6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-Hexamethyldisilazane and Molecular Iodine

Article abstract of DOI:10.1002/ejoc.201901278

Warming treatment of aryl o-biaryl ketones with 1,1,1,3,3,3-hexamethyldisilazane in the presence of Sc(OTf)₃ in toluene, followed by the reaction with molecular iodine and K₂CO₃ in a mixture of THF and methanol at 60 °C gave the corresponding 6-arylphenanthridines in good to moderate yields. The present reaction is a one-pot method for the preparation of 6-arylphenanthridines from aryl o-biaryl ketones through the cyclization of imino-nitrogen-centered radicals that were generated from N-iodo aryl o-biaryl ketimines formed from the reaction of aryl biaryl ketimines with molecular iodine.

Full text of DOI:10.1002/ejoc.201901278

A Journal of
Accepted Article
Title: 6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-
Hexamethyldisilazane and Molecular Iodine
Authors: Eiji Kobayashi, Atsushi Kishi, and Hideo Togo
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To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.201901278
Link to VoR: http://dx.doi.org/10.1002/ejoc.201901278
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10.1002/ejoc.201901278
European Journal of Organic Chemistry
FULL PAPER
DOI: 10.1002/ejoc.200((will be filled in by the editorial staff))
6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-
Hexamethyldisilazane and Molecular Iodine
Eiji Kobayashi,[a] Atsushi Kishi,[a] and Hideo Togo*[a]
Keywords: 6-Arylphenanthridine / Ketone / Ketimine / Iodine / Iminyl Radical
Warming treatment of aryl o-biaryl ketones with 1,1,1,3,3,3- The present reaction is a one-pot method for the preparation of
hexamethyldisilazane in the presence of Sc(OTf)3 in toluene, 6-arylphenanthridines from aryl o-biaryl ketones through the
followed by the reaction with molecular iodine and K2CO3 in a cyclization of imino-nitrogen-centered radicals that were
mixture of THF and methanol at 60 °C gave the corresponding 6- generated from N-iodo aryl o-biaryl ketimines formed from the
arylphenanthridines in good to moderate yields.
reaction of aryl biaryl ketimines with molecular iodine.
____________
of dimethyl sulfoxide and water;4b the preparation of 6-
methylphenanthridines with (diacetoxyiodo)benzene (DIB), 2-
nitropropane, and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) in
acetonitrile;4c the preparation of 6-benzylphenanthridines with
toluene, Fe(acac)3, di-tert-butyl peroxide (DTBT);4d the
preparation of 6-(trifluoromethyl)phenanthridines with CF3SO2Na
and biacetyl under CFL irradiation;4e the preparation of 6-
(arenesulfonyl)phenanthridines with ArSO2Na, AgNO3, and
[a]
Graduate School of Science, Chiba University, Yayoi-cho 1-33,
Inage-ku, Chiba 263-8522 Japan
Fax: 81-43-290-2792
E-mail: togo@faculty.chiba-u.jp
Homepage: http://reaction-2.chem.chiba-u.jp/index.html
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/ejoc.xxxxxxxxx.
K2S2O8
in
DMF;4f
the
preparation
of
6-
Introduction
[(dimethyl)(cyano)methyl]phenanthridines
with
azo[bis(isobutyronitrile)] (AIBN) in toluene;4g the preparation of 6-
(perfluoroalkyl)phenanthridines with perfluoroalkyl iodides and
N,N,N’,N’-tetraethylethylenediamine in THF under CFL
irradiation;4h the preparation of 6-alkylphenanthridines with
aliphatic carboxylic acids, Ag2CO3, and K2S2O8 in a mixture of
acetonitrile and water;4i and the preparation of 6-
Phenanthridines are one of the important nitrogen-containing
heteroaromatics because natural products bearing phenanthridine
unit are known and phenanthridine derivatives show remarkable
biological activities, such as antitumor, antiviral, and antileukemic
activities.1 Typical biologically active phenanthridines, such as
trispheridine (DNA intercalator), decarine (DNA intercalator), and
ethidium (DNA stain), are shown in Fig. 1.2
arylphenanthridines
with
anilines
and
t-BuONO
in
benzotrifluoride.4j o-Isocyanobiaryls could be also used for the
preparation of 6-arylphenanthridines with arylbromides and Rh-6G
as the catalyst under irradiation with blue LED,5a and the
preparation of 6-aroylphenanthridines with 2-iodo-2’-isocyano-
1,1’-biphenyl, Pd(OAc)2, and CuI as catalysts.5b Other recent
synthetic approaches for the preparation of phenanthridines are
also reported. For example, the preparation of 6-phosphorylated
phenanthridines from 2-biaryl isothiocyanates, phosphine oxides,
and Mn(OAc)3 in DMF;6a the preparation of
6-
(trifluoromethyl)phenanthridines from N-aryl trifluoromethyl
imidoyl chlorides, aryl iodides, Pd(OAc)2, and norbornene in
toluene;6b the preparation of 6-arylphenanthridines from enediyne
acids, o-alkynylanilines, PdCl2, and CuI in DMF;6c the preparation
of 6-aryl- and 6-alkylphenanthridines from o-cyanobiaryl and
Grignard reagents, followed by the reaction with Cu(OAc)2 under
Fig. 1. Biologically Active Phenanthridines
O2;6d
the
preparation
of
CF3S-containing
ring-fused
Synthetic studies of the phenanthridine core have been carried
out extensively.3 Recently, the construction of 6-substituted
phenanthridines with o-isocyanobiaryls through the formation of
imino-carbon-centered radicals and their cyclization onto aromatic
rings has become popular (Scheme 1, eq. 1). Recent reports of the
construction of 6-substituted phenanthridines with o-
isocyanobiaryls via imino-carbon-centered radicals are as follows:4
the preparation of 6-[-(methoxycarbonyl)alkyl]phenanthridines
with Katritzky pyridinium salts in the presence of Ru(bpy)2Cl2 in
acetonitrile under LED irradiation conditions;4a the preparation of
phenanthridines from N-(o-cyanobiaryl)acrylamides and N-
(trifluoromethylthio)saccharins under visible light irradiation;6e the
preparation of 6-(trifluoromethyl)phenanthridines from 2-
bromophenylboronic acid, fluorinated imidoyl chlorides, and
PdCl2(Ph3P)2;6f and a related reaction for the preparation of
nitrogen-containing pyrenes with 2,6-dicyanobiphenyls and
Grignard reagents, followed by the reaction with Co(OAc)2 under
O26g are reported.
6-[dimethyl(trifluoromethyl)]methylphenanthridines
dimethyl(trifluoromethyl)]acetic acid and (NH4)2S2O8 in a mixture
with
On the other hand, to the best of our knowledge, studies of the
transformation of aryl biaryl ketones into 6-arylphenanthridines are
Submitted to the European Journal of Organic Chemistry
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10.1002/ejoc.201901278
European Journal of Organic Chemistry
quite limited, some examples of which are as follows (Scheme 1,
eq. 2)7: the preparation of 6-alkyl and 6-arylphenanthridines with
o-acylbiaryls, TMSN3, and TfOH in TFA at 60 °C;7a the
preparation of 6-unsubstituted phenanthridines with o-
biarylaldehydes, ArCO2NH2, and fac-Ir(ppy)3 in DMF under
visible light irradiation7b and with o-biarylaldehydes and NH3 in
(CF3)2CHOH (HFIP) and CH3OH under electrochemical
conditions.7c As indirect methods, the visible light irradiation of O-
acyl oximes derived from o-biaryl ketones in the presence of fac-
Ir(ppy)3 in DMF at 26 °C gave 6-alkyl and 6-arylphenanthridines,8a
and the electrochemical treatment of o-biaryl methyl ketone
Results and Discussion
The formation of diaryl ketimines in the reaction of diaryl
ketones with 1,1,1,3,3,3-hexamethyldisilazane in the presence of
Sc(OTf)3 as the catalyst in refluxing toluene is known.9 Practically,
treatment of o-(p-methylphenyl)phenyl phenyl ketone 1Aa (1.0
mmol) with 1,1,1,3,3,3-hexamethyldisilazane (2.0 equiv.) in the
presence of Sc(OTf)3 (0.2 equiv.) without solvent and in toluene
(1.0 mL) at 90 °C for 5 h (1st step) gave ketimine 2Aa in 88% and
90% yields, respectively. Based on those results, treatment of
ketone 1Aa (1.0 mmol) with 1,1,1,3,3,3-hexamethyldisilazane (2.0
equiv.) in the presence of Sc(OTf)3 (0.2 equiv.) without solvent and
in toluene (1.0 mL) at 90 °C for 5 h (1st step), followed by the
removal of the solvents and the subsequent treatment with
molecular iodine (1.5 equiv.) and K2CO3 (3.0 equiv.) in a mixture
of THF (4.0 mL) and water (4.0 mL) at 60 °C for 2 h (2nd step)
gave 3-methyl-6-phenylphenanthridine 3Aa in 47% and 53%
yields, together with ketone 1Aa in 47% and 35% yields,
respectively, as shown in Table 1 (entries 1 and 2). Here, ketone
1Aa was recovered by hydrolysis of ketimine 2Aa by quenching of
the reaction mixture with sat. aq. Na2SO3. Under the same
procedure and conditions, the warming treatment of ketimine 2Aa
with molecular iodine (1.5 equiv.) and K2CO3 (3.0 equiv.) in a
mixture of THF (4.0 mL) and MeOH (4.0 mL), and in MeOH (4.0
mL) at 60 °C for 2 h (2nd step) gave 3Aa in 63% and 59% yields,
together with ketone 1Aa in 33% and 18% yields, respectively
(entries 3, 4). Moreover, treatment of ketone 1Aa with 1,1,1,3,3,3-
hexamethyldisilazane (2.0 equiv.) in the presence of Sc(OTf)3 (0.2
equiv.) in toluene (1.0 mL) at 90 °C for 5 h and 15 h (1st step),
followed by removal of the solvent and the subsequent reaction
with molecular iodine (1.5 equiv.) and K2CO3 (3.0 equiv.) at 60 °C
for 2 h in a mixture of THF (2.0 mL) and MeOH (2.0 mL)(2nd step)
oximes
in
the
presence
of
TEMPO
gave
6-
methylphenanthridines.8b Those reactions8 proceed through the
formation of imino-nitrogen-centered radicals, followed by their
cyclization onto aromatic rings to form the phenanthridine core.
Based on our previous study for the preparation of 6-alkyl and 6-
arylphenanthridines from the reaction of o-cyanobiaryls with ArLi,
followed by the reaction with water and then molecular iodine,3 we
would like to report herein a one-pot transformation of aryl o-
biaryl ketones into 6-arylphenanthridines through the formation of
the corresponding aryl o-biaryl ketimines and the cyclization of the
formed imino-nitrogen-centered radicals onto the aromatic ring by
the treatment with molecular iodine, as shown in eq. 3 of Scheme 1.
Table 1. Optimization for Formation of 3-Methyl-6- phenylphenant
hridine 3Aa from o-(p-Methylphenyl)phenyl Phenyl ketone 1Aa.
time solvent1st
solvent2nd (mL)
yield
(%)
entry
(h)
(mL)
47(47)[a]
53(35)[a]
63(33)[a]
59(18)[a]
78
1
2
3
4
5
6
5
5
5
5
5
15
neat
THF:H2O = 1:1 (8)
toluene (1) THF:H2O = 1:1 (8)
toluene (1) THF:MeOH = 1:1 (8)
toluene (1) MeOH (4)
toluene (1) THF:MeOH = 1:1 (4)
toluene (1) THF:MeOH = 1:1 (4) 81
[a] Yield of recovered 1Aa
generated 3Aa in 78% and 81% yields, respectively (entries 5, 6).
Thus, entry 6 showed the best result, generating 3Aa in good yield.
As a gram-scale experiment, treatment of ketone 1Aa (4.0 mmol)
under the same procedure and conditions as those of entry 6 gave
Scheme 1. Construction of Phenanthridine Core
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10.1002/ejoc.201901278
European Journal of Organic Chemistry
Scheme 2. Transformation of Aryl Biaryl Ketones 1 to 6-Aryl-
phenanthridines 3.
[a] Substrate 1Aa (4.0 mmol) was used.
[b] Yield of recoverd ketone 1Ad. Reaction temperature at 1st step reaction
was 110 °C.
[c] Reaction temperature at 1st step reaction was 110 °C.
[d] Reaction time at 2nd step reaction was 4 h.
[e] Toluene (4.0 mL) was used as a solvent at 1st step reaction.
[f] Toluene (2.0 mL) was used as a solvent at 1st step reaction.
3-methyl-6-phenylphenanthridine 3Aa in 83% yield, as shown in
Scheme 2.
Based on those results, aryl o-(p-methylphenyl)phenyl ketones
1A and aryl o-biphenyl ketones 1B, bearing phenyl (a), p-
methylphenyl (b), m-methylphenyl (c), o-methylphenyl (d), p-
methoxyphenyl (e), p-fluorophenyl (f), p-chlorophenyl (g), p-
bromophenyl (h), 2-naphthyl (i), benzothiophen-2-yl (j), and
benzofuran-2-yl (k) groups, were treated with 1,1,1,3,3,3-
hexamethyldisilazane (2.0 equiv.) in the presence of Sc(OTf)3 (0.2
equiv.) in toluene (1 mL) at 90 °C for 15 h (1st step), followed by
removal of the solvent and the subsequent reaction with molecular
iodine (1.5 equiv.) and K2CO3 (3.0 equiv.) at 60 °C for 2 h (2nd
step) to give 3-methyl-6-arylphenanthridines 3Ab~3Ak, and 6-
arylphenanthridines 3Ba, 3Bb, and 3Be~3Bk in good yields,
except 3Ad in moderate yield, as shown in Scheme 2. Aryl o-(p-
methoxyphenyl)phenyl
ketones
1C
and
aryl
o-(p-
chlorophenyl)phenyl ketones 1D bearing phenyl (a), p-
methylphenyl (b), p-methoxyphenyl (e), p-fluorophenyl (f), and p-
chlorophenyl (g), were also treated under the same procedure and
conditions
to
generate
the
corresponding
6-aryl-3-
methoxyphenanthridines 3Ca, 3Cb, and 3Ce~3Cg and 6-aryl-3-
chlorophenanthridines 3Da, 3Db, and 3De~3Dg in good to
moderate yields, as shown in Scheme 2, respectively. When o-(m-
methylphenyl)phenyl phenyl ketone 1Ea was used as the substrate
under the same procedure and conditions, 4-methyl-6-
phenylphenanthridine 3Ea was obtained as a single product in 78%
yield.
Submitted to the European Journal of Organic Chemistry
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10.1002/ejoc.201901278
European Journal of Organic Chemistry
The direct treatment of o-(p-methylphenyl)phenyl phenyl ketone
1Aa (1.0 mmol) with molecular iodine (4.0 mmol) in aq. NH3 (3.0
at room temperature gave the corresponding aryl o-bromophenyl
ketones 1Aa’, 1Ae’, and 1Al’ in 98%, 99%, and 94% yields,
respectively, as shown in Scheme 3. Then, aryl o-bromophenyl
ketones 1Aa’, 1Ae’, and 1Al’ were treated with 4-
methylphenylboronic acid in the presence of PdCl2(Ph3P)2 and
K2CO3 at 70 °C for 18 h to form aryl o-(p-methylphenyl)phenyl
ketones 1Aa, 1Ae, and 1Al in 80%, 78%, and 82% yields,
respectively. The final treatment of aryl o-(p-methylphenyl)phenyl
ketones 1Aa, 1Ae, and 1Al with 1,1,1,3,3,3-hexamethyldisilazane
in the presence of Sc(OTf)3 in toluene at 90 °C for 15 h, followed
by removal of the solvent and the subsequent reaction with
molecular iodine and K2CO3 at 60 °C for 2 h gave 6-aryl-3-methyl-
phenanthridines 3Aa, 3Ae, and 3Al in 81%, 72%, and 82% yields,
respectively.
mL) at 60 °C for 15
h did not generate 3-methyl-6-
phenylphenanthridine 3Aa at all and instead, ketone 1Aa was
recovered quantitatively. Thus, the effective and certain formation
of ketimine 2Aa is important. On the other hand, when ethyl o-(p-
methylphenyl)phenyl
ketone
and
n-butyl
o-(p-
methylphenyl)phenyl ketone were used instead of aryl o-biaryl
ketones under the same procedure and conditions, 6-ethyl-3-
methylphenanthridine and 6-butyl-3-methylphenanthridine were
not obtained at all. This is probably because the formed imines
isomerized into enamines at the 1st reaction step. Moreover,
treatment of o-(p-methylphenyl)benzaldehyde with 1,1,1,3,3,3-
hexamethyldisilazane (2.0 equiv.) in the presence of Sc(OTf)3 (0.2
equiv.) in toluene (1.0 mL) at 90 °C for 15 h (1st step), followed by
removal of the solvent and the subsequent reaction with molecular
iodine (1.5 equiv.) and K2CO3 (3.0 equiv.) at 60 °C for 2 h (2nd
step) gave 3-methylphenanthridine only in 20% yield together with
o-(p-methylphenyl)benzonitrile in 75% yield. Thus, the present
method is not practical for the preparation of 6-unsubstituted
phenanthridines.
Once 6-arylphenanthridines were obtained, they could be
smoothly functionalized.
For example, treatment of 6-(4’-
bromophenyl)-3-methylphenanthridine 3Ah with n-BuLi (1.1
equiv.) in THF at -50 °C for 0.5 h, followed by the reaction with
DMF from -10 °C to room temperature for 1 h, and then with aq.
NH4Cl gave 6-(4’-formylphenyl)-3-methylphenanthridine 4A-1 in
68% yield, as shown in Scheme 4. The reaction of 3Ah with p-
methoxybenzamide in the presence of CuI (0.04 equiv.), K2CO3,
and N,N’-dimethylethylenediamine (DMEDA) in toluene under
refluxing conditions gave N-[4’-(3”-methylphenanthridine-6”-
yl)phenyl]-4-methoxybenzamide 4A-2 in 60% yield. Treatment of
3Ah with PhB(OH)2 (1.2 equiv.) and K2CO3 in the presence of
PdCl2(Ph3P)2 (0.04 equiv.) in a mixture of DMF and water at 70 °C
for 6 h, and with ethynylbenzene (1.5 equiv.) in the presence of
PdCl2(Ph3P)2 (0.04 equiv.) and CuI (0.04 equiv.) in a mixture of
DMF and Et3N at 60 °C for 6 h gave 6-(p-biphenyl)-3-
Scheme 3. Transformation of o-Bromobenzoic Acid to 6- Arylphenant
hridines 3 via Aryl Biaryl Ketones
methylphenanthridine
4A-3
and
3-methyl-6-[(p-
phenylethynyl)phenyl]phenanthridine 4A-4 in 92% and 87% yields,
respectively.
Scheme 4. Derivatization of 6-(4’-Bromophenyl)phenanthridine 3A
h
Reaction conditions:
(a) (COCl)2 (1.3 equiv.), DMF (2 drops), CH2Cl2 (10 mL), r.t., 2 h
(b) evaporation
(c) 1Aa’ : AlCl3 (1.5 equiv.), Benzene (7.5 mL), 0 °C → r.t., 18 h
1Ac’ : AlCl3 (1.3 equiv.), Anisole (1.5 equiv.), CH2Cl2 (10 mL),
0 °C → r.t., 5 h
1Aj’ : AlCl3 (1.5 equiv.), tButylbenzene (2.5 mL), CH2Cl2 (10 mL),
0 °C → r.t., 18 h
(d) 4-Methylphenylboronic Acid (1.2 equiv.), PdCl2(PPh3)2 (0.05 equiv.),
K2CO3 (2.0 equiv.), DMF : H2O = 5 : 1 (60 mL), 70 °C, 18 h
(e) 1) TMS2NH (2.0 equiv.), Sc(OTf)3 (0.2 equiv.), toluene (1 mL), 90 °C,
15 h
2) evaporation
3) I2 (1.5 equiv), K2CO3 (3.0 equiv.), THF : MeOH = 1 : 1 (4 mL),
60 °C, 2 h
One of the advantages of the present method for the preparation
of 6-arylphenanthridines is that the starting materials, aryl o-biaryl
ketones, can be obtained easily from the reaction of o-aroyl
chlorides and arenes in the presence of AlCl3 using the Friedel-
Crafts acylation reaction. Thus, treatment of o-bromobenzoyl
chloride prepared from o-bromobenzoic acid and oxalyl chloride,
with benzene, anisole, and t-butylbenzene in the presence of AlCl3
Submitted to the European Journal of Organic Chemistry
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10.1002/ejoc.201901278
European Journal of Organic Chemistry
doublet; t = triplet; q = quartet; sext = sextet; m = multiplet; br = broad),
coupling constant (Hz), integration, and assignment. 13C NMR spectra
were measured on 100 MHz spectrometers. Chemical shifts were recorded
in ppm from the solvent resonance employed as the internal standard
(CDCl3 at 77.0 ppm, or DMSO-d6 at 39.5 ppm). Characteristic peaks in the
infrared (IR) spectra were recorded in wave number, cm-1 on a JASCO
FT/IR-4100 spectrometer. Melting points were determined using a Yamato
Melting Point Apparatus Model MP-21. High-resolution mass spectra
(HRMS) were recorded by Thermo Fisher Scientific Exactive Orbitrap
A possible reaction pathway is shown in Scheme 5. Treatment of
aryl o-biaryl ketone 1 with 1,1,1,3,3,3-hexamethyldisilazane in the
presence of Sc(OTf)3 generates aryl o-biaryl ketimine 2. Aryl o-
biaryl ketimine 2 reacts with molecular iodine in the presence of
K2CO3 to form N-iodoimine I. Once N-iodoimine I is formed,
smooth N-I bond cleavage of N-iodoimine I occurs to form an
iminyl radical that further cyclizes onto the aromatic ring to
provide 6-arylphenanthridine 3. Practically, when the reactions
with o-(p-methylphenyl)phenyl phenyl ketone 1Aa (1.0 mmol)
were treated in the presence of 2,6-di-t-butyl-p-cresol (BHT, 3.0
equiv.) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy radical
(4-hydroxy-TEMPO, 3.0 equiv.) at 2nd step reaction under the
same procedure and conditions as those of entry 6 in Table 1, yield
of 3-methyl-6-phenylphenanthridine 3Aa was 0% and 12%,
together with ketimine 2Aa in 51% and 78% yields, respectively.
mass spectrometers.
Melting points were uncorrected. Thin-layer
chromatography (TLC) was performed using 0.25 mm silica gel plates
(60F254). The products were purified by column chromatography on
neutral silica gel 60N (63-200 mesh).
Typical Procedure for Preparation of Aryl o-Biaryl Ketones (1); for
1Aa, 1Ac, 1Ad, 1Ba, 1Ca, and 1Da: PhLi (1.12 M solution in cyclohexane
and diethyl ether, 8.93 mL, 10 mmol) was added dropwise to a solution of
2-cyano-4'-methylbiphenyl (1.16 g, 6.0 mmol) in THF (20.0 mL) at −10 °C
under Ar atomosphere. After 1 h, the reaction mixture was quenched with
aq. HCl (4M, 30.0 mL) and extracted with AcOEt (3 × 80.0 mL). The
organic layer was dried over Na2SO4. After filtration and removal of the
solvent under reduced pressure, the residue was purified by column
chromatography on silica gel (hexane : EtOAc = 8 : 1) to give o-(p-
methylphenyl)phenyl phenyl ketone 1Aa (998.0 mg, 60%).
Scheme 5. Possible Reaction Pathway
Typical Procedure for Preparation of Aryl o-Biaryl Ketones (2); for
1Af, 1Ag, 1Ah, 1Ai, 1Aj, 1Ak, 1Bf, 1Bg, 1Bi, 1Bj, and 1Bk: (1) o-(p-
Methylphenyl)benzoic acid (3.184 g, 15 mmol) was dissolved in dry THF
(72.0 mL) under Ar atmosphere. LiAlH4 (1.42 g, 37.5 mmol) was slowly
added to the solution at 0 °C and then, the mixture was stirred at room
temperature for 4 h. The reaction mixture was quenched with aq. NaOH
solution (2 M, 30.0 mL). The reaction mixture was poured into water (60
mL) and the obtained mixture was filtered. The filtrates were extracted
with AcOEt (3 × 60.0 mL). The organic layer was dried over Na2SO4.
After filtration, the solvent was removed to give o-(p-
methylphenyl)benzylalcohol as colorless oil.
(2) MnO2 (13.04g, 150 mmol) was added to
a
solution of o-(p-
methylphenyl)benzylalcohol in CH2Cl2 (50.0 mL).
The resulting
suspension was warmed under refluxing conditions overnight. Then, the
mixture was filtered through a celite pad and the filtrates were concentrated
in vacuo. Purification of the residue by short column chromatography on
silica gel (hexane:AcOEt = 10:1) yielded o-(p-methylphenyl)benzaldehyde
(2.06 g, 70%).
(3) n-BuLi (1.55 M solution in hexane, 2.13 mL, 3.3 mmol) was added
dropwise to a solution of benzo[b]thiophene (0.40 g, 3.0 mmol) in THF (3.0
mL) at −50 °C under Ar atomosphere.
After
1
h., o-(p-
methylphenyl)benzaldehyde (0.61 g, 3.1 mmol) in THF (3.0 mL) was
added to the mixture. The obtained mixture was gradually warmed to room
temperature and stirred for 3 h. Then, the reaction mixture was quenched
with sat. aq. NH4Cl. The reaction mixture was extracted with AcOEt (3 ×
60.0 mL). The organic layer was washed with brine, dried over Na2SO4,
and filtered.
(benzo[b]thiophene-2-yl)--[o-(p-methylphenyl)phenyl]methanol.
(4) MnO2 (2.61 g, 30 mmol) was added to solution of -
(benzo[b]thiophene-2-yl)--[o-(p-methylphenyl)phenyl]methanol in
Removal of the solvent by evaporation gave -
a
CH2Cl2 (30.0 mL). The resulting suspension was warmed under refluxing
conditions overnight. Then, the mixture was filtered through celite pad and
the filtrates were concentrated in vacuo. Purification of the residue by short
column chromatography on silica gel (hexane:AcOEt = 10:1) yielded
benzo[b]thiophen-2-yl o-(p-methylphenyl)phenyl ketone 1Aj (610.8 mg,
62%).
Typical Procedure for Preparation of Aryl o-Biphenyl Ketones (3); for
1Ab, 1Ae, 1Bb, 1Be, and 1Cb: (1) To biphenyl-2-carboxylic acid (793.0
mg, 4.0 mmol) in CH2Cl2 (10.0 mL) in a 100 mL round-bottom flask was
added oxalyl chloride (0.45 mL, 5.2 mmol). Then, DMF (one drop) was
added to the mixture and the obtained mixture was stirred at room
temperature for 5 h. The resulting mixture was concentrated under reduced
pressure to afford o-phenylbenzoyl chloride quantitatively.
(2) To a solution of o-phenylbenzoyl chloride in CH2Cl2 (10.0 mL) was
added anisole (125.4 μL, 6.0 mmol) at 0 °C. The mixture was stirred for a
few min. Then, anhydrous AlCl3 (693.9 mg, 5.2 mmol) was added and the
obtained mixture was stirred for 24 h at room temperature. Then, the
reaction mixture was quenched with iced water (~1 g) and extracted with
CHCl3 (3 × 60.0 mL). The organic layer was dried over Na2SO4. After
filtration and removal of the solvent under reduced pressure, the residue
was purified by flash column chromatography on neutral silica gel
(hexane : AcOEt = 8 : 1) to afford o-biphenyl p-methoxyphenyl ketone 1Be
(818.9 mg, 71%).
Conclusions
Treatment of aryl o-biaryl ketones with 1,1,1,3,3,3-
hexamethyldisilazane in the presence of Sc(OTf)3 in toluene,
followed by removal of the solvent and the subsequent reaction
with molecular iodine and K2CO3 gave 6-arylphenanthridines in
one pot in good to moderate yields. The key points of the present
reactions are the formation of aryl o-biaryl ketimines, their N-iodo
imines, and imino-nitrogen-centered radicals, and their cyclization
onto the o-aryl groups in the presence of molecular iodine.
Because aryl o-biaryl ketones can be obtained from the Friedel-
Crafts acylation reaction of arenes with o-arylbenzoyl chlorides,
we believe that the present method would be useful for the
preparation of 6-arylphenanthridines.
Experimental Section
General. 1H NMR spectra were measured on 400 MHz spectrometers.
Chemical shifts were recorded as follows: chemical shift in ppm from
internal tetramethylsilane on the δ scale, multiplicity (s = singlet; d =
Typical Procedure for Preparation of Aryl o-Biphenyl Ketones 1Cb,
1Ce, 1Cf, 1Cg, 1Db, 1De, 1Df, 1Dg, and 1Ea:
Submitted to the European Journal of Organic Chemistry
5
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201901278
European Journal of Organic Chemistry
(1) To a 200 mL round-bottom flask were added 2-iodobenzoic acid (25.0 g,
100.0 mmol), CH2Cl2 (50.0 mL), and oxalyl chloride (9.12 mL, 105 mmol).
The mixture was stirred at room temperature for 5 min. Then, DMF (2
drops) was added, and the mixture was stirred at room temperature for 5 h.
The resulting mixture was concentrated under reduced pressure to afford 2-
iodobenzoyl chloride quantitatively. To a solution of 2-iodobenzoyl
chloride in THF (40.0 mL) was added aq.NH3 (10.0 mL) at r.t., and the
mixture was stirred for 2 h. Then, the reaction mixture was quenched with
aq. NaHCO3 (100.0 mL) and filtered to give 2-Iodobenzamide (19.8 g,
80%).
(2) To a 200 mL round-bottom flask were added 2-iodobenzamide (19.8 g,
80.0 mmol) and P2O5 (12.0 g, 80.0 mmol). The mixture was stirred at
160 °C for 3 h. Then, the reaction mixture was quenched with water (100.0
mL) and extracted with CHCl3 (3 × 80.0 mL). The organic layer was dried
over Na2SO4. After filtration and removal of the solvent under reduced
pressure, the residue was purified by flash column chromatography on
neutral silica gel (hexane : AcOEt = 8 : 1) to afford 2-Iodobenzonitrile
(14.3 g, 78%).
o-(p-Methylphenyl)phenyl p-Methylphenyl Ketone (1Ab)11,12
: white
solid; Mp: 148-152 °C; IR (neat) 1659, 1256, 925, 766, 605 cm-1; 1H-NMR
(400 MHz, CDCl3): δ = 2.23 (s, 3H), 2.34 (s, 3H), 7.02 (d, 2H, J = 7.7 Hz),
7.11 (d, 2H, J = 7.7 Hz), 7.17 (d, 2H, J = 8.2 Hz), 7.39-7.48 (m, 3H), 7.52-
7.56 (m, 1H), 7.60 (d, 2H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ
= 21.1, 21.6, 126.6, 128.5, 128.7 (2C), 128.9 (2C), 129.0, 130.0 (2C), 130.1,
130.2 (2C), 134.8, 137.0, 137.3, 139.1, 141.0, 143.7, 198.4; HRMS (ESI)
Calcd for C21H19O [M+H]+ = 287.1430, Found = 287.1426.
m-Methylphenyl o-(p-methylphenyl)phenyl Ketone (1Ac): white solid;
Mp: 142-146 °C; IR (neat) 1662, 1280, 821, 757 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 2.26 (s, 3H), 2.30 (s, 3H), 7.02 (d, 2H, J = 8.1 Hz), 7.15 (d, 2H,
J = 8.1 Hz), 7.19 (d, 1H, J = 7.4 Hz), 7.25 (d, 1H, J = 7.4 Hz), 7.40-7.57 (m,
6H); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.0, 21.1, 126.6, 127.3, 127.9,
128.6, 128.7 (2C), 128.9 (2C), 130.0, 130.1, 130.3, 133.6, 136.9, 137.2,
137.3, 137.7, 138.9, 141.1, 198.8; HRMS (ESI) Calcd for C21H19O [M+H]+
= 287.1430, Found = 287.1426.
o-Methylphenyl o-(p-methylphenyl)phenyl Ketone (1Ad): white solid;
1
Mp: 140-145 °C; IR (neat) 1660, 1268, 926, 757, 734 cm-1; H-NMR (400
(3) To a mixture of 2-iodobenzonitrile (2.29 g, 10.0 mmol) and 4-
methoxyphenylboronic acid (1.83 g, 12.0 mmol) in DMF (100.0 mL) was
added PdCl2(PPh3)2 (351.0 mg, 0.5 mmol) under the argon atmosphere.
The obtained mixture was stirred for 30 min at room temperature. Then,
K2CO3 (2.76 g, 20.0 mmol) in H2O (20.0 mL) was added to the mixture,
and the obtained mixture was stirred for 18 h at 70 °C. Water (100.0 mL)
was added to the reaction mixture, and the product was extracted with
hexane : AcOEt = 4 : 1 (70.0 mL × 3). The organic layer was washed with
brine and dried over Na2SO4. After filtration and removal of the solvent
under reduced pressure, the residue was purified by column
chromatography (hexane : EtOAc = 8 : 1) on neutral silica gel to give o-(p-
methoxyphenyl)benzonitrile (1.51 g, 72%).
(4) n-BuLi (1.55 M solution in hexane, 2.13 mL, 3.3 mmol) was added
dropwise to a solution of 1-bromo-4-chlorobenzene (574.4 mg, 3.0 mmol)
in THF (3.0 mL) at −50 °C under Ar atomosphere. After 1 h, o-(p-
methoxyphenyl)benzonitrile (648.7 mg, 3.1 mmol) in THF (3.0 mL) was
added, and the obtained mixture was gradually warmed to r.t., and then the
reaction mixture was stirred for 0.5 h. Then, the reaction mixture was
quenched with 4M HCl (30.0 mL) and extracted with AcOEt (3 × 40.0 mL).
The organic layer was dried over Na2SO4. After filtration and removal of
the solvent under reduced pressure, the residue was purified by column
chromatography (hexane : EtOAc = 8 : 1) on neutral silica gel to give p-
chlorophenyl o-(p-methoxyphenyl)phenyl ketone 1Cg (697.2 mg, 72%).
Typical Procedure for Preparation of Ary Biaryl Ketones 1 with the
Friedel-Crafts Acylation (Scheme 3): (1) To a mixture of o-bromobenzoic
acid (1.0 g, 5.0 mmol) in CH2Cl2 (10.0 mL) was added oxalyl chloride
(0.58 mL, 6.5 mmol). The mixture was stirred at room temperature for 5
min. Then, DMF (2 drops) was added to the mixture and the obtained
mixture was stirred at room temperature for 2 h. The resulting mixture was
evaporated under reduced pressure to afford o-bromobenzoyl chloride
quantitatively.
MHz, CDCl3): δ = 2.25 (s, 3H), 2.43 (s, 3H), 6.98-7.02 (m, 3H), 7.06-7.11
(m, 3H), 7.18-7.23 (m, 2H), 7.39-7.44 (m, 2H) , 7.52-7.56 (m, 2H);
13C{1H}NMR (100 MHz, CDCl3): δ = 20.8, 20.9, 124.8, 126.7, 128.5 (2C),
128.6 (2C), 129.3, 130.1, 130.5, 130.9, 131.1, 131.2, 136.7, 137.5, 137.7,
139.0, 140.1, 141.6, 200.4; HRMS (ESI) Calcd for C21H19O [M+H]+
287.1430, Found = 287.1428.
=
p-Methoxyphenyl o-(p-Methylphenyl)phenyl Ketone (1Ae): white solid;
1
Mp: 130-133 °C; IR (neat) 1658, 1259, 924, 766, 608 cm-1; H-NMR (400
MHz, CDCl3): δ = 2.25 (s, 3H), 3.80 (s, 3H), 6.77 (d, 2H, J = 7.5 Hz), 7.02
(d, 2H, J = 7.5 Hz), 7.17 (d, 2H, J = 8.4 Hz), 7.40-7.47 (m, 3H), 7.51-7.55
(m, 1H), 7.67 (d, 2H, J = 8.4 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =
21.1, 55.4, 113.4 (2C), 126.7, 128.4, 128.7 (2C), 129.0 (2C), 129.9, 130.0,
130.4, 132.4 (2C), 136.9, 137.3, 139.2, 140.7, 163.3, 197.4; HRMS (ESI)
Calcd for C21H19O2 [M+H]+ = 303.1379, Found = 303.1376.
p-Fluorophenyl o-(p-Methylphenyl)phenyl Ketone (1Af): white solid;
Mp: 75-78 °C; IR (neat) 1664, 1259, 924, 768, 603 cm-1; 1H-NMR (400
MHz, CDCl3): δ = 2.25 (s, 3H), 6.94 (d, 2H, J = 8.2 Hz), 7.01 (d, 2H, J =
8.0 Hz), 7.13 (d, 2H, J = 8.2 Hz), 7.42-7.49 (m, 3H), 7.55-7.59 (m, 1H),
7.64-7.69 (m, 2H); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.0, 115.2 (d, JC-
F = 21.2 Hz, 2C), 126.9, 128.6, 128.8 (2C), 129.0 (2C), 130.0, 130.4, 132.5
(d, JC-F = 8.4 Hz, 2C), 133.7 (d, JC-F = 3.6 Hz), 137.1, 137.2, 138.5, 140.9,
165.4 (d, JC-F = 242.1 Hz), 197.4; HRMS (ESI) Calcd for C20H16FO
[M+H]+ = 291.1179, Found = 291.1179.
p-Chlorophenyl o-(p-Methylphenyl)phenyl Ketone (1Ag): white solid;
1
Mp: 121-122 °C; IR (neat) 1661, 1258, 923, 767, 653 cm-1; H-NMR (400
MHz, CDCl3): δ = 2.26 (s, 3H), 7.02 (d, 2H, J = 7.8 Hz), 7.13 (d, 2H, J =
7.8 Hz), 7.24 (d, 2H, J = 8.8 Hz), 7.42-7.48 (m, 3H), 7.55-7.60 (m, 3H);
13C{1H}NMR (100 MHz, CDCl3): δ = 21.1, 126.9, 128.4 (2C), 128.6, 128.8
(2C), 129.1 (2C), 130.1, 130.5, 131.2 (2C), 135.7, 137.0, 137.3, 138.3,
139.1, 141.0, 197.7; HRMS (ESI) Calcd for C20H16ClO [M+H]+ = 307.0883,
Found = 307.0882.
A solution of o-bromobenzoyl chloride in benzene (7.5 mL) was stirred for
a few min at 0 °C. Anhydrous AlCl3 (1.00 g, 7.5 mmol) was added to the
mixture and the obtained mixture was stirred for 24 h at room temperature.
The reaction mixture was quenched with iced water (~1 g) and extracted
with CHCl3 (3 × 40.0 mL). The organic layer was dried over Na2SO4.
After filtration and removal of the solvent under reduced pressure, the
residue was purified by flash column chromatography on neutral silica gel
(hexane : AcOEt = 8 : 1) to afford o-bromophenyl phenyl ketone 1Aa’
(1.28 g, 98%).
p-Bromophenyl o-(p-Methylphenyl)phenyl Ketone (1Ah): white solid;
1
Mp: 125-127 °C; IR (neat) 1661, 1258, 923, 767, 653 cm-1; H-NMR (400
MHz, CDCl3): δ = 2.26 (s, 3H), 7.01 (d, 2H, J = 7.6 Hz), 7.12 (d, 2H, J =
7.6 Hz), 7.39-7.59 (m, 8H); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.1,
126.9, 128.0, 128.6, 128.8 (2C), 129.1 (2C), 130.1, 130.5, 131.3 (2C),
131.4 (2C), 136.1, 137.0, 137.3, 138.3, 141.0, 197.9; HRMS (ESI) Calcd
for C20H1679BrO [M+H]+ = 351.0379 Found = 351.0379.
o-(p-Methylphenyl)phenyl -Naphthyl Ketone((1Ai): yellow solid; Mp:
1
95-97 °C; IR (neat) 1657, 1288, 920, 756, 666 cm-1; H-NMR (400 MHz,
(2) To a mixture of o-bromophenyl phenyl ketone 1Aa’ (1.28 g, 4.9 mmol)
and p-methylphenylboronic acid (0.82 g, 6.0 mmol) in DMF (50.0 mL) was
added PdCl2(PPh3)2 (0.18 g, 0.25 mmol) under argon atmosphere. The
obtained mixture was stirred for 30 min at room temperature. Then, K2CO3
(1.38 g, 10.0 mmol) in H2O (10.0 mL) was added to the mixture, and the
obtained mixture was stirred at 70 °C for 18 h. Water (50.0 mL) was added
to the reaction mixture, and the product was extracted with a mixture of
hexane and AcOEt ( 4 : 1, 50.0 mL × 3). The organic layer was washed
with brine and dried over Na2SO4. After filtration and removal of the
solvent under reduced pressure, the residue was purified by column
chromatography (hexane : EtOAc = 8 : 1) on silica gel to give o-(p-
methylphenyl)phenyl phenyl ketone 1Aa (1.10 g, 80%).
CDCl3): δ = 2.18 (s, 3H), 6.70 (d, 2H, J = 8.1 Hz), 7.19 (d, 2H, J = 8.1 Hz),
7.44-7.65 (m, 6H), 7.76-7.82 (m, 3H), 7.87 (d, 1H, J = 8.6 Hz), 8.11 (s,
1H); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.0, 125.0, 126.5, 126.7, 126.7,
127.6, 128.1, 128.4, 128.4, 128.7 (2C), 129.0 (2C), 129.5, 130.2, 132.2,
132.5, 134.7, 135.4, 137.0, 137.3, 139.0, 141.2, 198.7; HRMS (ESI) Calcd
for C24H19O [M+H]+ = 323.1430, Found = 323.1427.
Benzo[b]thiophen-2-yl o-(p-Methylphenyl)phenyl Ketone (1Aj): orange
solid; Mp: 132-135 °C; IR (neat) 1650, 1262, 911, 740, 666 cm-1; 1H-NMR
(400 MHz, CDCl3): δ = 2.24 (s, 3H), 7.06 (d, 2H, J = 7.6 Hz), 7.24 (d, 2H,
J = 7.6 Hz), 7.34 (t, 1H, J = 8.2 Hz), 7.40-7.48 (m, 2H), 7.50-7.53 (m, 2H),
7.56-7.62 (m, 2H), 7.74 (d, 1H, J = 8.2 Hz), 7.82 (d, 1H, J = 8.2 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 21.0, 122.8, 124.8, 125.9, 126.7,
127.3, 128.3, 128.6 (2C), 129.2 (2C), 130.3, 130.5, 132.7, 137.0, 137.1,
138.2, 138.8, 140.7, 142.9, 144.2, 192.2; HRMS (ESI) Calcd for C22H17OS
[M+H]+ = 329.0994, Found = 329.0991.
o-(p-Methylphenyl)phenyl Phenyl Ketone (1Aa)10: white solid; Mp: 82-
85 °C; IR (neat) 1659, 1256, 925, 767, 666 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 2.23 (s, 3H), 7.00 (d, 2H, J = 8.0 Hz), 7.14 (d, 2H, J = 7.4 Hz),
7.25-7.28 (m, 2H), 7.38-7.48 (m, 4H), 7.52-7.55 (m, 1H), 7.65 (d, 2H, J =
7.4 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.1, 126.8, 128.1, 128.8
(2C), 128.9 (2C), 129.0, 130.0 (2C), 130.1 (2C), 130.5, 132.8, 137.1, 137.3,
Benzofuran-2-yl o-(p-Methylphenyl)phenyl Ketone (1Ak): white solid;
Mp: 117-119 °C; IR (neat) 1650, 971, 750 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 2.23 (s, 3H), 7.04 (d, 2H, J = 7.6 Hz), 7.12 (s, 1H), 7.22-7.27
(m, 3H), 7.40-7.54 (m, 4H), 7.56-7.64 (m, 3H); 13C{1H}NMR (100 MHz,
CDCl3): δ = 21.1, 112.5, 116.8, 123.3, 123.8, 126.9, 127.0, 128.3, 128.7,
128.8 (2C), 129.2, 130.4, 130.9, 137.1, 137.3, 137.8, 141.3, 152.7, 156.0,
137.4, 138.9, 141.2, 198.9; HRMS (ESI) Calcd for C20H17O [M+H]+
273.1273, Found = 273.1276.
=
Submitted to the European Journal of Organic Chemistry
6
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201901278
European Journal of Organic Chemistry
187.6; HRMS (ESI) Calcd for C22H17O2 [M+H]+ = 313.1222, Found =
313.1221.
p-Methylphenyl o-(p-Methoxyphenyl)phenyl Ketone (1Cb): white solid;
Mp: 100-102 °C; IR (neat) 1656, 1252, 832, 741 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 2.34 (s, 3H), 3.73 (s, 3H), 6.75 (d, 2H, J = 8.8 Hz), 7.09 (d, 2H,
J = 8.2 Hz), 7.20 (d, 2H, J = 8.8 Hz), 7.39-7.46 (m, 3H), 7.50-7.56 (m, 1H),
7.58 (d, 2H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.7, 55.2,
113.7 (2C), 126.5, 128.5, 128.9 (2C), 129.9, 130.0 (2C), 130.1 (2C), 132.7,
132.7, 134.8, 139.0, 140.5, 143.7, 158.9, 198.6; HRMS (ESI) Calcd for
C21H19O2 [M+H]+ = 303.1379, Found = 303.1378.
p-(tert-Butyl)phenyl o-(p-Methylphenyl)phenyl Ketone (1Al): white
solid; Mp: 118-120 °C; IR (neat) 1664, 1251, 927, 765 cm-1; 1H-NMR (400
MHz, CDCl3): δ = 1.29 (s, 9H), 2.25 (s, 3H), 7.02 (d, 2H, J = 7.7 Hz), 7.16
(d, 2H, J = 8.2 Hz), 7.32 (d, 2H, J = 8.6 Hz), 7.39-7.48 (m, 3H), 7.54 (t, 1H,
J = 7.7 Hz), 7.64 (d, 2H, J = 8.6 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =
20.9, 30.9 (3C), 35.0, 124.9 (2C), 126.4, 128.5, 128.7 (2C), 128.8 (2C),
129.9 (2C), 130.0, 130.0, 134.7, 136.7, 137.3, 138.9, 141.1, 156.3, 198.1;
HRMS (ESI) Calcd for C24H25O [M+H]+ = 329.1900, Found = 329.1901.
o-Biphenyl Phenyl Ketone (1Ba)11: white solid; Mp: 85-86 °C; IR (neat)
1661, 1260, 927, 696 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 7.13-7.22 (m,
3H), 7.24-7.29 (m, 4H), 7.38-7.53 (m, 4H), 7.56-7.60 (m, 1H), 7.63-7.65
(m, 2H) ; 13C{1H}NMR (100 MHz, CDCl3): δ = 127.0, 127.3, 128.0 (2C),
128.2 (2C), 128.7, 129.0 (2C), 129.9 (2C), 130.0, 130.3, 132.8, 137.3,
o-(p-Methoxyphenyl)phenyl p-Methoxyphenyl Ketone (1Ce): white
1
solid; Mp: 95-99 °C; IR (neat) 1655, 1250, 1147, 761, 604 cm-1; H-NMR
(400 MHz, CDCl3): δ = 3.74 (s, 3H), 3.81 (s, 3H) , 6.74-6.79 (m, 4H), 7.21
(d, 2H, J = 8.7 Hz) , 7.39-7.46 (m, 3H), 7.53 (t, 1H, J = 8.0 Hz), 7.66 (d, 2H,
J = 8.7 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 55.1, 55.4, 113.4 (2C),
113.7 (2C), 126.5, 128.4, 129.9, 129.9, 130.0 (2C), 130.3, 132.3 (2C),
132.7, 139.1, 140.3, 158.9, 163.3, 197.6; HRMS (ESI) Calcd for C21H19O3
[M+H]+ = 319.1328, Found = 319.1326.
138.9, 140.1, 141.1, 198.9; HRMS (ESI) Calcd for C19H15O [M+H]+
259.1117, Found = 259.1115.
=
p-Fluorophenyl o-(p-Methoxyphenyl)phenyl Ketone (1Cf): yellow oil;
1
o-Biphenyl p-Methylphenyl Ketone (1Bb): white solid; Mp: 120-122 °C;
IR (neat) 1656, 1254, 925, 746 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.33
(s, 3H), 7.08 (d, 2H, J = 7.8 Hz), 7.15-7.30 (m, 5H), 7.42-7.49 (m, 3H),
7.52-7.58 (m, 3H); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.6, 126.9,
127.2, 128.2 (2C), 128.6, 128.8 (2C), 128.9 (2C), 130.0, 130.1, 130.1 (2C),
134.8, 139.2, 140.2, 140.9, 143.7, 198.3; HRMS (ESI) Calcd for C20H17O
[M+H]+ = 273.1273, Found = 273.1273.
IR (neat) 1663, 1596, 1238, 768, 603 cm-1; H-NMR (400 MHz, CDCl3): δ
= 3.73 (s, 3H), 6.74 (d, 2H, J = 8.8 Hz), 6.93 (t, 2H, J = 7.8 Hz), 7.16 (d,
2H, J = 8.8 Hz), 7.41-7.49 (m, 3H), 7.54-7.59 (m, 1H), 7.62-7.67 (m, 2H);
13C{1H}NMR (100 MHz, CDCl3): δ = 54.9, 113.7 (2C), 115.1 (d, JC-F
21.6 Hz, 2C), 126.6, 128.4, 129.8, 129.9 (2C), 130.3, 132.3, 132.3 (d, JC-F
7.8 Hz, 2C), 133.6 (d, JC-F = 3.8 Hz), 138.4, 140.3, 158.9, 165.2 (d, JC-F
=
=
=
251.1 Hz), 197.3; HRMS (ESI) Calcd for C20H16FO2 [M+H]+ = 307.1128,
Found = 307.1129.
o-Biphenyl p-Methoxyphenyl Ketone (1Be)12: white solid; Mp: 120-
122 °C; IR (neat) 1650, 1260, 1147, 745 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 3.80 (s, 3H), 6.77 (d, 2H, J = 8.8 Hz), 7.15-7.24 (m, 3H), 7.27-
7.30 (m, 2H), 7.42-7.49 (m, 3H), 7.52-7.58 (m, 1H), 7.65 (d, 2H, J = 8.8
Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =55.4, 113.3 (2C), 127.0, 127.3,
128.2 (2C), 128.4, 128.9 (2C), 130.0, 130.0, 130.3, 132.3 (2C), 139.9,
p-Chlorophenyl o-(p-Methoxyphenyl)phenyl Ketone (1Cg): yellow
1
solid; Mp: 78-80 °C; IR (neat) 1661, 1516, 1247, 927, 741 cm-1; H-NMR
(400 MHz, CDCl3): δ = 3.74 (s, 3H), 6.74 (d, 2H, J = 8.8 Hz), 7.16 (d, 2H,
J = 8.6 Hz), 7.23 (d, 2H, J = 8.6 Hz), 7.41-7.49 (m, 3H), 7.54-7.59 (m, 3H);
13C{1H}NMR (100 MHz, CDCl3): δ = 55.1, 113.8 (2C), 126.8, 128.4 (2C),
128.6, 129.9, 130.0 (2C), 130.5, 131.1 (2C), 132.4, 135.6, 138.3, 139.1,
140.2, 140.7, 163.3, 197.3; HRMS (ESI) Calcd for C20H17O2 [M+H]+
289.1223, Found = 289.1220.
=
140.5, 159.0, 197.8; HRMS (ESI) Calcd for C20H16ClO2 [M+H]+
323.0833, Found = 323.0829.
=
o-Biphenyl p-Fluorophenyl Ketone (1Bf): white solid; Mp: 68-70 °C; IR
(neat) 1662, 1147, 930, 743 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 6.91 (t,
2H, J = 8.6 Hz), 7.14-7.26 (m, 5H), 7.45-7.54 (m, 3H), 7.57-7.67 (m, 3H);
13C{1H}NMR (100 MHz, CDCl3): δ = 115.2 (d, JC-F = 21.6 Hz, 2C), 127.2,
127.4, 128.3 (2C), 128.7, 128.9 (2C), 130.0, 130.5, 132.4 (d, JC-F = 8.6 Hz,
2C), 133.7 (d, JC-F = 3.8 Hz), 138.6, 140.0, 140.9, 165.4 (d, JC-F = 242.8 Hz),
197.3; HRMS (ESI) Calcd for C19H14FO [M+H]+ = 277.1022, Found =
277.1020.
o-(p-Chlorophenyl)phenyl Phenyl Ketone (1Da): yellow oil; IR (neat)
1662, 1282, 759, 699 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 7.17-7.20 (m,
4H), 7.31 (t, 2H, J = 7.7 Hz), 7.44-7.52 (m, 4H), 7.58 (t, 1H, J = 7.7 Hz),
7.65 (d, 2H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 127.3,
128.2 (2C), 128.4 (2C), 128.8, 129.9 (2C), 130.0, 130.2 (2C), 130.4, 133.1,
133.5, 137.2, 138.6, 138.8, 139.9, 198.4; HRMS (ESI) Calcd for C19H14ClO
[M+H]+ = 293.0728, Found = 293.0725.
o-Biphenyl p-Chlorophenyl Ketone (1Bg): white solid; Mp: 115-118 °C;
o-(p-Chlorophenyl)phenyl p-Methylphenyl Ketone (1Db): white solid;
1
1
IR (neat) 1660, 1259, 1087, 928, 740 cm-1; H-NMR (400 MHz, CDCl3): δ
Mp: 136-140 °C; IR (neat) 1657, 1258, 831, 768, 681 cm-1; H-NMR (400
= 7.15-7.26 (m, 7H), 7.45-7.53 (m, 3H), 7.55 (d, 2H, J = 8.6 Hz), 7.56-7.62
(m, 1H); 13C{1H}NMR (100 MHz, CDCl3): δ = 127.2, 127.5, 128.3 (2C),
128.4 (2C), 128.7, 128.9 (2C), 130.0, 130.6, 131.1 (2C), 135.7, 138.5,
MHz, CDCl3): δ = 2.35 (s, 3H), 7.12 (d, 2H, J = 7.9 Hz), 7.17-7.21 (m, 4H),
7.42-7.48 (m, 3H), 7.52-7.59 (m, 3H); 13C{1H}NMR (100 MHz, CDCl3): δ
= 21.7, 127.3, 128.4 (2C), 128.7, 129.0 (2C), 130.0, 130.1, 130.1 (2C),
130.2, 133.4, 134.6, 138.7, 139.1, 139.7, 144.1, 198.0; HRMS (ESI) Calcd
for C20H16ClO [M+H]+ = 307.0884, Found = 307.0885.
139.1, 139.9, 141.0, 197.6; HRMS (ESI) Calcd for C19H14ClO [M+H]+
293.0727, Found = 293.0729.
=
o-(p-Chlorophenyl)phenyl p-Methoxylphenyl Ketone (1De): yellow oil;
IR (neat) 1655, 1254, 1147, 759 cm-1; 1H-NMR (400 MHz, CDCl3): δ =
3.83 (s, 3H), 6.80 (d, 2H, J = 8.8 Hz), 7.18-7.23 (m, 4H), 7.42-7.48 (m, 3H),
7.52-7.58 (m, 1H) , 7.65 (d, 2H, J = 8.8 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 55.4, 113.5 (2C), 127.3, 128.4 (2C), 128.5, 129.9, 130.1, 130.1,
130.1 (2C), 132.3 (2C), 133.4. 138.7, 139.2, 139.5, 163.5, 197.0; HRMS
(ESI) Calcd for C20H16ClO [M+H]+ = 307.0884, Found = 307.0885.
o-(p-Chlorophenyl)phenyl p-Fluorophenyl Ketone (1Df): white solid;
o-Biphenyl -Naphthyl Ketone (1Bi): white solid; Mp: 108-110 °C; IR
1
(neat) 1652, 1294, 916, 749, 701 cm-1; H-NMR (400 MHz, CDCl3): δ =
7.08 (t, 1H, J = 7.5 Hz), 7.14 (d, 1H, J = 7.5 Hz), 7.16 (d, 1H, J = 7.5 Hz),
7.30 (d, 2H, J = 7.5 Hz), 7.46-7.65 (m, 6H), 7.74-7.86 (m, 4H), 8.07 (s,
1H); 13C{1H}NMR (100 MHz, CDCl3): δ = 124.9, 126.5, 127.0, 127.3,
127.6, 128.1, 128.2 (2C), 128.4, 128.8, 128.8 (2C), 129.5, 130.1, 130.3,
132.1, 132.5, 134.7, 135.3, 139.0, 140.2, 141.2, 198.6; HRMS (ESI) Calcd
for C23H17O [M+H]+ = 309.1273, Found = 309.1272.
Benzo[b]thiophen-2-yl o-Biphenyl Ketone (1Bj): yellow solid; Mp: 153-
155 °C; IR (neat) 1643, 1291, 755, 700 cm-1; 1H-NMR (400 MHz, CDCl3):
δ = 7.18 (t, 1H, J = 7.3 Hz), 7.23-7.26 (m, 2H), 7.32-7.37 (m, 3H), 7.42 (t,
1H, J = 7.3 Hz), 7.47-7.55 (m, 3H), 7.59-7.63 (m, 2H), 7.72 (d, 1H, J = 8.2
Hz), 7.81 (d, 1H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 122.9,
124.8, 126.0, 127.0, 127.4, 127.5, 128.4, 128.4 (2C), 128.8 (2C), 130.4,
130.6, 132.8, 138.4, 138.8, 140.0, 140.9, 142.9, 144.1, 192.1; HRMS (ESI)
Calcd for C21H15OS [M+H]+ = 315.0837, Found = 315.0835.
Benzofuran-2-yl o-Biphenyl Ketone (1Bk): yellow solid; Mp: 129-
131 °C; IR (neat) 1651, 973, 897, 746 cm-1; 1H-NMR (400 MHz, CDCl3): δ
= 7.12 (s, 1H), 7.15 (t, 1H, J = 7.2 Hz), 7.22-7.26 (m, 3H), 7.36 (d, 2H, J =
7.2 Hz), 7.41 (t, 1H, J = 7.2 Hz), 7.47-7.53 (m, 2H), 7.55 (t, 2H, J = 8.0 Hz),
7.61-7.66 (m, 2H); 13C{1H}NMR (100 MHz, CDCl3): δ = 112.4, 116.6,
123.2, 123.7, 126.8, 127.1, 127.4, 128.3, 128.4 (2C), 128.8 (2C), 128.8,
130.3, 130.9, 137.8, 140.0, 141.3, 152.5, 155.8, 187.4; HRMS (ESI) Calcd
for C21H15O2 [M+H]+ = 299.1066, Found = 299.1065.
1
Mp: 104-106 °C; IR (neat) 1656, 1223, 832, 769, 604 cm-1; H-NMR (400
MHz, CDCl3): δ = 6.97 (t, 2H, J = 8.6 Hz), 7.15-7.22 (m, 4H), 7.41-7.51 (m,
3H), 7.55-7.62 (m, 1H), 7.64-7.69 (m, 2H); 13C{1H}NMR (100 MHz,
CDCl3): δ = 115.4 (d, JC-F = 21.6 Hz, 2C), 127.5, 128.5 (2C), 128.7, 130.0,
130.0, 130.1 (2C), 130.6, 132.5 (d, JC-F = 8.8 Hz, 2C), 133.6 (d, JC-F = 3.2
Hz), 138.5, 138.5, 139.7, 156.5 (d, JC-F = 242.6 Hz), 196.9; HRMS (ESI)
Calcd for C19H13ClFO [M+H]+ = 311.0634, Found = 311.0635.
p-Chlorophenyl o-(p-Chlorophenyl)phenyl Ketone (1Dg): white solid;
1
Mp: 98-100 °C; IR (neat) 1659, 1086, 829, 737 cm-1; H-NMR (400 MHz,
CDCl3): δ = 7.16-7.22 (m, 4H), 7.27 (d, 2H, J = 8.6 Hz), 7.44-7.50 (m, 3H),
7.56-7.61 (m, 3H); 13C{1H}NMR (100 MHz, CDCl3): δ = 127.5, 128.6 (2C),
128.6 (2C), 128.7, 130.0, 130.1 (2C), 130.7, 131.2 (2C), 133.7, 135.5,
138.3, 138.4, 139.6, 139.7, 197.2; HRMS (ESI) Calcd for C19H13Cl2O
[M+H]+ = 327.0338, Found = 327.0336.
o-(m-Methylphenyl)phenyl Phenyl Ketone (1Ea)10: white solid; Mp: 80-
82 °C; IR (neat) 1665, 1280, 754, 694 cm-1; 1H-NMR (400 MHz, CDCl3): δ
= 2.23 (s, 3H), 6.95 (d, 1H, J = 8.0 Hz), 7.02-7.09 (m, 3H), 7.25-7.29 (m,
2H), 7.38-7.59 (m, 5H), 7.63 (d, 2H, J = 8.2 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 21.2, 126.0, 126.9, 128.0 (2C), 128.0 (2C), 128.1, 128.7, 129.8
(2C), 130.0, 130.3, 132.7, 137.4, 137.7, 138.9, 140.0, 141.2, 198.9; HRMS
(ESI) Calcd for C20H17O [M+H]+ = 273.1273, Found = 273.1276.
o-(p-Methoxyphenyl)phenyl Phenyl Ketone (1Ca)10: white solid; Mp: 88-
90 °C; IR (neat) 1651, 1259, 924, 766, 608 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 3.72 (s, 3H), 6.73 (d, 2H, J = 8.6 Hz), 7.18 (d, 2H, J = 8.6 Hz),
7.26-7.30 (m, 2H), 7.40-7.49 (m, 4H), 7.56 (t, 1H, J = 8.2 Hz), 7.65 (d, 2H,
J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 55.0, 113.7 (2C), 126.5,
128.0 (2C), 128.6, 129.8 (2C), 129.9, 130.0 (2C), 130.2, 132.5, 132.8,
137.2, 138.7, 140.6, 158.8, 198.9; HRMS (ESI) Calcd for C20H17O2 [M+H]+
= 289.1222, Found = 289.1220.
Typical Procedure for Preparation of 6-Arylphenanthridines 3 from
Aryl Biaryl Ketones 1:
A toluene (1.0 mL) solution of o-(p-
methylphenyl)phenyl phenyl ketone 1Aa (272.4 mg, 1.0 mmol), TMS2NH
Submitted to the European Journal of Organic Chemistry
7
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201901278
European Journal of Organic Chemistry
(419.2 μL, 2.0 mmol), and Sc(OTf)3 (98.5 mg, 0.2 mmol) in a screw-
capped tube (30.0 mL) was heated at 90 °C for 15 h. After removal of the
solvent by evaporation, I2 (380.7 mg, 1.5 mmol) and K2CO3 (414.6 mg, 3.0
mmol) were added to a mixture of THF and MeOH (1 : 1, 4.0 mL) solution
of the residue. The mixture was stirred at 60 °C for 2 h. The reaction
mixture was quenched by sat. aq. Na2SO3, and extracted with AcOEt (3 ×
60.0 mL). The organic layer was washed with brine and dried over Na2SO4.
After filtration and removal of the solvent, the residue was treated by short
column chromatography on silica gel (hexane:AcOEt = 8:1) to give 3-
methyl-6-phenylphenanthridine 3Aa (218.2 mg, 81%).
130.5, 131.1 (2C), 133.4 134.7, 138.2, 139.1, 143.7, 159.8; HRMS (ESI)
Calcd for C20H15ClN [M+H]+ = 304.0888, Found = 304.0888.
6-(4’-Bromophenyl)-3-methylphenanthridine (3Ah): Yield: 271.6 mg
(78%); yellow solid; Mp: 167-169 °C; IR (neat) 1508, 1227, 833, 724 cm-1;
1H-NMR (400 MHz, CDCl3): δ = 2.61 (s, 3H), 7.52-7.64 (m, 4H), 7.70 (d,
2H, J = 8.6 Hz), 7.85 (t, 1H, J = 8.6 Hz), 8.03 (s, 1H), 8.04 (d, 1H, J = 8.4
Hz), 8.51 (d, 1H, J = 8.4 Hz), 8.67 (d, 1H, J = 8.4 Hz); 13C{1H}NMR (100
MHz, CDCl3): δ = 21.6, 121.4, 121.8, 122.1, 123.0, 124.6, 126.8, 128.4,
128.9, 129.8, 130.6, 131.4 (2C), 131.6 (2C), 133.5, 138.7, 139.2, 143.8,
159.9; HRMS (ESI) Calcd for C20H15BrN [M+H]+ = 348.0383, Found =
348.0378.
Phenyl o-(p-Methylphenyl)phenyl Ketimine (2Aa): white solid; 1H-NMR
(400 MHz, CDCl3): δ = 2.20 (s, 3H), 6.94 (d, 2H, J = 7.7 Hz), 7.05 (d, 2H,
J = 8.2 Hz), 7.28 (t, 2H, J = 8.2 Hz), 7.45 (t, 2H, J = 7.7 Hz), 7.52 (dd, 1H,
J = 7.7, 1.1 Hz), 7.60 (td, 1H, J = 7.7, 1.1 Hz), 7.69-7.75 (m, 3H), 7.91 (dd,
1H, J = 7.7, 1.1 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.0, 127.6,
128.6 (2C), 129.0 (2C), 129.1 (2C), 130.5, 130.7, 130.9, 131.3 (2C), 131.4,
133.3, 135.2, 136.1, 137.8, 143.2, 183.8.
3-Methyl-6-phenylphenanthridine (3Aa): Yield: 218.8 mg (81%); yellow
solid; Mp: 110-111 °C; IR (neat) 1559, 1444, 1362, 771, 700, 668 cm-1; 1H-
NMR (400 MHz, CDCl3): δ = 2.61 (s, 3H), 7.50-7.60 (m, 5H), 7.71-7.74 (m,
2H), 7.84 (t, 1H, J = 8.4 Hz), 8.05 (s, 1H), 8.09 (d, 1H, J = 8.4 Hz), 8.51 (d,
1H, J = 8.4 Hz), 8.67 (d, 1H, J = 8.4 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 21.5, 121.3, 121.6, 121.9, 124.8, 126.6, 128.3 (2C), 128.5,
128.6, 128.8, 129.6 (2C), 129.8, 130.4, 133.4, 138.9, 139.8, 143.8, 161.2;
HRMS (ESI) Calcd for C20H16N [M+H]+ = 270.1277, Found = 270.1274.
3-Methyl-6-(4’-methylphenyl)phenanthridine (3Ab): Yield: 198.5 mg
(70%); white solid; Mp: 90-91 °C; IR (neat) 1482, 1360, 1325, 820, 759,
726 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.48 (s, 3H), 2.60 (s, 3H), 7.36
(d, 2H, J = 8.4 Hz), 7.51 (d, 1H, J = 8.8 Hz), 7.57 (t, 1H, J = 8.0 Hz), 7.63
(d, 2H, J = 8.4 Hz), 7.83 (t, 1H, J = 8.0 Hz), 8.03 (s, 1H), 8.12 (d, 1H, J =
8.4 Hz), 8.49 (d, 1H, J = 8.4 Hz), 8.66 (d, 1H, J = 8.8 Hz); 13C{1H}NMR
(100 MHz, CDCl3): δ = 21.3, 21.5, 121.3, 121.6, 121.9, 124.9, 126.5, 128.5,
128.9, 129.0 (2C), 129.6 (2C), 129.8, 130.3, 133.4, 137.0, 138.4, 138.8,
143.9, 161.2; HRMS (ESI) Calcd for C21H18N [M+H]+ = 284.1434, Found
= 284.1429.
3-Methyl-6-(3’-methylphenyl)phenanthridine (3Ac): Yield: 215.2 mg
(76%); white solid; Mp: 65-68 °C; IR (neat) 1561, 1480, 1361, 768, 729,
709 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.47 (s, 3H), 2.60 (s, 3H), 7.33
(d, 1H, J = 7.6 Hz), 7.43 (t, 1H, J = 7.6 Hz), 7.49-7.60 (m, 4H), 7.83 (t, 1H,
J = 7.6 Hz), 8.05 (s, 1H), 8.09 (d, 1H, J = 8.3 Hz), 8.50 (d, 1H, J = 8.3 Hz),
8.66 (d, 1H, J = 8.3 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.5, 21.5,
121.3, 121.6, 121.8, 124.9, 126.5, 126.8, 128.0, 128.5, 128.8, 129.3, 129.8,
130.2, 130.3, 133.3, 138.0, 138.8, 139.7, 143.8, 161.3; HRMS (ESI) Calcd
for C21H18N [M+H]+ = 284.1434, Found = 284.1429.
3-Methyl-6-(2’-methylphenyl)phenanthridine (3Ad): Yield: 132.0 mg
(47%); yellow solid; Mp: 65-66 °C; IR (neat) 1479, 1362, 1328, 768, 745,
727 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.11 (s, 3H), 2.61 (s, 3H), 7.33-
7.44 (m, 4H), 7.51-7.55 (m, 2H), 7.68 (d, 1H, J = 7.7 Hz), 7.83 (t, 1H, J =
7.7 Hz), 8.04 (s, 1H), 8.53 (d, 1H, J = 8.4 Hz), 8.66 (d, 1H, J = 8.4 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 19.8, 21.6, 121.4, 121.8, 121.9,
125.5, 125.7, 126.8, 128.5, 128.6, 128.7, 129.2, 129.8, 130.3, 130.5, 133.0,
136.4, 139.0, 139.3, 143.9, 161.9; HRMS (ESI) Calcd for C21H18N [M+H]+
= 284.1434, Found = 284.1432.
6-(4’-Methoxyphenyl)-3-methylphenanthridine (3Ae): Yield: 217.3 mg
(72%); yellow solid; Mp: 154-155 °C; IR (neat) 1249, 1173, 1021, 835, 730,
506 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.60 (s, 3H), 3.92 (s, 3H), 7.09
(d, 2H, J = 8.8 Hz), 7.51 (d, 1H, J = 8.8 Hz), 7.59 (t, 1H, J = 8.0 Hz), 7.70
(d, 2H, J = 8.8 Hz), 7.84 (t, 1H, J = 8.0 Hz), 8.03 (s, 1H), 8.14 (d, 1H, J =
8.0 Hz), 8.49 (d, 1H, J = 8.8 Hz), 8.66 (d, 1H, J = 8.0 Hz); 13C{1H}NMR
(100 MHz, CDCl3): δ = 21.5, 55.4, 113.8 (2C), 121.2, 121.7, 122.0, 124.9,
126.5, 128.4, 128.8, 129.7, 130.3, 131.1 (2C), 132.3, 133.5, 138.9, 144.1,
160.0, 160.8; HRMS (ESI) Calcd for C21H18NO [M+H]+ = 300.1383, Found
= 300.1383.
6-(4’-Fluorophenyl)-3-methylphenanthridine (3Af): Yield: 221.2 mg
(77%); white solid; Mp: 112-115 °C; IR (neat) 1513, 1220, 1149, 759, 726,
672 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.61 (s, 3H), 7.25 (t, 2H, J = 8.5
Hz), 7.53 (d, 1H, J = 6.7 Hz), 7.60 (t, 1H, J = 6.7 Hz), 7.70-7.75 (m, 2H),
7.85 (t, 1H, J = 7.2 Hz), 8.03 (s, 1H), 8.05 (d, 1H, J = 8.3 Hz), 8.51 (d, 1H,
J = 8.6 Hz), 8.67 (d, 1H, J = 8.6 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =
21.5, 115.4 (d, JC-F = 21.6 Hz, 2C), 121.3, 121.7, 122.1, 124.8, 126.7, 128.5,
128.8, 129.8, 130.5, 131.6 (d, JC-F = 8.5 Hz, 2C), 133.5, 135.9 (d, JC-F = 2.9
Hz), 139.1, 143.5, 160.1, 163.1 (d, JC-F = 252.8 Hz); HRMS (ESI) Calcd for
C20H15FN [M+H]+ = 288.1183, Found = 288.1178.
3-Methyl-6-(naphthalen-2’-yl)phenanthridine (3Ai): Yield: 255.5 mg
(80%); white solid; Mp: 122-125 °C; IR (neat) 1478, 1012, 824, 759, 725
cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.62 (s, 3H), 7.51-7.60 (m, 4H),
7.84 (d, 1H, J = 8.1 Hz), 7.86 (d, 1H, J = 8.1 Hz), 7.95-7.97 (m, 2H), 8.03
(d, 1H, J = 8.4 Hz), 8.08 (s, 1H), 8.14 (d, 1H, J = 8.2 Hz), 8.22 (s, 1H), 8.53
(d, 1H, J = 8.4 Hz), 8.69 (d, 1H, J = 8.2 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ =21.5, 121.3, 121.6, 121.9, 124.9, 126.3, 126.4, 126.5, 127.3,
127.7, 127.9, 128.4, 128.6, 128.7, 129.1, 129.8, 130.3, 133.1, 133.2, 133.4,
137.2, 138.9, 143.9, 161.0; HRMS (ESI) Calcd for C24H18N [M+H]+
320.1434, Found = 320.1429.
=
6-(Benzo[b]thiophen-2’-yl)-3-methylphenanthridine (3Aj): Yield: 198.5
mg (61%); white solid; Mp: 118-120 °C; IR (neat) 1484, 861, 763, 679 cm-
1; 1H-NMR (400 MHz, CDCl3): δ = 2.61 (s, 3H), 7.39-7.45 (m, 2H), 7.53 (d,
1H, J = 8.3 Hz), 7.69 (t, 1H, J = 7.6 Hz), 7.86-7.97 (m, 4H), 8.05 (s, 1H),
8.49 (d, 1H, J = 8.3 Hz), 8.64 (d, 1H, J = 8.3 Hz) , 8.68 (d, 1H, J = 7.6 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 21.5, 121.2, 121.6, 122.1, 122.2,
124.2, 124.3, 124.4, 125.0, 125.8, 127.0, 127.8, 129.0, 129.8, 130.5, 133.5,
139.0, 140.0, 140.6, 142.8, 143.7, 153.8; HRMS (ESI) Calcd for C22H16NS
[M+H]+ = 326.0998, Found = 326.0993.
6-(Benzofuran-2’-yl)-3-methylphenanthridine (3Ak): Yield: 216.6 mg
(70%); white solid; Mp: 125-126 °C; IR (neat) 1480, 1154, 837, 748, 666
cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.62 (s, 3H), 7.33 (t, 1H, J = 7.7 Hz),
7.41 (t, 1H, J = 7.7 Hz), 7.54 (d, 1H, J = 8.5 Hz), 7.57 (s, 1H), 7.69-7.75 (m,
3H), 7.89 (t, 1H, J = 8.5 Hz), 8.09 (s, 1H), 8.51 (d, 1H, J = 8.5 Hz), 8.69 (d,
1H, J = 8.5 Hz) , 8.86 (d, 1H, J = 7.7 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 21.5, 109.4, 111.9, 121.6, 121.7 (2C), 122.1, 123.3, 124.2,
125.3, 127.2, 127.8, 128.3, 129.3, 130.0, 130.7, 133.7, 139.1, 143.8, 149.8,
155.0, 155.5; HRMS (ESI) Calcd for C22H16NO [M+H]+ = 310.1226, Found
= 310.1223.
6-(4’-tert-Butylphenyl)-3-methylphenanthridine (3Al): Yield: 266.9 mg
(82%); white solid; Mp: 70-72 °C; IR (neat) 1482, 1361, 769, 608 cm-1; 1H-
NMR (400 MHz, CDCl3): δ = 1.41 (s, 9H), 2.60 (s, 3H), 7.51 (d, 1H, J =
8.8 Hz), 7.56-7.60 (m, 3H), 7.68 (d, 2H, J = 8.4 Hz), 7.84 (t, 1H, J = 7.7
Hz), 8.04 (s, 1H), 8.17 (d, 1H, J = 8.8 Hz), 8.50 (d, 1H, J = 8.2 Hz), 8.66 (d,
1H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.5, 31.3 (3C),
34.6, 121.2, 121.6, 121.8, 124.8, 125.3 (2C), 126.4, 128.4, 128.9, 129.4
(2C), 129.8, 130.2, 133.3, 136.9, 138.7, 143.9, 151.5, 161.1; HRMS (ESI)
Calcd for C24H24N [M+H]+ = 326.1903, Found = 326.1903.
6-Phenylphenanthridine (3Ba) Yield: 208.4 mg (92%); yellow solid; Mp:
99-101 °C; IR (neat) 1360, 1137, 960, 1758, 695 cm-1; 1H-NMR (400 MHz,
CDCl3): δ = 7.51-7.66 (m, 4H), 7.68-7.79 (m, 4H), 7.87 (td, 1H, J = 7.6, 1.4
Hz), 8.11 (d, 1H, J = 8.4Hz), 8.25 (d, 1H, J = 8.4, 1.4 Hz), 8.64 (dd, 1H, J =
8.4, 1.4 Hz), 8.72 (d, 1H, J = 8.4 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ
= 121.8, 122.1, 123.6, 125.1, 126.8, 127.0, 128.3 (2C), 128.6, 128.7, 128.8,
129.6 (2C), 130.2, 130.4, 133.3, 139.7, 143.7, 161.1;HRMS (ESI) Calcd for
C19H14N [M+H]+ = 256.1121, Found = 256.1121.
6-(4’-Methylphenyl)phenanthridine (3Bb) Yield: 183.5 mg (68%); white
solid; Mp: 80-82 °C; IR (neat) 1357, 960, 822, 754, 726 cm-1; 1H-NMR
(400 MHz, CDCl3): 2.48 (s, 3H), 7.37 (d, 2H, J = 8.4 Hz), 7.60-7.71 (m,
4H), 7.75 (td, 1H, J = 7.6, 1.4 Hz), 7.86 (td, 1H, J = 7.6, 1.1 Hz), 8.14 (d,
1H, J = 8.4 Hz), 8.24 (dd, 1H, J = 8.4, 1.1 Hz), 8.62 (dd, 1H, J = 8.4, 1.4
Hz), 8.71 (d, 1H, J = 8.4 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.3,
121.8, 122.1, 123.6, 125.2, 126.7, 127.0, 128.7, 128.9, 129.0 (2C), 129.6
(2C), 130.2, 130.4, 133.3, 136.9, 138.5, 143.7, 161.2; HRMS (ESI) Calcd
for C20H16N [M+H]+ = 270.1277, Found = 270.1273.
6-(4’-Methoxyphenyl)phenanthridine (3Be): Yield: 185.6 mg (72%);
yellow solid; Mp: 144-146 °C; IR (neat) 1509, 1247, 1171, 1028, 828, 759
1
cm-1; H-NMR (400 MHz, CDCl3): δ = 3.92 (s, 3H), 7.09 (d, 2H, J = 8.4
Hz), 7.60-7.77 (m, 5H), 7.82 (t, 1H, J = 8.4 Hz), 8.16 (d, 1H, J = 8.4 Hz),
8.23 (d, 1H, J = 8.4 Hz), 8.60 (d, 1H, J = 8.4 Hz), 8.70 (d, 1H, J = 8.4 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 55.4, 113.8 (2C), 121.8, 122.1, 123.5,
125.2, 126.6, 127.0, 128.7, 128.8, 130.2, 130.3, 131.1 (2C), 132.2, 133.4,
143.8, 160.3, 160.8; HRMS (ESI) Calcd for C20H16NO [M+H]+ = 286.1226,
Found = 286.1227.
6-(4’-Fluorophenyl)phenanthridine (3Bf): Yield: 191.3 mg (70%); white
solid; Mp: 118-120 °C; IR (neat) 1508, 1217, 834, 751 cm-1; 1H-NMR (400
MHz, CDCl3): δ = 7.22-7.30 (m, 2H), 7.64 (t, 1H, J = 8.1 Hz), 7.69-7.80 (m,
4H), 7.88 (t, 1H, J = 8.3 Hz), 8.08 (d, 1H, J = 8.3 Hz), 8.23 (d, 1H, J = 9.4
6-(4’-Chlorophenyl)-3-methylphenanthridine (3Ag): Yield: 211.7 mg
(70%); yellow solid; Mp: 170-171 °C; IR (neat) 1479, 1361, 827, 759, 725
cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.60 (s, 3H), 7.52-7.61 (m, 4H),
7.66-7.69 (m, 2H), 7.82-7.86 (m, 1H), 8.03 (d, 2H, J = 9.6 Hz), 8.50 (d, 1H,
J = 8.8 Hz), 8.66 (d, 1H, J = 8.8 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =
21.5, 121.3, 121.7, 122.0, 124.6, 126.7, 128.3, 128.6 (2C), 128.8, 129.8,
Submitted to the European Journal of Organic Chemistry
8
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201901278
European Journal of Organic Chemistry
Hz), 8.64 (d, 1H, J = 8.1 Hz), 8.73 (d, 1H, J = 8.3 Hz); 13C{1H}NMR (100
MHz, CDCl3): δ = 115.3 (d, JC-F = 21.6 Hz, 2C), 121.8, 122.2, 123.6, 125.0,
126.9, 127.1, 128.4, 128.8, 130.2, 130.5, 131.5 (d, JC-F = 8.5 Hz, 2C), 133.3,
135.7 (d, JC-F = 2.8 Hz), 143.6, 160.0, 163.0 (d, JC-F = 248.1 Hz); HRMS
(ESI) Calcd for C19H13FN [M+H]+ = 274.1027, Found = 274.1023.
(d, JC-F = 3.8 Hz), 145.3, 160.3, 160.6, 163.1 (d, JC-F = 248.1 Hz); HRMS
(ESI) Calcd for C20H15FNO [M+H]+ = 304.1132, Found = 304.1128.
6-(4’-Chlorophenyl)-3-methoxyphenanthridine (3Cg): Yield: 223.9 mg
(70%); white solid; Mp: 143-145 °C; IR (neat) 1617, 1204, 1044, 757, 719,
1
502 cm-1; H-NMR (400 MHz, CDCl3): δ = 3.98 (s, 3H), 7.33 (dd, 1H, J =
6-(4’-Chlorophenyl)phenanthridine (3Bg): Yield: 227.5 mg (79%);
yellow solid; Mp: 151-152 °C; IR (neat) 1359, 1089, 1014, 829, 752, 722
8.4, 2.8 Hz), 7.52-7.69 (m, 6H), 7.84 (t, 1H, J = 7.2 Hz), 8.02 (d, 1H, J =
8.4 Hz), 8.51 (d, 1H, J = 8.4 Hz), 8.61 (d, 1H, J = 8.4 Hz); 13C{1H}NMR
(100 MHz, CDCl3): δ = 55.5, 110.0, 117.7, 118.3, 121.7, 123.1, 123.9,
126.1, 128.4 , 128.6 (2C), 130.7, 131.0 (2C), 133.6, 134.8, 138.2, 145.2,
160.2, 160.3; HRMS (ESI) Calcd for C20H15ClNO[M+H]+ = 320.0837,
Found = 320.0834.
3-Chloro-6-phenylphenanthridine (3Da): Yield: 173.9 mg (60%); yellow
solid; Mp: 132-134 °C; IR (neat) 1443, 1360, 1074, 765, 668 cm-1;1H-NMR
(400 MHz, CDCl3): δ = 7.51-7.65 (m, 5H), 7.70-7.75 (m, 2H), 7.87 (t, 1H, J
= 8.8 Hz), 8.12 (d, 1H, J = 9.2 Hz). 8.24 (d, 1H, J = 2.4 Hz), 8.53 (d, 1H, J
= 9.2 Hz), 8.64 (d, 1H, J = 8.8 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =
122.1, 122.2, 123.3, 125.1, 127.4 (2C), 128.4 (2C), 128.9, 129.0, 129.5,
129.6 (2C), 130.9, 133.0, 134.4, 139.3, 144.4, 162.4; HRMS (ESI) Calcd
for C19H13ClN [M+H]+ = 290.0731, Found = 290.0730.
1
cm-1; H-NMR (400 MHz, CDCl3): δ = 7.51-7.56 (m, 2H), 7.62-7.79 (m,
5H), 7.88 (t, 1H, J = 7.6 Hz), 8.07 (d, 1H, J = 8.8 Hz), 8.23 (d, 1H, J = 8.4
Hz), 8.63 (d, 1H, J = 8.4 Hz), 8.72 (d, 1H, J = 8.8 Hz); 13C{1H}NMR (100
MHz, CDCl3): δ = 122.0, 122.3, 123.7, 124.4, 127.1, 127.4, 128.4, 128.6
(2C), 128.9, 130.3, 130.6, 131.1 (2C), 133.4, 134.8, 138.1, 143.6, 159.9;
HRMS (ESI) Calcd for C19H13ClN [M+H]+ = 290.0731, Found = 290.0728.
6-(Naphthalen-2’-yl)phenanthridine (3Bi): Yield: 271.8 mg (89%); white
1
solid; Mp: 148-151 °C; IR (neat) 758, 741, 724, 681 cm-1; H-NMR (400
MHz, CDCl3): δ = 7.55-7.65 (m, 3H), 7.72 (t, 1H, J = 7.9 Hz), 7.79 (t, 1H, J
= 7.9 Hz), 7.86-7.91 (m, 2H), 7.95-7.97 (m, 2H), 8.04 (d, 1H, J = 8.6 Hz),
8.16 (d, 1H, J = 8.2 Hz), 8.24 (s, 1H), 8.28 (d, 1H, J = 7.9 Hz), 8.66 (d, 1H,
J = 7.9 Hz), 8.74 (d, 1H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ =
122.0, 122.2, 123.7, 125.3, 126.4, 126.6, 127.0, 127.2, 127.3, 127.8, 128.1,
128.5, 128.9, 128.9, 129.2, 130.3, 130.6, 133.2, 133.3, 133.5, 137.2, 143.8,
161.2; HRMS (ESI) Calcd for C23H16N [M+H]+ = 306.1277, Found =
306.1274.
3-Chloro-6-(4’-methylphenyl)phenanthridine (3Db): Yield: 212.7 mg
(70%); white solid; Mp: 128-129 °C; IR (neat) 1078, 905, 819, 746, 719,
1
671 cm-1; H-NMR (400 MHz, CDCl3): δ = 2.48 (s, 3H), 7.37 (d, 2H, J =
8.0 Hz), 7.65-7.10 (m, 4H), 7.86 (t, 1H, J = 8.0 Hz), 8.15 (d, 1H, J = 8.4
Hz), 8.22 (d, 1H, J = 2.0 Hz), 8.52 (d, 1H, J = 8.8 Hz), 8.63 (d, 1H, J = 8.4
Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.4, 122.0, 122.1, 123.2, 125.1,
127.2, 127.3, 129.1 (3C), 129.4, 129.6 (2C), 130.8, 133.0, 134.3, 136.4,
138.9, 144.4, 162.4; HRMS (ESI) Calcd for C20H15ClN [M+H]+ = 304.0888,
Found = 304.0887.
6-(Benzo[b]thiophen-2’-yl)phenanthridine (3Bj): Yield: 205.5 mg
(66%); orange solid; Mp: 153-156 °C; IR (neat) 1356, 907, 765, 742, 721
1
cm-1; H-NMR (400 MHz, CDCl3): δ = 7.41-7.46 (m, 2H), 7.69-7.80 (m,
3H), 7.87 (s, 1H), 7.90-7.97 (m, 3H), 8.25 (d, 1H, J = 8.1 Hz), 8.62 (d, 1H,
J = 8.1 Hz), 8.67 (d, 1H, J = 8.1 Hz), 8.74 (d, 1H, J = 8.3 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 121.9, 122.3, 122.4, 123.6, 124.3,
124.5, 124.8, 125.2, 126.0, 127.4, 127.6, 128.0, 129.0, 130.4, 130.8, 133.6,
140.0, 140.7, 142.6, 143.6, 154.1; HRMS (ESI) Calcd for C21H14NS
[M+H]+ = 312.0841, Found = 312.0837.
6-(Benzofuran-2’-yl)phenanthridine (3Bk): Yield: 197.9 mg (67%);
yellow solid; Mp: 138-140 °C; IR (neat) 1314, 745, 685 cm-1; 1H-NMR
(400 MHz, CDCl3): δ = 7.34 (t, 1H, J = 7.7 Hz), 7.42 (t, 1H, J = 7.7 Hz),
7.59 (s, 1H), 7.70-7.79 (m, 5H), 7.92 (t, 1H, J = 7.7 Hz), 8.29 (d, 1H, J =
9.1 Hz), 8.63 (d, 1H, J = 9.1 Hz) , 8.74 (d, 1H, J = 7.7 Hz), 8.89 (d, 1H, J =
9.1 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 109.6, 111.9, 121.8, 122.0,
122.3, 123.3, 123.9, 124.5, 125.4, 127.5, 127.7, 127.9, 128.3, 129.0, 130.5,
130.7, 133.6, 144.0, 149.8, 154.8, 155.5; HRMS (ESI) Calcd for C21H14NO
[M+H]+ = 296.1070, Found = 296.1067.
3-Chloro-6-(4’-methoxyphenyl)phenanthridine (3De): Yield: 275.0 mg
(86%); white solid; Mp: 133-135 °C; IR (neat) 1360, 1248, 1031, 828, 761,
1
598 cm-1; H-NMR (400 MHz, CDCl3): δ = 3.92 (s, 3H), 7.10 (d, 2H, J =
8.8 Hz), 7.61-7.72 (m, 4H), 7.88 (t, 1H, J = 8.4 Hz), 8.18 (d, 1H, J = 8.4
Hz), 8.21 (d, 1H, J = 2.4 Hz), 8.52 (d, 1H, J = 8.8 Hz), 8.63 (d, 1H, J = 8.4
Hz), 13C{1H}NMR (100 MHz, CDCl3): δ = 55.3, 113.8 (2C), 121.9, 122.0,
123.2, 125.1, 127.1, 127.2, 129.0, 129.3, 130.7, 131.2 (2C), 131.7, 132.9,
134.2, 144.4, 160.2, 161.9; HRMS (ESI) Calcd for C20H15ClNO [M+H]+ =
320.0837, Found = 320.0836.
3-Chloro-6-(4’-fluorophenyl)phenanthridine (3Df): Yield: 203.1 mg
(66%); white solid; Mp: 172-175 °C; IR (neat) 1502, 1208, 826, 736 cm-1;
1H-NMR (400 MHz, CDCl3): δ = 7.24-7.30 (m, 2H), 7.63-7.67 (m, 2H),
7.70-7.75 (m, 2H), 7.89 (t, 1H, J = 7.7 Hz), 8.09 (d, 1H, J = 8.4 Hz), 8.22
(d, 1H, J = 2.0 Hz), 8.53 (d, 1H, J = 8.4 Hz), 8.65 (d, 1H, J = 8.4 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 115.5 (d, JC-F = 21.6 Hz, 2C), 122.2,
122.2, 123.4, 125.0, 127.5, 127.6, 128.8, 129.5, 131.1, 131.6 (d, JC-F = 8.5
Hz, 2C), 133.1, 134.5, 135.4 (d, JC-F = 2.8 Hz), 144.4, 161.3, 163.3 (d, JC-F
= 249.0 Hz); HRMS (ESI) Calcd for C19H12ClFN [M+H]+ = 308.0637,
Found = 308.0633.
3-Methoxy-6-phenylphenanthridine (3Ca): Yield: 185.5 mg (65%);
yellow solid; Mp: 107-108 °C; IR (neat) 1617, 1203, 1035, 768, 706, 673
1
cm-1; H-NMR (400 MHz, CDCl3): δ = 3.98 (s, 3H), 7.32 (dd, 1H, J = 9.2,
2.8 Hz), 7.50-7.59 (m, 4H), 7.66 (d, 1H, J = 2.8 Hz), 7.71-7.74 (m, 2H),
7.81 (t, 1H, J = 7.8 Hz), 8.06 (d, 1H, J = 8.4 Hz), 8.50 (d, 1H, J = 9.2 Hz),
8.60 (d, 1H, J = 8.0 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 55.3, 109.7,
117.5, 117.9, 121.4, 122.9, 124.0, 125.7, 128.2 (2C), 128.4, 128.6, 129.5
(2C), 130.3, 133.6, 139.6, 145.1, 160.0, 161.4; HRMS (ESI) Calcd for
C20H16NO [M+H]+ = 286.1226, Found = 286.1225.
3-Chloro-6-(4’-chlorophenyl)phenanthridine (3Dg): Yield: 239.9 mg
(74%); white solid; Mp: 210-212 °C; IR (neat) 1359, 1078, 831, 765, 722
1
cm-1; H-NMR (400 MHz, DMSO-d6): δ = 7.72 (d, 2H, J = 8.4 Hz), 7.83-
7.93 (m, 4H), 8.13 (d, 1H, J = 8.4 Hz), 8.19 (t, 1H, J = 8.4 Hz), 8.26 (d, 1H,
J = 2.0 Hz), 8.97 (d, 1H, J = 9.2 Hz), 9.02 (d, 1H, J = 8.4Hz);
13C{1H}NMR (100 MHz, CDCl3 and CF3CO2H): δ = 121.1, 123.1, 123.2,
123.3, 124.6, 127.4, 130.0 (2C), 130.7, 131.3 (2C), 131.8, 132.2, 133.3,
135.8, 138.1, 139.0, 140.4, 160.6; HRMS (ESI) Calcd for C19H12Cl2N
[M+H]+ = 324.0341, Found = 324.0340.
3-Methoxy-6-(4’-methylphenyl)phenanthridine (3Cb): Yield: 209.6 mg
(70%); white solid; Mp: 118-120 °C; IR (neat) 1203, 1039, 821, 760, 721,
599cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.48 (s, 3H), 3.98 (s, 3H), 7.32
(dd, 1H, J = 9.2, 2.8 Hz), 7.37 (d, 2H, J = 8.0 Hz), 7.54 (t, 1H, J = 8.0 Hz),
7.61-7.65 (m, 3H), 7.81 (t, 1H, J = 8.0 Hz), 8.10 (d, 1H, J = 8.4 Hz), 8.50
(d, 1H, J = 9.0 Hz), 8.59 (d, 1H, J = 8.0 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 21.2, 55.3, 109.7, 117.5, 117.7, 121.4, 122.9, 124.1, 125.7,
128.7, 128.9 (2C), 129.4 (2C), 130.2, 133.4, 136.8, 138.2, 145.2, 159.9,
161.5; HRMS (ESI) Calcd for C21H18NO [M+H]+ = 300.1383, Found =
300.1379.
4-Methyl-6-phenylphenanthridine (3Ea). Yield: 221.1 mg (78%); pale
yellow solid; Mp: 108−110 °C; IR (neat) 1566, 1466, 1360, 744, 687, 667
1
cm-1 ; H NMR (400 MHz, CDCl3): δ = 2.88 (s. 3H), 7.50-7.62 (m, 6 H),
7.80-7.84 (m, 3 H), 8.18 (d, 1H, J = 8.4 Hz), 8.46 (d, 1H, J = 8.0 Hz), 8.69
(d, 1H, J = 8.4 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 18.4, 119.6,
122.4, 123.4, 124.7, 126.4, 126.8, 128.2 (2C), 128.5, 128.6, 129.4, 130.1,
130.2 (2C), 133.8, 138.2, 140.2, 142.5, 159.2; HRMS (ESI) Calcd for
C20H16N [M + H]+ = 270.1277, Found = 270.1278.
3-Methoxy-6-(4’-methoxyphenyl)phenanthridine (3Ce): Yield: 220.8 mg
(70%); white solid; Mp: 141-143 °C; IR (neat) 1607, 1244, 1027, 832, 766
1
cm-1; H-NMR (400 MHz, CDCl3): δ = 3.92 (s, 3H), 3.98 (s, 3H), 7.07-
7.11 (m, 2H), 7.31 (dd, 1H, J = 8.4, 2.8 Hz), 7.55 (t, 1H, J = 7.8 Hz), 7.64
(d, 1H, J = 2.4 Hz), 7.68-7.71 (m, 2H), 7.82 (t, 1H, J = 7.8 Hz), 8.13 (d, 1H,
J = 8.4 Hz), 8.50 (d, 1H, J = 8.4 Hz), 8.59 (d, 1H, J = 8.4 Hz);
13C{1H}NMR (100 MHz, CDCl3): δ = 55.1, 55.2, 109.6, 113.6 (2C), 117.3,
117.6, 121.4, 122.8, 124.5, 125.6, 128.6, 130.1, 130.9 (2C), 132.1, 133.4,
Transformation of 6-(4’-Bromophenyl)-3-methylphenanthridine 3Ah
(I): n-BuLi (1.55 M solution in hexane, 0.71 mL, 1.1 mmol) was added
dropwise to a solution of 3Ah (348.2 mg, 1.0 mmol) in THF (6.0 mL) at -
50 °C under Ar atomosphere. After 30 min, DMF (125.4 μL, 1.5 mmol)
was added, the obtained mixture was gradually warmed to room
temperature, and then the reaction mixture was stirred at room temperature
for 2 h. The reaction mixture was quenched by sat. aq. NH4Cl and was
extracted with AcOEt (3 × 60.0 mL). The organic layer was washed with
brine and dried over Na2SO4. After filtration and removal of the solvent,
the residue was purified by short column chromatography on silica gel
(hexane:AcOEt = 4:1) to give 6-(4’-formylphenyl)-3-methylphenanthridine
4A-1 (202.2 mg, 68%).
145.2, 159.8, 159.9, 161.0; HRMS (ESI) Calcd for C21H18NO2 [M+H]+
316.1332, Found = 316.1331.
=
6-(4’-Fluorophenyl)-3-methoxyphenanthridine (3Cf): Yield: 197.2 mg
(65%); white solid; Mp: 117-120 °C; IR (neat) 1510, 1218, 1149, 759, 672
cm-1; 1H-NMR (400 MHz, CDCl3): δ = 3.99 (s, 3H), 7.23-7.29 (m, 2H),
7.34 (dd, 1H, J = 9.1, 2.7 Hz), 7.56 (t, 1H, J = 7.6 Hz), 7.64 (d, 1H, J = 2.7
Hz), 7.70-7.75 (m, 2H), 7.84 (t, 1H, J = 7.6 Hz), 8.04 (d, 1H, J = 8.4 Hz),
8.51 (d, 1H, J = 9.1 Hz), 8.61 (d, 1H, J = 8.4 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 55.6, 109.8, 115.4 (d, JC-F = 21.6 Hz, 2C), 117.8, 118.3, 121.8,
123.2, 124.2, 126.1, 128.6, 130.7, 131.5 (d, JC-F = 8.5 Hz, 2C), 133.7, 135.9
6-(4’-Formylphenyl)-3-methylphenanthridine (4A-1): Yield: 202.1 mg
(68%); white solid; Mp: 173-175 °C; IR (neat) 1697, 1606, 1209, 830, 762
cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.62 (s, 3H), 7.54-7.63 (m, 2H),
Submitted to the European Journal of Organic Chemistry
9
This article is protected by copyright. All rights reserved.

10.1002/ejoc.201901278
European Journal of Organic Chemistry
7.88 (t, 1H, J = 8.2 Hz), 7.92 (d, 2H, J = 8.2 Hz), 8.00 (d, 1H, J = 7.9 Hz),
8.04 (s, 1H), 8.09 (d, 2H, J = 8.2 Hz), 8.53 (d, 1H, J = 8.2 Hz), 8.70 (d, 1H,
J = 7.9 Hz), 10.17 (s, 1H); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.7,
121.6, 121.9, 122.3, 124.6, 127.0, 128.3, 129.3, 129.9 (2C), 130.0, 130.6
(2C), 130.9, 133.7, 136.3, 139.4, 143.9, 146.0, 159.8, 192.2; HRMS (ESI)
Calcd for C21H16NO [M+H]+ = 298.1227, Found = 298.1224.
Transformation of 6-(4’-Bromophenyl)-3-methylphenanthridine 3Ah
(II): To a mixture of 3Ah (348.2 mg, 1.0 mmol), K2CO3 (3.0 mmol, 207.4
mg), CuI (0.04 mmol, 38.4 mg), and DMEDA (0.080 mmol, 40 μL) in
toluene (12.0 mL) was added p-methoxybenzamide (2.4 mmol, 181.4 mg)
under argon atmosphere. The obtained mixture was stirred at 130 °C for 18
h. Then, sat. aq. NaHCO3 (10.0 mL) was added to the reaction mixture,
and the product was extracted with CHCl3 (30.0 mL × 3). The organic
layer was dried over Na2SO4. After filtration and removal of the solvent
under reduced pressure, the residue was purified by column
chromatography on silica gel (hexane : CHCl3 = 1 : 1) to give N-[4’-(3“-
methylphenanthridin-6“-yl)phenyl]-4-methoxybenzamide 4A-2 (251.1 mg,
60% yield).
Acknowledgments
This work was supported by JSPS KAKENHI Grant Number JP15K05418
in Japan.
____________
[1] (a) T. Nakanishi, M. Suzuki, J. Nat. Prod., 1998, 61, 1263-1267. (b)
T. Nakanishi, M. Suzuki, A. Mashiba, K. Ishikawa, T. Yokotsuka, J.
Org. Chem., 1998, 63, 4235-4239. (c) T. Nakanishi, M. Suzuki, A.
Saimoto, T. Kabasawa, J. Nat. Prod., 1999, 62, 864-867. (d) T.
Nakanishi, A. Masuda, M. Suwa, Y. Akiyama, N. Hoshino-Abe, M.
Suzuki, Bioorg. Med. Chem. Lett. 2000, 10, 2321-2323. (e) T.
Ishikawa, Med. Res. Rev., 2001, 21, 61-72. (f) W. A. Denny, Curr.
Med. Chem. 2002, 9, 1655-1665.
[2] (a) A. A. Ali, H. M. El Sayed, O M. Abdallah, W. Steglich,
Phytochemistry, 1986, 25, 2399-2401. (b) B. D. Krane, M. O.
Fagbule, M. Shamma, J. Nat. Prod., 1984, 47, 1-43. (c) F. Viladomat,
M. Sellés, C. Codina, J. Bastida, J. Planta Med., 1997, 63, 583. (d) O.
B. Abdel-Halim, T. Morikawa, S. Ando, H. Matsuda and M.
Yoshikawa, J. Nat. Prod., 2004, 67, 1119-1124. (e) L. Sripada, J. A.
Teske, A. Deiters, Org. Biomol. Chem. 2008, 6, 263-235. (e) A. M.
Linsenmeier, C. W. Williams, S. Bräse, J. Org. Chem., 2011, 76,
9127-9132.
N-[4’-(3“-Methylphenanthridin-6“-yl)phenyl]-4-methoxybenzamide
(4A-2): Yield: 251.1 mg (60%); orange solid; Mp: 228-230 °C; IR (neat)
1
3274, 1645, 1606, 1253, 766, 611 cm-1; H-NMR (400 MHz, CDCl3): δ =
2.61 (s, 3H), 3.90 (s, 3H), 7.01 (d, 2H, J = 8.8 Hz), 7.52 (d, 1H, J = 8.4 Hz),
7.60 (t, 1H, J = 7.3 Hz), 7.76-7.92 (m, 7H), 8.04 (s, 1H), 8.15 (d, 1H, J =
8.2 Hz), 8.51 (d, 1H, J = 8.4 Hz), 8.67 (d, 1H, J = 8.4 Hz); 13C{1H}NMR
(100 MHz, CDCl3): δ = 21.6, 35.5, 114.0 (2C), 119.9 (2C), 121.4, 121.7,
122.0, 124.9, 126.7, 127.0, 128.6, 128.8, 129.0 (2C), 129.8, 130.5, 130.6
(2C), 133.5, 135.8, 138.6, 139.0, 143.9, 160.6, 162.6, 165.3; HRMS (ESI)
Calcd for C28H23N2O2 [M+H]+ = 419.1754, Found = 419.1753.
Transformation of 6-(4’-Bromophenyl)-3-methylphenanthridine 3Ah
(III): To a mixture of 3Ah (348.2 mg, 1.0 mmol) and phenylboronic acid
(146.4 mg, 1.2 mmol) in DMF (10.0 mL) was added PdCl2(PPh3)2 (280.8
mg, 0.04 mmol) under argon atmosphere. The obtained mixture was stirred
at room temperature for 30 min. Then, K2CO3 (138.2 mg, 1.0 mmol) in
H2O (2 mL) was added to the mixture, and the obtained mixture was stirred
at 70 °C for 5.5. h. Then, water (20.0 mL) was added to the reaction
mixture, and the product was extracted with a mixture of hexane and
AcOEt ( 4 : 1, 30.0 mL × 3). The organic layer was washed with brine (30
mL × 2) and dried over Na2SO4. After filtration and removal of the solvent
under reduced pressure, the residue was purified by column
chromatography (hexane/EtOAc = 10:1) on silica gel to give 6-(p-
biphenyl)-3-methylphenanthridine 4A-3 (317.8 mg, 92% yield).
6-(p-Biphenyl)-3-methylphenanthridine (4A-3): Yield: 317.8 mg (92%);
yellow solid; Mp: 164-164 °C; IR (neat) 1482, 1361, 847, 758, 727, 687
cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.61 (s, 3H), 7.40 (t, 1H, J = 7.5 Hz),
7.48-7.55 (m, 3H), 7.62 (t, 1H, J = 7.5 Hz), 7.71 (d, 2H, J = 7.5 Hz), 7.78-
7.88 (m, 5H), 8.10 (s, 1H), 8.19 (d, 1H, J = 8.2 Hz), 8.52 (d, 1H, J = 8.2
Hz), 8.69 (d, 1H, J = 8.2 Hz); 13C{1H}NMR (100 MHz, CDCl3): δ = 21.5,
121.4, 121.7, 122.0, 124.9, 126.6, 127.1 (2C), 127.2 (2C), 127.5, 128.7,
128.8 (2C), 129.8, 130.2 (2C), 130.5, 132.1, 133.5, 138.8, 139.0, 140.8,
141.5, 143.9, 160.8; HRMS (ESI) Calcd for C26H20N [M+H]+ = 346.1590,
Found = 346.1588.
Transformation of 6-(4’-Bromophenyl)-3-methylphenanthridine 3Ah
(IV): To a mixture of 3Ah (348.2 mg, 1.0 mmol), ethynylbenzene (1.5
mmol, 165.0 μL), and CuI (72.0 mg, 0.04 mmol) were added PdCl2(PPh3)2
(280.8 mg, 0.04 mmol), DMF (10.0 mL), and Et3N (2.0 mL) under argon
atmosphere. The obtained mixture was stirred at 60 °C for 6 h. Then,
water (20.0 mL) was added to the reaction mixture, and the product was
extracted with a mixture of hexane and AcOEt ( 4 : 1, 30.0 mL × 3). The
organic layer was washed with brine (30 mL × 2) and dried over Na2SO4.
After filtration and removal of the solvent under reduced pressure, the
residue was purified by column chromatography on silica gel (hexane :
[3] A. Kishi, M. Moriyama, H. Togo, J. Org. Chem., 2018, 83, 11080-
11088, and references are cited therein.
[4] (a) Z. Zhu, M. Zhang, F. Liu, Org. Biomol. Chem. 2019, 17, 1531-
1534. (b) W. Shi, S. Liu, C. Wang, Y. Huang, F. Qing, J. Org. Chem.,
2018, 83, 15236-15244. (c) S. Lu, H. Li, Y. Gong, S. Zhang, J.
Zhang, S. Xu, J. Org. Chem,, 2018, 83, 15415-15425. (d) L. Wang,
W. Xiong, Y. Peng, Q. Ding, Org. Biomol. Chem. 2018, 16, 8837-
8844. (e) J. Li. C. A. D. Caiuby, M. W. Paixao, C. Li, Eur. J. Org.
Chem. 2018, 2498-2503. (f) M. Singh, A. K. Yadav, L. D. S. Yadav,
R. K. P. Singh, Tetrahedron Lett., 2018, 59, 3198-3201. (g) W. Song,
P. Yan, D. Shen, Z. Chen, X. Zeng, G. Zhong, J. Org. Chem., 2017,
82, 4444-4448. (h) Y. Wang, J. Wang, G. Li, G. He, G. Chen, Org.
Lett., 2017, 19, 1442-1445. (i) Q. Yao, X. Zhou, X. Zhang, C. Wang,
P. Wang, M. Li, Org. Biomol. Chem., 2017, 15, 957-971. (j) Z. Xia,
J. Huang, Y. He, J. Zhao, J. Lei, Q. Zhu, Org. Lett. 2014, 16, 2546-
2549.
[5] (a) X. Li, D. Liang, W. Huang, H. Sun, L. Wang, M. Ren, B. Wang,
Y. Ma, Tetrahedron, 2017, 73, 7094-7099. (b) H. Sun, S. Tang, D. Li,
Y. Zhou, J. Huang, Q. Zhu, Org. Biomol. Chem., 2018, 16, 3893-
3896.
[6] (a) W. Guo, Q. Dou, J. Hou, L. Wen, M. Li, J. Org. Chem., 2017, 82,
7015-7022. (b) Z. Wang, T. Li, J. Zhao, X. Shi, D. Jiao, H. Zheng, C.
Chen, B. Zhu, Org. Lett., 2018, 20, 6640-6645. (c) X Liu, R. Mao, C.
Ma, Org. Lett., 2017, 19, 6704-6707. (d) L. Zhang, G. Y. Ang, S.
Chiba, Org. Lett. 2010, 12, 3682-3685. (e) M. Zhu, W. Fu, W. Guo,
Y. Tian, Z. Wang, B. Ji, Org. Biomol. Chem. 2019, 17, 3374-3380.
(f) Y. Bao, Z. Wang, C. Chen, B. Zhu, Y. Wang, J. Zhao, J. Gong, M.
Han, C. Liu, C. Tetrahedron 2019, 75, 1540-1546. (g) Y. Omura, Y.
Tachi, K. Okada, M. Kozaki, J. Org. Chem. 2019, 84, 2032-2038.
[7] (a) C. Tang, Y. Yuan, N. Jiao, Org. Lett., 2015, 17, 2206-2209. (b) X.
An, S. Yu, Org. Lett., 2015, 17, 2692-2695. (c) H. Zhao, Z. Liu, J.
Song, H. Xu, Angew. Chem. Int. Ed., 2017, 56, 12732-12735.
[8] (a) H. Jiang, X. An, K. Tong, T. Zheng, Y. Zhang, S. Yu, Angew.
Chem. Int. Ed., 2015, 54, 4055-4059. (b) H. Zhao, P. Xu, J. Song, H.
Xu, Angew. Chem. Int. Ed., 2018, 57, 15153-15156.
[9] Y. Yuta, K. Morisaki, Y. Hirazawa, H. Morimoto, T. Ohshima,
Development of a Novel Catalytic Direct Synthetic Method of N-
Unprotected Ketimines in Summer Symposium of The Japanese
Society of Process Chemistry (Tokyo), 2018, 90-91.
EtOAc
=
10
:
1)
to
give
3-methyl-6-[(p-
phenylethynyl)phenyl]phenanthridine 4A-4 (344.9 mg, 87% yield).
3-Methyl-6-[(p-phenylethynyl)phenyl]phenanthridine (4A-4): Yield:
321.4 mg (87%); yellow solid; Mp: 132-134 °C; IR (neat) 1359, 1327, 756,
671, 604 cm-1; 1H-NMR (400 MHz, CDCl3): δ = 2.61 (s, 3H), 7.34-7.41 (m,
3H), 7.54 (dd, 1H, J = 8.4, 1.8 Hz), 7.58-7.62 (m, 3H), 7.71-7.77 (m, 4H),
7.85 (td, 1H, J = 7.7, 1.8 Hz), 8.05 (s, 1H), 8.08 (d, 1H, J = 7.7 Hz), 8.51 (d,
1H, J = 8.4 Hz), 8.67 (d, 1H, J = 8.4 Hz); 13C{1H}NMR (100 MHz,
CDCl3): δ = 21.6, 89.2, 90.4, 121.4, 121.7, 122.1, 123.1, 123.6, 124.7,
126.7, 128.4, 128.4 (2C), 128.6, 128.8, 129.8, 129.8 (2C), 130.6, 131.6
(2C), 131.7 (2C), 133.5, 139.1, 139.7, 143.9, 160.4; HRMS (ESI) Calcd for
C28H20N [M+H]+ = 370.1590, Found = 370.1588.
[10] Z. Zhao, B. He, H. Nie, B. Chen, P. Lu, A. Qina, B. Z. Tang, Chem.
Commun., 2014, 50, 1131-1133.
[11] I. Sapountzis, W. Lin, C. C. Kofink, C. Despotopoulou, P. Knochel.,
Angew. Chem. Int. Ed., 2005, 44, 1654 -1657.
[12] F. Zhang, Z. Shi, F. Chen, Y. Yuan, Appl. Organometal. Chem.,
2010, 24, 57-63.
Supporting Information (see footnote on the first page of this article):
Received: ((will be filled in by the editorial staff))
Published online: ((will be filled in by the editorial staff))
Copies of 1H-NMR and 13C-NMR spectra of all aryl o-biaryl ketones 1,
ketimine 2Aa, all 6-arylphenanthridines 3, and their derivatives 4A-1~4A-4.
Submitted to the European Journal of Organic Chemistry
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10.1002/ejoc.201901278
European Journal of Organic Chemistry
Entry for the Table of Contents ((Please choose one layout.))
Layout 1:
(6-Arylphenanthridines)
Aryl biaryl ketones were transformed
into 6-arylphenanthridines efficiently
by the reaction with 1,1,1,3,3,3-
hexamethyldisilazane in the presence of
Sc(OTf)3 in toluene, followed by
removal of the solvent and the
subsequent reaction with molecular
iodine and K2CO3 in a mixture of THF
and methanol.
Eiji Kobayashi, Atsushi Kishi, and
Hideo Togo*… Page No. – Page No.
6-Arylphenanthridines from Aryl o-
Biaryl Ketones with 1,1,1,3,3,3-
Hexamethyldisilazane and Molecular
Iodine
Keywords: 6-Arylphenanthridine /
Ketone / Ketimine / Iodine / Iminyl
Radical
Supporting Information
((Please insert the Supporting Information here))
Submitted to the European Journal of Organic Chemistry
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