under the same reaction conditions, gave exclu-
ed dienophile lowers the rate of the Diels–Alder step of sively the alcohol 32 with no [1,7]-hydrogen-shift product
the tandem reaction process, or (ii) that the furo[3,4-c]iso- (Scheme 6).
quinoline intermediates 25/26 can directly hydrolyze to
Synthesis 2010, No. 18, 3179–3187 © Thieme Stuttgart · New York

3182
G. P. Jana et al.
PAPER
similar reaction with carbene complexes 6/39 which led to
acridine derivatives 41–44 through the generation of the
furo[3,4-b]quinoline intermediates 40 (Scheme 8).
Cr(CO)5
OMe
O
THF, reflux
24 h
+
N
In summary, we have developed a convenient one-pot
synthesis of phenanthridine and acridine ring systems by
the coupling of Fischer carbene complexes with hetero-
aromatic o-alkynyl carbonyl derivatives, with the genera-
tion of reactive furo[3,4-c]isoquinoline and furo[3,4-
b]quinoline intermediates.
TMS
19
2
HO
silica gel
Melting points were determined on a Sunbim melting point appara-
tus and are uncorrected. IR spectra were recorded neat or as KBr
O
N
N
discs on a Jasco FT/IR-460 Plus spectrometer. H and 13C NMR
OMe
TMS
1
O
spectra were recorded using tetramethylsilane as internal reference
on Bruker AC 400, DRX 500, DPX 300, Avance 600 and
UltraShield™ 500 spectrometers (chemical shift values in d, J in
Hz). Mass spectra were obtained using an Agilent 6120 mass spec-
trometer.
32, 43%
31
Scheme 6 Generation and intramolecular Diels–Alder trapping of a
furo[3,4-b]quinoline intermediate
1-Phenyl-3-(trimethylsilylethynyl)isoquinoline-4-carbaldehyde
(11)
The reaction process was also tested using a g,d-unsatur-
ated Fischer carbene complex. The coupling of monopre-
nylated carbene complex 6 with alkynyl carbonyl
derivatives 11/12 under the same conditions as previously
described underwent intramolecular Diels–Alder reaction
through the generation of the furo[3,4-c]isoquinoline in-
termediates 33/34 leading to the tetracyclic skeletons 37/
38, respectively (Scheme 7). The initial Diels–Alder ad-
ducts 35/36, resulting from 33/34, appear to be unstable
with respect to the ring-opening process.15 Compounds 37
A mixture of 3-chloro-1-phenylisoquinoline-4-carbaldehyde (10;
1.34 g, 5.0 mmol), (Ph3P)2PdCl2 (0.176 g, 0.25 mmol), Ph3P (33 mg,
0.125 mmol), (trimethylsilyl)acetylene (736 mg, 7.5 mmol) and
Et3N (759 mg, 7.5 mmol) in THF (20 mL) was stirred at r.t. for 20
min, and then CuI (10 mg, 0.05 mmol) was added. The reaction
mixture was stirred at r.t. for 16 h, then the solvent was removed on
a rotary evaporator. The residue was treated with CH2Cl2 (10 mL)
and the mixture was filtered through Celite®. The filtrate was con-
centrated and the residue was purified by silica gel column chroma-
tography (EtOAc–petroleum ether, 1:9) to afford alkyne 11.
and 38, bearing the tetracyclic skeleton, are aza analogues Yield: 1.1 g (67%); white solid; mp 126 °C; Rf = 0.69 (EtOAc–
petroleum ether, 1:9).
IR (KBr): 2155, 1686 cm–1.
of tetracyclic triterpenes. Thus, the reaction may be useful
for the synthesis of analogues of natural products.
1H NMR (400 MHz, CDCl3): d = 11.04 (s, 1 H), 9.33 (d, J = 8.5 Hz,
1 H), 8.08 (d, J = 8.4 Hz, 1 H), 7.86 (td, J = 7.8, 1.0 Hz, 1 H), 7.73–
7.66 (m, 2 H), 7.60 (t, J = 7.7 Hz, 1 H), 7.57–7.50 (m, 3 H), 0.30 (s,
9 H).
The intramolecular trapping of transient furo[3,4-b]quin-
oline intermediates was also studied by using carbene
complex 6 and its bisprenylated species 39.16 The o-alk-
ynylquinolinecarbonyl derivatives 16/17/1810 underwent
R1
R1
O
N
O
TMS
+
OMe
Cr(CO)5
OMe
THF, reflux
TMS
N
24 h
Ph
Ph
33 R1 = H
6
34 R1 = Ph
11 R1 = H
12 R1 = Ph
HO
R1
R1
O
silica gel
OMe
O
N
TMS
N
TMS
Ph
Ph
35 R1 = H
37 R1 = H, 48%
38 R1 = Ph, 55%
36 R1 = Ph
Scheme 7 Synthesis of phenanthridines using a monoprenylated Fischer carbene complex
Synthesis 2010, No. 18, 3179–3187 © Thieme Stuttgart · New York

PAPER
Multicomponent Synthesis of Phenanthridine and Acridine Derivatives
3183
R2
O
Cr(CO)5
R2
THF, reflux
24 h
O
+
OMe
N
R3
N
R3
TMS
TMS
OMe
16 R2 = H
6 R3 = H
17 R2 = Ph
39 R3 = CH2CH=CH2
18 R2 = p-Tol
40
R2
R2
OH
R2
OH
OH
silica gel
N
N
N
R3
R3
TMS
R3
O
O
OMe
43 R2 = H, R3 = CH2CH=CH2, 51%
41 R2 = H, R3 = H, 42%
42 R2 = Ph, R3 = H, 43%
44 R2 = p-Tol, R3 = CH2CH=CH2, 55%
Scheme 8 Synthesis of acridines using mono-/bisprenylated Fischer carbene complexes
13C NMR (125 MHz, CDCl3): d = 194.3, 166.2, 143.3, 138.3, 133.6,
133.1, 130.0 (2 C), 129.5, 128.4 (3 C), 128.3, 126.1, 125.0, 124.9,
103.6, 100.8, –0.3 (3 C).
MS: m/z (%) = 406 (100) [M + H]+.
Anal. Calcd for C27H23NOSi: C, 79.96; H, 5.72; N, 3.45. Found: C,
79.73; H, 5.59; N, 3.57.
MS: m/z (%) = 330 (100) [M + H]+, 258 (10).
1-[1-Phenyl-3-(trimethylsilylethynyl)isoquinolin-4-yl]hex-5-en-
1-one (13)
Yield: 0.412 g (52%); thick liquid; Rf = 0.78 (EtOAc–petroleum
Anal. Calcd for C21H19NOSi: C, 76.56; H, 5.81; N, 4.25. Found: C,
76.21; H, 5.72; N, 4.02.
ether, 1:4).
IR (neat): 2157, 1702 cm–1.
Alkynyl(iso)quinolinecarbonyl Derivatives; General Procedure
To a stirred soln of aldehyde (2 mmol) in anhyd Et2O (10 mL) was
added dropwise a soln of aryl-/alkylmagnesium bromide (2.2
mmol) in anhyd Et2O [prepared from aryl/alkyl bromide (3 mmol)
and magnesium (4 mmol) in anhyd Et2O (10 mL)] over a period of
20 min at 0 °C. After being stirred for 3 h, the mixture was allowed
to warm to r.t. and the reaction was then quenched with sat. aq
NH4Cl (5 mL). The organic layer was separated and the aqueous
layer was extracted with Et2O (3 × 10 mL). The combined organic
layer was washed with brine (5 mL) and dried (Na2SO4). The sol-
vent was removed under reduced pressure and the crude alcohol
was used in the next step.
1H NMR (400 MHz, CDCl3): d = 8.05 (d, J = 8.4 Hz, 1 H), 7.71 (d,
J = 3.6 Hz, 2 H), 7.67–7.61 (m, 2 H), 7.59–7.47 (m, 4 H), 5.83 (m,
1 H), 5.06 (d, J = 17.2 Hz, 1 H), 5.01 (d, J = 10.0 Hz, 1 H), 3.15 (t,
J = 7.5 Hz, 2 H), 2.21 (q, J = 6.8 Hz, 2 H), 1.94 (pentet, J = 7.5 Hz,
2 H), 0.25 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 206.2, 162.1, 138.5, 137.7, 136.1,
132.9, 131.3 (2 C), 130.9, 129.9 (2 C), 129.0, 128.3, 128.2, 128.1,
125.8, 124.0, 115.4, 102.3, 100.2, 43.9, 33.2, 22.9, –0.36 (3 C).
MS: m/z (%) = 399 (35) [MH+ + 1], 398 (100) [M + H]+.
A soln of the crude alcohol in anhyd CH2Cl2 (2 mL) was added to a
red soln of CrO3·2py [prepared from a vigorously stirred suspension
of CrO3 (6 mmol) and pyridine (12 mmol) in anhyd CH2Cl2 (12 mL)
at r.t. for 1.5 h] and the mixture was stirred at r.t. for 4 h. The mix-
ture was then diluted with Et2O (10 mL) and passed through a bed
of silica gel (5 g). The solution was then concentrated under reduced
pressure and purified by silica gel column chromatography
(EtOAc–petroleum ether, 2:8).
Anal. Calcd for C26H27NOSi: C, 78.54; H, 6.84; N, 3.52. Found: C,
78.71; H, 6.65; N, 3.68.
1-[1-Phenyl-3-(trimethylsilylethynyl)isoquinolin-4-yl]hept-6-
en-1-one (14)
Yield: 0.386 g (47%); thick liquid; Rf = 0.47 (EtOAc–petroleum
ether, 1:9).
IR (neat): 2158, 1701, 1640 cm–1.
1H NMR (400 MHz, CDCl3): d = 8.07 (d, J = 8.5 Hz, 1 H), 7.73–
7.67 (m, 2 H), 7.66–7.61 (m, 2 H), 7.63–7.42 (m, 4 H), 5.82 (m, 1
H), 5.03 (dd, J = 17.0, 1.0 Hz, 1 H), 4.97 (d, J = 10.0 Hz, 1 H), 3.16
(t, J = 7.5 Hz, 2 H), 2.13 (q, J = 7.0 Hz, 2 H), 1.86 (pentet, J = 7.5
Hz, 2 H), 1.55 (pentet, J = 7.5 Hz, 2 H), 0.26 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 206.3, 162.1, 138.5, 138.3, 136.1,
132.9, 131.3, 130.9, 129.9 (2 C), 129.0, 128.3 (2 C), 128.2, 128.1,
125.8, 124.0, 114.8, 102.3, 100.2, 44.5, 33.6, 28.6, 23.2, –0.36 (3
C).
Phenyl[1-phenyl-3-(trimethylsilylethynyl)isoquinolin-4-
yl]methanone (12)
Yield: 0.583 g (72%); white solid; mp 117–119 °C; Rf = 0.43
(EtOAc–petroleum ether, 1:9).
IR (KBr): 2160, 1666 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.13 (d, J = 8.5 Hz, 1 H), 7.97 (d,
J = 8.0 Hz, 2 H), 7.74 (d, J = 8.5 Hz, 1 H), 7.72 (d, J = 8.0 Hz, 2 H),
7.67 (t, J = 7.5 Hz, 1 H), 7.63 (t, J = 7.5 Hz, 1 H), 7.60–7.52 (m, 4
H), 7.49 (t, J = 7.5 Hz, 2 H), –0.06 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 196.2, 162.3, 138.6, 137.1, 134.4,
133.9, 133.9, 132.4, 131.3, 130.0 (4 C), 129.0, 128.7 (2 C), 128.3 (2
C), 128.2, 128.1, 125.8, 124.6, 102.4, 101.3, –0.77 (3 C).
MS: m/z (%) = 413 (30) [MH+ + 1], 412 (100) [M + H]+.
Anal. Calcd for C27H29NOSi: C, 78.79; H, 7.10; N, 3.40. Found: C,
78.57; H, 6.83; N, 3.54.
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G. P. Jana et al.
PAPER
Phenyl[2-(trimethylsilylethynyl)quinolin-3-yl]methanone (17)
Yield: 0.460 g (70%); thick yellow liquid; Rf = 0.60 (EtOAc–petro-
leum ether, 1:9).
IR (neat): 2180, 1668 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.36 (s, 1 H), 8.19 (d, J = 8.5 Hz,
1 H), 7.91–7.81 (m, 4 H), 7.68–7.61 (m, 2 H), 7.49 (t, J = 7.5 Hz, 2
H), 0.01 (s, 9 H).
Yield: 0.093 g (44%); white solid; mp 122 °C (dec); Rf = 0.30
(EtOAc–petroleum ether, 3:7).
IR (KBr): 1736, 1712 cm–1.
1H NMR (500 MHz, CDCl3): d = 9.24 (s, 1 H), 8.79 (d, J = 8.0 Hz,
1 H), 8.25 (d, J = 8.0 Hz, 1 H), 7.94 (t, J = 8.0 Hz, 1 H), 7.77–7.73
(m, 2 H), 7.72 (t, J = 8.0 Hz, 1 H), 7.60–7.53 (m, 3 H), 4.44 (s, 2 H),
4.02 (s, 3 H), 3.99 (s, 3 H), 2.22 (s, 3 H).
13C NMR (125 MHz, CDCl3): d = 195.3, 148.4, 138.4, 136.6, 133.5,
131.4, 130.2 (2 C), 129.4, 128.8, 128.5 (2 C), 128.1 (2 C), 127.9,
126.3, 102.2, 101.8, –0.7 (3 C).
13C NMR (125 MHz, CDCl3): d = 205.6, 169.3, 166.3, 162.9, 143.8,
139.2, 134.5, 134.0, 133.5, 131.3, 130.1 (2 C), 129.2, 129.1, 128.3
(3 C), 125.7, 125.3, 124.6, 123.5, 122.8, 52.8 (2 C), 43.7, 30.0.
MS: m/z (%) = 331 (30) [MH+ + 1], 330 (100) [M + H]+, 268 (20).
MS: m/z (%) = 450 (11) [M + Na]+, 428 (100) [M + H]+, 396 (58).
Anal. Calcd for C21H19NOSi: C, 76.56; H, 5.81; N, 4.25. Found: C,
76.31; H, 5.92; N, 4.10.
HRMS: m/z [M + Na]+ calcd for C26H21NNaO5: 450.1317; found:
450.1311.
1-[2-(Trimethylsilylethynyl)quinolin-3-yl]hex-5-en-1-one (19)
Yield: 0.288 g (45%); thick yellow liquid; Rf = 0.35 (EtOAc–petro-
leum ether, 1:9).
Compounds 22 and 23 by the Coupling of Carbene Complex 2
with 1-Phenyl-3-(trimethylsilylethynyl)isoquinoline-4-carbal-
dehyde (11) and N-Methylmaleimide
IR (neat): 2158, 1703 cm–1.
Compound 22
1H NMR (500 MHz, CDCl3): d = 8.35 (s, 1 H), 8.13 (d, J = 8.5 Hz,
1 H), 7.86 (d, J = 8.5 Hz, 1 H), 7.79 (td, J = 8.5, 1.0 Hz, 1 H), 7.59
(td, J = 8.5, 1.0 Hz, 1 H), 5.81 (m, 1 H), 5.04 (dd, J = 17.0, 1.2 Hz,
1 H), 4.99 (dd, J = 10.5, 1.2 Hz, 1 H), 3.23 (t, J = 7.0 Hz, 2 H), 2.17
(q, J = 7.0 Hz, 2 H), 1.88 (pentet, J = 7.0 Hz, 2 H), 0.31 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 202.5, 148.5, 139.4, 137.8, 136.5,
135.6, 131.7, 129.2, 128.4, 128.1, 126.3, 115.4, 103.0, 100.4, 41.7,
33.1, 23.6, –0.3 (3 C).
Yield: 0.124 g (30%); white solid; mp 171 °C (dec); Rf = 0.25
(EtOAc–petroleum ether, 3:7).
IR (KBr): 1703 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.18 (d, J = 8.5 Hz, 1 H), 7.97 (d,
J = 8.5 Hz, 1 H), 7.79 (t, J = 7.5 Hz, 1 H), 7.66 (d, J = 6.5 Hz, 2 H),
7.60–7.49 (m, 4 H), 6.18 (s, 1 H), 3.85 (d, J = 17.2 Hz, 1 H), 3.49
(d, J = 17.2 Hz, 1 H), 3.30 (d, J = 6.5 Hz, 1 H), 3.14 (d, J = 6.5 Hz,
1 H), 3.07 (s, 3 H), 2.30 (s, 3 H).
13C NMR (125 MHz, CDCl3): d = 203.2, 175.6, 174.6, 160.8, 158.1,
139.1, 131.1, 130.6, 130.3 (2 C), 130.2, 128.9 (2 C), 128.3 (2 C),
127.2, 125.7, 122.8, 87.9, 78.7, 51.1, 50.2, 41.3, 31.4, 25.2.
MS: m/z (%) = 323 (20) [MH+ + 1], 322 (70) [M + H]+, 279 (28),
261 (15), 260 (100).
Anal. Calcd for C20H23NOSi: C, 74.72; H, 7.21; N, 4.36. Found: C,
74.51; H, 7.09; N, 4.49.
MS: m/z (%) = 435 (10) [M + Na]+, 413 (100) [M + H]+, 302 (90),
260 (9).
Coupling of Carbene Complex 2 with Alkynylisoquinolinecar-
baldehyde 11 and Maleimides/Dimethyl Maleate; General Pro-
cedure
HRMS: m/z [M + H]+ calcd for C25H21N2O4: 413.1501; found:
413.1492.
To a refluxing soln of alkynyl aldehyde 11 (1 mmol) and a maleim-
ide or dimethyl maleate (1 mmol) in THF (5 mL) was added a soln
of carbene complex 2 (1.1 mmol) in THF (10 mL) over a period of
1 h. After the addition was complete, the mixture was heated to re-
flux for a period of 12 h. The mixture was allowed to cool to r.t. and
was concentrated on a rotary evaporator. EtOAc (20 mL) was added
and the mixture was filtered through Celite® (1.0 g). The solvent
was removed on a rotary evaporator, and the crude product was dis-
solved in Et2O (20 mL).
Compound 23
Yield: 0.126 g (32%); white solid; mp 203 °C (dec); Rf = 0.55
(EtOAc–petroleum ether, 3:7).
IR (KBr): 1759, 1713 cm–1.
1H NMR (500 MHz, CDCl3): d = 9.03 (s, 1 H), 8.80 (d, J = 8.5 Hz,
1 H), 8.20 (d, J = 8.5 Hz, 1 H), 7.97 (t, J = 8.0 Hz, 1 H), 7.80–7.70
(m, 3 H), 7.62–7.50 (m, 3 H), 4.99 (s, 2 H), 3.25 (s, 3 H), 2.42 (s, 3
H).
To this solution of crude product in Et2O was added aq HCl (1:1, 0.5
mL) and the mixture was stirred at r.t. for 6 h. The organic layer was
separated. The aqueous layer was neutralized with sat. NaHCO3
soln (3 mL) and extracted with EtOAc (3 × 10 mL). The combined
organic layer (Et2O layer and EtOAc extracts) was washed with
H2O (3 mL) and brine (3 mL), and dried (Na2SO4). Evaporation of
solvent and purification of the residue by chromatography gave the
pure products.
13C NMR (125 MHz, CDCl3): d = 205.6, 168.7, 168.1, 162.4, 145.2,
139.1, 135.7, 134.0, 131.5, 130.1 (2 C), 129.3, 129.1, 128.9, 128.6,
128.3 (2 C), 128.2, 127.1, 125.5, 123.2, 117.2, 41.0, 30.8, 24.2.
MS: m/z (%) = 395 (100) [M + H]+.
Anal. Calcd for C25H18N2O3: C, 76.13; H, 4.60; N, 7.10. Found: C,
76.01; H, 4.79; N, 6.94.
9-Methyl-7-(2-oxopropyl)-5-phenyl-6,9-diaza-8H-cyclopen-
ta[b]phenanthrene-8,10(9H)-dione (23)
Compound 21 by the Coupling of Carbene Complex 2 with
1-Phenyl-3-(trimethylsilylethynyl)isoquinoline-4-carbaldehyde
(11) and Dimethyl Maleate
The general procedure above was followed using alkynyl aldehyde
11 (165 mg, 0.50 mmol), dimethyl maleate (72 mg, 0.50 mmol) and
carbene complex 2 (138 mg, 0.55 mmol). The only exception was
that, instead of HCl treatment, the crude product was dissolved in
CHCl3 (20 mL) and stirred with silica gel (2 g) for 6 h. The solvent
was evaporated and the residue was purified by silica gel column
chromatography.
To a stirred soln of oxa-bridged compound 22 (21 mg, 0.05 mmol)
in toluene (3 mL), DBU (76 mg, 0.5 mmol) was added dropwise at
r.t. The mixture was heated to reflux for 1.5 h. After being cooled to
r.t., the mixture was washed with 10% aq HCl (1.0 mL) and dried
(Na2SO4). After evaporation of the solvent, the crude product was
purified by preparative thin-layer silica gel chromatography
(EtOAc–petroleum ether, 1:1) to give aromatized product 23 as a
yellow solid; yield: 8 mg (42%).
Synthesis 2010, No. 18, 3179–3187 © Thieme Stuttgart · New York

PAPER
Multicomponent Synthesis of Phenanthridine and Acridine Derivatives
3185
Compound 24 by the Coupling of Carbene Complex 2 with 1-
Phenyl-3-(trimethylsilylethynyl)isoquinoline-4-carbaldehyde
(11) and N-Phenylmaleimide
13C NMR (125 MHz, CDCl3): d = 197.2, 164.9, 164.0, 144.7, 138.8,
137.9, 132.4, 131.6, 131.1, 130.3, 130.2 (2 C), 129.7, 129.3, 128.5
(2 C), 127.6, 123.4, 115.3, 97.7, 86.5, 34.4, 33.3, 31.2, 23.8.
Yield: 0.178 g (39%); white solid; mp 216 °C; Rf = 0.38 (EtOAc–
petroleum ether, 3:7).
IR (KBr): 1767, 1712 cm–1.
1H NMR (500 MHz, CDCl3): d = 9.14 (s, 1 H), 8.82 (d, J = 8.0 Hz,
1 H), 8.28 (d, J = 8.0 Hz, 1 H), 7.97 (td, J = 7.5, 1.0 Hz, 1 H), 7.81–
7.74 (m, 3 H), 7.63–7.57 (m, 3 H), 7.56–7.49 (m, 4 H), 7.43 (t,
J = 7.5 Hz, 1 H), 5.05 (s, 2 H), 2.43 (s, 3 H).
MS: m/z (%) = 370 (100) [M + H]+, 330 (35).
HRMS: m/z [M + Na]+ calcd for C25H23NNaO2: 392.1626; found:
392.1625.
Compound 30 by the Coupling of Carbene Complex 2 with
1-[1-Phenyl-3-(trimethylsilylethynyl)isoquinolin-4-yl]hept-
6-en-1-one (14)
Yield: 0.180 g (47%); yellow solid; mp 144–145 °C; Rf = 0.24
(EtOAc–petroleum ether, 1:4).
IR (KBr): 1625, 1581 cm–1.
13C NMR (125 MHz, CDCl3): d = 205.4, 167.6, 166.9, 162.7, 145.5,
139.1, 136.4, 134.0, 131.8, 131.6, 130.1 (2 C), 129.4, 129.2, 129.1
(2 C), 129.0, 128.4 (2 C), 128.2, 128.1, 127.7, 127.6, 126.7 (2 C),
125.6, 123.3, 117.9, 41.1, 30.8.
1H NMR (500 MHz, CDCl3): d = 8.25 (d, J = 8.5 Hz, 1 H), 7.90 (d,
J = 8.5 Hz, 1 H), 7.84 (t, J = 7.5 Hz, 1 H), 7.76–7.70 (m, 2 H), 7.66
(t, J = 7.5 Hz, 1 H), 7.60–7.50 (m, 3 H), 6.32 (s, 1 H), 6.19 (dd,
J = 7.5, 2.5 Hz, 1 H), 5.76 (m, 1 H), 4.98 (d, J = 17.5 Hz, 1 H), 4.93
(d, J = 10.5 Hz, 1 H), 2.47 (s, 3 H), 2.46 (m, 1 H), 2.10–2.00 (m, 3
H), 1.55–1.41 (m, 4 H).
13C NMR (150 MHz, CDCl3): d = 197.1, 164.9, 163.9, 144.6, 138.7,
138.4, 132.4, 131.5, 131.0, 130.1 (2 C), 129.6, 129.2, 128.5, 128.4
(2 C), 127.5, 123.3, 114.7, 97.6, 86.6, 34.9, 33.4, 31.2, 28.6, 24.1.
MS: m/z (%) = 458 (33) [MH+ + 1], 457 (100) [M + H]+.
Anal. Calcd for C30H20N2O3: C, 78.93; H, 4.42; N, 6.14. Found: C,
78.71; H, 4.67; N, 6.31.
Coupling of Carbene Complex 2 with Alkynyl(iso)quinolinecar-
bonyl Derivatives; General Procedure
To a refluxing soln of an alkynyl carbonyl derivative 13/14/19 (1
mmol) in THF (10 mL) was added a soln of carbene complex 2 (1.1
mmol) in THF (10 mL) over a period of 1 h. After the addition was
complete, the mixture was heated to reflux for a period of 24 h. The
mixture was allowed to cool to r.t. and was concentrated on a rotary
evaporator. EtOAc (20 mL) was added and the mixture was filtered
through Celite® (1.0 g). The solvent was removed on a rotary evap-
orator, and the crude product was dissolved in CHCl3 (20 mL) and
stirred with silica gel (2 g) at r.t. for 6 h. Evaporation of solvent and
purification of the residue by chromatography gave the pure prod-
ucts.
MS: m/z (%) = 384 (100) [M + H]+, 366 (7), 344 (8), 326 (9).
HRMS: m/z [M + Na]+ calcd for C26H25NNaO2: 406.1783; found:
406.1782.
Compound 32 by the Coupling of Carbene Complex 2 with
1-[2-(Trimethylsilylethynyl)quinolin-3-yl]hex-5-en-1-one (19)
Yield: 0.125 g (43%); gummy solid; Rf = 0.42 (EtOAc–petroleum
ether, 1:3).
IR (neat): 3430, 1638 cm–1.
Compounds 27 and 29 by the Coupling of Carbene Complex 2
with 1-[1-Phenyl-3-(trimethylsilylethynyl)isoquinolin-4-yl]hex-
5-en-1-one (13)
1H NMR (500 MHz, CDCl3): d = 8.11 (d, J = 8.5 Hz, 1 H), 8.10 (s,
1 H), 7.83 (s, 1 H), 7.82 (d, J = 8.5 Hz, 1 H), 7.72 (td, J = 7.5, 1.3
Hz, 1 H), 7.55 (td, J = 7.5, 1.3 Hz, 1 H), 3.69 (m, 1 H), 3.06 (ddd,
J = 19.0, 12.5, 3.0 Hz, 1 H), 2.43 (s, 3 H), 2.16–2.08 (m, 3 H), 2.09–
1.90 (m, 4 H), 1.79 (m, 1 H).
13C NMR (125 MHz, CDCl3): d = 199.6, 152.3, 149.7, 147.5, 136.4,
131.8, 129.8 (2 C), 128.1, 127.5, 127.3, 125.1, 78.3, 44.1, 35.9,
32.7, 28.4, 27.7, 21.5.
Compound 27
Yield: 0.074 g (20%); gummy solid; Rf = 0.55 (EtOAc–petroleum
ether, 1:4).
IR (neat): 1707 cm–1.
1H NMR (400 MHz, CDCl3): d = 8.14 (d, J = 8.4 Hz, 1 H), 8.08 (d,
J = 8.4 Hz, 1 H), 7.72–7.62 (m, 3 H), 7.57–7.40 (m, 4 H), 3.59 (d,
J = 14.8 Hz, 1 H), 3.35 (d, J = 14.8 Hz, 1 H), 2.97 (m, 1 H), 2.43 (m,
1 H), 2.26 (s, 3 H), 2.20–2.02 (m, 4 H), 1.98–1.80 (m, 2 H), 1.69 (m,
1 H).
MS: m/z (%) = 295 (20) [MH+ + 1], 294 (100) [M + H]+, 276 (20).
Anal. Calcd for C19H19NO2: C, 77.79; H, 6.53; N, 4.77. Found: C,
77.84; H, 6.62; N, 4.89.
Coupling of Mono-/Bisprenylated Carbene Complexes 6/39
with Alkynyl(iso)quinolinecarbonyl Derivatives; General Pro-
cedure
13C NMR (125 MHz, CDCl3): d = 206.3, 160.0, 159.2, 139.8, 131.1,
130.6, 130.3 (2 C), 130.1, 128.9, 128.5, 128.3 (2 C), 125.9, 125.7,
122.3, 97.6, 86.2, 48.8, 44.9, 39.9, 31.9, 31.6, 29.6, 27.1.
To a soln of an alkynyl carbonyl derivative 11/12/16/17/18 (1
mmol) in THF (5 mL) at reflux was added a soln of a g,d-unsatur-
ated carbene complex 6/39 (1.1 mmol) in THF (10 mL) over a peri-
od of 1 h. After the addition was complete, the mixture was heated
to reflux for 24 h. The mixture was cooled to r.t. The THF was re-
moved under reduced pressure, EtOAc (10 mL) was added and the
mixture was filtered through Celite® (1.0 g). After evaporation of
the solvent, the crude product was purified by column chromatog-
raphy.
MS: m/z (%) = 370 (100) [M + H]+, 352 (40) [MH+ – H2O], 312
(20).
HRMS: m/z [M + H]+ calcd for C25H24NO2: 370.1807; found:
370.1801.
Compound 29
Yield: 0.118 g (32%); yellow solid; mp 135–136 °C; Rf = 0.25
(EtOAc–petroleum ether, 1:4).
IR (KBr): 1635, 1623 cm–1.
Compound 37 by the Coupling of Carbene Complex 6 with
1-Phenyl-3-(trimethylsilylethynyl)isoquinoline-4-carbaldehyde
(11)
Yield: 0.198 g (48%); white solid; mp 168–169 °C; Rf = 0.25
(EtOAc–petroleum ether, 3:7).
1H NMR (500 MHz, CDCl3): d = 8.23 (d, J = 8.4 Hz, 1 H), 7.88 (d,
J = 8.4 Hz, 1 H), 7.83 (t, J = 7.5 Hz, 1 H), 7.75–7.68 (m, 2 H), 7.65
(t, J = 7.5 Hz, 1 H), 7.59–7.50 (m, 3 H), 6.32 (s, 1 H), 6.19 (dd,
J = 7.5, 2.2 Hz, 1 H), 5.75 (m, 1 H), 5.01 (d, J = 17.2 Hz, 1 H), 4.98
(d, J = 14.4 Hz, 1 H), 2.46 (s, 3 H), 2.42 (m, 1 H), 2.20–2.10 (m, 2
H), 2.00 (m, 1 H), 1.75–1.48 (m, 2 H).
IR (KBr): 3374, 1630 cm–1.
Synthesis 2010, No. 18, 3179–3187 © Thieme Stuttgart · New York

3186
G. P. Jana et al.
PAPER
1H NMR (500 MHz, CDCl3): d = 8.60 (d, J = 8.5 Hz, 1 H), 8.00 (d,
J = 8.5 Hz, 1 H), 7.82 (t, J = 8.5 Hz, 1 H), 7.72–7.57 (m, 3 H), 7.57–
7.50 (m, 3 H), 5.77 (t, J = 7.0 Hz, 1 H), 2.80 (m, 1 H), 2.70 (ddd,
J = 15.0, 11.0, 4.5 Hz, 1 H), 2.56 (dt, J = 17.0, 3.5 Hz, 1 H), 2.38
(ddd, J = 17.0, 15.0, 4.5 Hz, 1 H), 2.24 (m, 1 H), 2.00 (s, 1 H, ex-
changeable with D2O), 1.92 (m, 1 H), 1.87 (m, 1 H), 0.0 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 203.1, 165.8, 160.6, 146.1, 141.5,
138.6, 135.4, 130.5, 129.9 (2 C), 129.2, 128.6, 128.3, 128.1 (2 C),
127.8, 127.6, 125.2, 66.0, 41.5, 37.6, 36.8, 28.2, 2.01 (3 C).
13C NMR (125 MHz, CDCl3): d = 200.1, 155.8, 149.4, 147.8, 145.8,
137.1, 135.2, 130.3, 130.0, 128.7, 128.4 (2 C), 128.0, 127.8, 127.7,
126.8 (2 C), 125.0, 75.5, 46.6, 37.7, 33.4, 30.2.
MS: m/z (%) = 343 (30) [MH+ + 1], 342 (100) [M + H]+, 322 (20).
Anal. Calcd for C23H19NO2: C, 80.92; H, 5.61; N, 4.10. Found: C,
80.74; H, 5.73; N, 3.98.
Compound 43 by the Coupling of Carbene Complex 39 with
2-(Trimethylsilylethynyl)quinoline-3-carbaldehyde (16)
Yield: 0.192 g (51%); gummy solid; Rf = 0.51 (EtOAc–petroleum
ether, 3:7).
MS: m/z (%) = 436 (100) [M + Na]+, 414 (60) [M + H]+, 398 (8).
Anal. Calcd for C26H27NO2Si: C, 75.51; H, 6.58; N, 3.39. Found: C,
75.27; H, 6.32; N, 3.51.
IR (neat): 3437, 1640 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.39 (s, 1 H), 8.11 (d, J = 8.5 Hz,
1 H), 7.84 (d, J = 8.5 Hz, 1 H), 7.73 (t, J = 8.5 Hz, 1 H), 7.56 (t,
J = 8.5 Hz, 1 H), 5.84 (m, 1 H), 5.15 (m, 1 H), 5.10 (d, J = 6.0 Hz,
1 H), 5.07 (s, 1 H), 2.86 (m, 1 H), 2.60–2.53 (m, 2 H), 2.45 (ddd,
J = 12.5, 5.5, 4.0 Hz, 1 H), 2.21–2.14 (m, 2 H), 2.08–2.01 (m, 2 H),
1.91 (q, J = 12.5 Hz, 1 H), 0.16 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 205.9, 161.4, 152.4, 146.7, 143.1,
136.5, 134.5, 134.2, 130.0, 129.1, 128.3, 127.7, 127.4, 116.6, 68.5,
44.4, 41.2, 34.1, 33.4, 33.2, 2.37 (3 C).
Compound 38 by the Coupling of Carbene Complex 6 with
Phenyl[1-phenyl-3-(trimethylsilylethynyl)isoquinolin-4-yl]meth-
anone (12)
Yield: 0.270 g (55%); white solid; mp >220 °C (dec); Rf = 0.2
(EtOAc–petroleum ether, 1:9).
IR (KBr): 3447, 1636 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.11 (dd, J = 8.0, 2.0 Hz, 1 H),
7.85 (dd, J = 8.0, 2.0 Hz, 1 H), 7.58–7.50 (m, 5 H), 7.45–7.40 (m, 2
H), 7.33–7.27 (m, 5 H), 2.70 (m, 1 H), 2.67 (s, 1 H, exchangeable
with D2O), 2.51 (d, J = 12.0 Hz, 1 H), 2.43 (d, J = 17.5 Hz, 1 H),
2.34–2.20 (m, 2 H), 1.88 (m, 1 H), 1.68 (m, 1 H), –0.03 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 203.4, 165.4, 161.2, 146.4, 146.0,
142.5, 138.5, 134.9, 132.0, 129.8 (2 C), 129.7, 128.7, 128.6 (2 C),
128.3 (3 C), 128.0 (2 C), 127.5, 127.4, 126.1 (2 C), 76.2, 52.4, 36.7,
35.6, 27.7, 2.4 (3 C).
MS: m/z (%) = 379 (30) [MH+ + 1], 378 (100) [M + H]+, 363 (20),
362 (60).
Anal. Calcd for C23H27NO2Si: C, 73.17; H, 7.21; N, 3.71. Found: C,
73.12; H, 7.11; N, 3.83.
Compound 44 by the Coupling of Carbene Complex 39 with
p-Tolyl[2-(trimethylsilylethynyl)quinolin-3-yl]methanone (18)
Yield: 0.256 g (55%); gummy solid; Rf = 0.28 (EtOAc–petroleum
ether, 1:9).
MS: m/z (%) = 491 (42) [MH+ + 1], 490 (100) [M + H]+.
HRMS: m/z [M + H]+ calcd for C32H32NO2Si: 490.2202; found:
490.2194.
IR (neat): 3435, 1639 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.19 (s, 1 H), 8.17 (d, J = 8.0 Hz,
1 H), 7.76 (d, J = 8.0 Hz, 1 H), 7.75 (t, J = 7.5 Hz, 1 H), 7.55 (t,
J = 7.5 Hz, 1 H), 7.11 (d, J = 8.0 Hz, 2 H), 7.05 (d, J = 8.0 Hz, 2 H),
5.73 (m, 1 H), 4.94 (d, J = 10.0 Hz, 1 H), 4.87 (d, J = 17.1 Hz, 1 H),
2.74 (m, 1 H), 2.53–2.45 (m, 4 H), 2.33 (s, 3 H), 2.31 (q, J = 12.5
Hz, 1 H), 2.07 (m, 1 H), 2.01–1.90 (m, 2 H), 0.18 (s, 9 H).
Compound 41 by the Coupling of Carbene Complex 6 with
2-(Trimethylsilylethynyl)quinoline-3-carbaldehyde (16)
Yield: 0.116 g (42%); gummy solid; Rf = 0.57 (EtOAc–petroleum
ether, 3:7).
IR (neat): 3390, 1619 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.26 (s, 1 H), 8.16 (d, J = 3.0 Hz,
1 H), 8.15 (d, J = 3.0 Hz, 1 H), 7.83 (d, J = 8.0 Hz, 1 H), 7.70 (td,
J = 8.0, 1.0 Hz, 1 H), 7.52 (td, J = 8.0, 1.0 Hz, 1 H), 7.23 (d, J = 8.0
Hz, 1 H), 6.98 (dd, J = 8.0, 3.0 Hz, 1 H), 5.14 (m, 1 H), 3.96 (s, 3
H), 3.22 (dd, J = 15.0, 4.8 Hz, 1 H), 3.12 (dd, J = 15.0, 8.5 Hz, 1 H),
2.09 (br s, 1 H).
13C NMR (75 MHz, CDCl3): d = 159.3, 151.7, 147.8, 134.8, 132.9,
132.2, 130.0, 129.4, 129.3, 127.7, 127.6, 127.3, 126.3, 117.4, 109.6,
77.2, 68.5, 36.9.
13C NMR (125 MHz, CDCl3): d = 206.1, 161.6, 152.7, 146.9, 143.5
(2 C), 137.6 (2 C), 136.4, 135.3, 130.3, 129.1, 129.0 (2 C), 128.4,
128.0, 127.4, 126.5 (2 C), 116.5, 75.7, 48.0, 44.6, 34.1, 33.3, 32.1,
21.0, 2.51 (3 C).
MS: m/z (%) = 469 (40) [MH+ + 1], 468 (100) [M + H]+, 463 (25),
452 (75).
Anal. Calcd for C30H33NO2Si: C, 77.05; H, 7.11; N, 2.99. Found:
C, 77.31; H, 7.22; N, 2.81.
MS: m/z (%) = 279 (25) [MH+ + 1], 278 (100) [M + H]+, 261 (10),
260 (60).
Acknowledgment
Anal. Calcd for C18H15NO2: C, 77.96; H, 5.45; N, 5.05. Found: C,
77.85; H, 5.61; N, 4.96.
Financial support from CSIR [No. 01 (2215)/08-EMR-II], Govern-
ment of India is gratefully acknowledged. We thank CPIPL, Kolka-
ta and IICB, Kolkata for providing the NMR facility. The UGC,
New Delhi is also thanked for the award of a Junior Research Fel-
lowship to S.M.
Compound 42 by the Coupling of Carbene Complex 6 with Phe-
nyl[2-(trimethylsilylethynyl)quinolin-3-yl]methanone (17)
Yield: 0.146 g (43%); gummy solid; Rf = 0.33 (EtOAc–petroleum
ether, 3:7).
References
IR (neat): 3407, 1660 cm–1.
1H NMR (500 MHz, CDCl3): d = 8.43 (s, 1 H), 8.13 (d, J = 8.5 Hz,
1 H), 7.79 (d, J = 8.5 Hz, 1 H), 7.75 (td, J = 7.5, 1.0 Hz, 1 H), 7.64
(d, J = 2.0 Hz, 1 H), 7.55 (td, J = 7.5, 1.0 Hz, 1 H), 7.32–7.27 (m, 3
H), 7.13 (m, 2 H), 2.73 (s, 1 H), 2.60–2.49 (m, 3 H), 2.38 (ddd,
J = 17.0, 15.0, 5.0 Hz, 1 H), 2.17 (t, J = 12.5 Hz, 1 H), 2.06 (m, 1
H), 1.90 (m, 1 H).
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Synthesis 2010, No. 18, 3179–3187 © Thieme Stuttgart · New York