[1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium/1, 1′-bis(diphenylphosphino)ferrocene catalyzed synthesis of 2,3-diamino-1,4-naphthoquinones

Article abstract of DOI:10.1055/s-2007-965983

A general method for the synthesis of 2,3-diamino-1,4-naphthoquinone derivatives via the palladium-catalyzed coupling of 2-amino-3-chloro-1,4- naphthoquinones with amines is described. The scope and limitations of the coupling process using [1,1′-bis(diph

Full text of DOI:10.1055/s-2007-965983

PAPER
989
[1,1¢-Bis(diphenylphosphino)ferrocene]dichloropalladium/1,1¢-Bis(diphenyl-
phosphino)ferrocene Catalyzed Synthesis of 2,3-Diamino-1,4-naphtho-
quinones
S
ynthesis of 2,3-D
i
iamino
a
-1,4-naphth
o
oquinones Lei Wang,a Xiu Fang Zheng,a Lei Wang,a John Reiner,*a Wei Lin Xie,b Jun Biao Chang*a,b
a
School of Pharmaceutical Science and Technology, Tianjin University, 300072 Tianjin, P. R. of China
Fax +86(22)27890968; E-mail: jreiner@tju.edu.cn
School of Pharmaceuticals, Xinxiang Medical College, 453003 Xinxiang, P. R. of China
b
Received 5 December 2006; revised 16 January 2007
amine at high temperatures (Scheme 1).11 When 2-
anilino-3-chloro-1,4-naphthoquinone reacted with butyl-
amine in boiling ethanol most of the starting material was
recovered together with a small amount of 2-(butylami-
Abstract: A general method for the synthesis of 2,3-diamino-1,4-
naphthoquinone derivatives via the palladium-catalyzed coupling
of 2-amino-3-chloro-1,4-naphthoquinones with amines is
described. The scope and limitations of the coupling process
using [1,1¢-bis(diphenylphosphino)ferrocene]dichloropalladium no)-3-chloro-1,4-naphthoquinone.10c These drawbacks
[PdCl2(dppf)], combined with 1,1¢-bis(diphenylphosphino)fer-
rocene (dppf) as a ligand and sodium tert-butoxide as base were in-
vestigated, and found to catalyze efficiently the coupling of 2-
(arylamino)-3-chloro-1,4-naphthoquinones with primary aryl- and
alkylamines. A series of novel 2,3-diamino-1,4-naphthoquinone de-
rivatives previously unavailable were obtained by application of
this procedure.
make these methods synthetically unattractive.
O
O
H
N
H
N
NHR1R2
reflux
EWG
R1
Cl
N
R2
EWG
O
O
Key words: catalysis, quinones, aminations, palladium, amines
EWG = SO3H, COOR, I
NHR1R2 = Me2NH, Et2NH, piperidine, morpholine
Mono- and diaminonaphthoquinone structures are impor-
tant in a wide variety of natural products (such as kinamy-
cin, awamycin, and damavaricin)1 and they have been
used as key synthetic intermediates for the construction of
biologically important compounds associated with anti-
trypanosomal,2 antimalarial,3 antitumor,4 and antineo-
plastic5 activities. In most cases, the biological activity is
related to the ability of quinones to accept one or two elec-
trons to form the corresponding radical anion or dianion
species as well the acid–base properties of the com-
pounds. The electron-withdrawing or -donating substitu-
ents at the quinone moiety thus play an important role in
the variable capacity of quinones to accept electrons. In
addition, they have found widespread industrial applica-
tions in color chemistry and hair dying,6 and as photosta-
bilizers.7 Although monoaminonaphthoquinones can be
easily obtained either by the 1,4-addition of amines to 1,4-
naphthoquinone followed by air oxidation8 or by nucleo-
philic addition–elimination reaction of amines with 2-
halo-1,4-naphthoquinone,9 until now there have been no
efficient methods reported for the synthesis of 2,3-diami-
no-1,4-naphthoquinones due to the deactivating effect of
an amino substituent to nucleophilic addition of a second
amino group.10 Successful attempts to introduce a second
amine to 2-amino-3-chloro-1,4-naphthoquinones have
been limited to electron-poor amino-substituted naphtho-
quinones that condensed with an excess of a liquid alkyl-
Scheme
quinones.
1
Literature reported synthesis of diaminonaphtho-
The transition-metal-catalyzed amination of aryl halides
has developed rapidly in the past few years and has proven
to be a powerful method for the synthesis of various sub-
stituted amines.12 Considering the major effect of the use
of palladium complexes in related C–N bond formation
processes discussed in the literature, it seemed reasonable
that the amination of halo-substituted 1,4-naphthoqui-
nones could be performed using a related method. The
coupling of 2,3-dichloro-1,4-naphthoquinone with nitro-
substituted anilines has been applied successfully to the
synthesis of 2-(nitroanilino)-3-chloro-1,4-naphthoqui-
nones, which were difficult to obtain by other methods.9c
In the coupling reactions a trace of the corresponding
symmetric 2,3-bis(nitroanilino)-1,4-naphthoquinone can
also be detected, which informed us of the possibility of
synthesizing asymmetric 2,3-diamino-1,4-naphthoqui-
nones by the amination of 2-amino-3-chloro-1,4-naphtho-
quinones. Herein, we describe a detailed study on the
synthesis of 2,3-diamino-1,4-naphthoquinones by the
coupling of 2-amino-3-chloro-1,4-naphthoquinones with
a series of amines catalyzed by [1,1¢-bis(diphenylphosphi-
no)ferrocene]dichloropalladium/1,1¢-bis(diphenylphosphi-
no)ferrocene [PdCl2(dppf)/dppf] (Scheme 2).
A number of catalyst precursors and ligands (Table 1) that
have been reported to successfully catalyze the amination
of aryl halides were screened in the coupling between 2-
anilino-3-chloro-1,4-naphthoquinone (1) and 4-chloro-
aniline with sodium tert-butoxide as base in refluxing tet-
SYNTHESIS 2007, No. 7, pp 0989–0998
x
x
.
x
x
.2
0
0
7
Advanced online publication: 12.03.2007
DOI: 10.1055/s-2007-965983; Art ID: F19606SS
© Georg Thieme Verlag Stuttgart · New York

990
X. L. Wang et al.
PAPER
actions with a structurally and electronically diverse set of
2-(arylamino)-3-chloro-1,4-naphthoquinones 1–10 and
arylamines under the optimized conditions. The coupling
reaction provides a general route to the corresponding 2,3-
bis(arylamino)-1,4-naphthoquinones 16–29 in good to ex-
cellent yield. 2-Arylamino-3-chloro-1,4-naphthoquinones
with electron-donating groups on the aniline moiety are
less reactive in the coupling reaction as indicated by the
extended reaction time and comparatively lower yields
(Table 2, entries 6, 7). Electron-donating substituents on
the benzenoid moiety of naphthoquinone are similarly de-
activating in the coupling reaction (Table 2, entries 10, 11,
14). The nitro and chloro groups in the benzenoid moiety
of naphthoquinone can also be substituted by the corre-
sponding amines under the coupling conditions; 2,3,5-tri-
anilino-1,4-naphthoquinone (46) has been observed as a
side product (Table 2, entries 9, 13).
O
O
R1
O
O
R1
N
X
X
N
PdCl2(dppf)/dppf
R2
R2
R3
R3NH2
+
t-BuONa, toluene
80 °C or 100 °C
Cl
N
H
X = H, NO2, NH2, Cl, OH
R1, R2, R3 = alkyl or aryl groups
Scheme 2 PdCl2(dppf)/dppf catalyzed coupling of 2-amino-3-chlo-
ro-1,4-naphthoquinones with amines.
rahydrofuran.13 All the catalysts and ligands in Table 1
failed to catalyze the coupling reaction with the exception
of Pd2(dba)3/dppe and PdCl2(dppf)/dppf, the latter gave a
better yield of the coupled product 17. To optimize the re-
action conditions, a variety of solvents such as toluene,
1,4-dioxane, acetonitrile, n-hexane, and N,N-dimethyl-
formamide, and bases such as sodium hydroxide, potassi-
um hydroxide, cesium carbonate, and sodium hydride
were examined together with the stoichiometry of amine,
base, catalyst, and ligand, and the reaction temperature,
for the coupling reaction between 2-anilino-3-chloro-1,4-
naphthoquinone (1) and 4-chloroaniline. The best condi-
tions were found to be those using the amine (1.5 equiv),
sodium tert-butoxide (1.5 equiv) as base, PdCl2(dppf) (5
mol%), and dppf (5 mol%) (relative to 2-anilino-3-chloro-
1,4-naphthoquinone) with toluene as the solvent at
100 °C.
N-Methylaniline and morpholine are inefficient in the
coupling with 2-anilino-3-chloro-1,4-naphthoquinone (1),
which results in the formation of trace amounts only of the
corresponding 2,3-diamino-1,4-naphthoquinones 23 and
38 (experiments not reported) and incomplete reaction
even after extended reaction time (20 h). This may be a
consequence of the steric bulk on the nitrogen atom inhib-
iting the substitution of the tert-butoxy group from the in-
termediate tert-butoxy–palladium complex, which is
necessary for the transamination step.8a Since the
monoamination of 2,3-dichloro-1,4-naphthoquinone with
secondary amines works well, this shortcoming can be
easily overcome by inverting the reaction sequence for the
introduction of the two amines. For example, 2-anilino-3-
(N-methylanilino)-1,4-naphthoquinone (23) was prepared
by the coupling of 2-chloro-3-(N-methylanilino)-1,4-
naphthoquinone (5) with aniline in good yield (Table 2,
entry 8) and 2-anilino-3-morpholino-1,4-naphthoquinone
(38) was prepared by the coupling of 2-chloro-3-mor-
pholino-1,4-naphthoquinone (14) with aniline (Table 3,
entry 10). The inefficiency of the coupling using second-
ary amines may indicate that the steric bulk on the nitro-
gen atom of the amines plays an important role in the
amination reaction.
Table 1 Catalysts, Ligands and Bases Examined for Optimization
of the Coupling Conditionsa
catalyst/
ligand
base
O
O
O
NH2
Cl
H
N
H
N
+
THF, reflux
N
H
Cl
Cl
O
1
17
Entry Catalyst
Ligand
dppf
Base
Yield (%)
b
1
2
3
4
5
6
7
NiCl2(dppf)
NaH/t-BuOH
NaH/t-BuOH
NaH/t-BuOH
t-BuONa
–
b
Ni(acac)2
Ni(OAc)2
Pd(PPh3)4
Pd2(dba)3
Pd2(dba)3
PdCl2(dppf)
IPr·HClc
bipy
–
b
–
Given the success of the PdCl2(dppf)/dppf combination
for the amination of 2-(arylamino)-3-chloro-1,4-naphtho-
quinones with anilines, we were interested in extending
the scope and generality of this method to the coupling of
2-(arylamino)-3-chloro-1,4-naphthoquinones with alkyl-
amines and 2-(alkylamino)-3-chloro-1,4-naphthoqui-
nones with anilines (Table 3). Coupling of 1 with butyl-
amine under the standard conditions [PdCl2(dppf) (5
mol%), dppf (5 mol%), toluene, 100 °C] afforded 2-anili-
no-3-(butylamino)-1,4-naphthoquinone (31) in a moder-
ate 50% yield. The main byproduct observed was 2-
anilino-1,4-naphthoquinone resulting from reduction of
the chloride. Re-evaluating the relative importance of the
amount of PdCl2(dppf)/dppf and the reaction temperature,
the use of 10 mol% PdCl2(dppf) and 10 mol% dppf at
80 °C, resulted in a higher yield of the aminated product
31 (Table 3, entry 2).
b
PPh3
–
b
IPr·HClc
dppe
t-BuONa
–
t-BuONa
60
80
dppf
t-BuONa
a Reaction conditions: 1 (0.7 mmol), p-chloroaniline (1.1 mmol), base
(1.1 mmol), catalyst (0.035 mmol), and ligand (0.035 mmol), THF (5
mL), reflux.
b No desired product detected.
c 1,3-Bis(2,6-diisopropylphenyl)imidazolium chloride.
To investigate the scope of this amination reaction, we
studied the PdCl2(dppf)/dppf catalyzed coupling of differ-
ent 2-(arylamino)-3-chloro-1,4-naphthoquinones with
anilines. Table 2 indicates the results of these coupling re-
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

PAPER
Synthesis of 2,3-Diamino-1,4-naphthoquinones
991
Table 2 Coupling of 2-(Arylamino)-3-chloro-1,4-naphthoquinones with Arylaminesa
Entry Quinone
Amine
Time (h) Product
Yieldb (%)
O
O
H
N
H
N
NH2
1
1
1
2
3
16
17
94
90
N
H
Cl
O
O
O
O
NH2
H
N
H
N
2
N
H
Cl
Cl
Cl
O
O
O
O
H
N
H
N
NH2
Me
3
1
1
2
2
4
2
18
19
20
85
90
83
N
H
Cl
O
O
O
Me
NH2
O
H
N
H
N
4
N
H
NO2
Cl
NO2
NH2
O
O
O
Me
Me
O
H
N
H
N
Me
Me
5
Cl
N
H
OMe
OMe
NH2
O
O
O
O
H
N
H
N
OMe
OEt
OMe
6
3
4
5
6
10
7
21
22
23
75
70
75
Cl
N
H
O
O
O
O
NH2
H
N
H
N
OEt
OEt
7
Cl
N
H
O
O
OEt
NH2
O
O
Me
N
Me
N
8
Cl
N
H
O
O
O
NO2
NO2
NH2
NH2
O
Cl
NO2
N
H
H
N
NH2
9c
6
2
24
80
O
O
N
H
H
N
O
O
Cl
O
O
NH2
NH2
H
N
H
N
NH2
10
7
7
5
6
25
26
65
70
Cl
N
H
O
O
O
O
NH2
Cl
H
N
H
N
11
Cl
N
H
Cl
O
O
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

992
X. L. Wang et al.
PAPER
Table 2 Coupling of 2-(Arylamino)-3-chloro-1,4-naphthoquinones with Arylaminesa (continued)
Entry Quinone
Amine
Time (h) Product
Yieldb (%)
O
O
NH2
NH
O
O
NH
O
O
H
N
8
12
8
27
75
Cl
Cl
N
H
N
H
Cl
Cl
O
Cl
O
H
N
H
N
NH2
13d
14
9
2
28
29
67
27
Cl
N
H
O
O
O
O
OH
OH
OH
OH
H
N
H
N
NH2
10
30
Cl
N
H
O
O
a Reaction conditions: see experimental section.
b Isolated yield.
c 2,3,5-Trianilino-1,4-naphthoquinone (46) was obtained in 10% yield.
d 2,3,5-Trianilino-1,4-naphthoquinone (46) was obtained in 21% yield.
By using a higher catalyst loading and a lower tempera- result is that alkylamines are more electron donating than
ture, a wide range of 2-(alkylamino)-3-(arylamino)-1,4- arylamines and will consequently have a greater deacti-
naphthoquinones 30–40 are available in moderate to good vating effect on the chloro-1,4-naphthoquinone in the cat-
yields. Compared to the coupling between 2-(arylamino)- alyst oxidative addition step. Better yields resulting from
3-chloro-1,4-naphthoquinones and alkylamines, the cou- amination of 2-chloro-3-morpholino-1,4-naphthoquinone
pling of 2-(alkylamino)-3-chloro-1,4-naphthoquinones (14, Table 3, entry 10, 11) may also be attributed to the
with arylamines was found to be less effective (compare lower electron-donating properties of the morpholino
Table 3, entries 2 and 7). A possible explanation for this group.
Table 3 Coupling of 2-(Arylamino)-3-chloro-1,4-naphthoquinones with Alkylamines and Coupling of 2-(Alkylamino)-3-chloro-1,4-naph-
thoquinones with Arylaminesa
Entry Quinone
Amine
Time (h) Product
Yieldb (%)
70
O
O
H
N
NH2
H
N
1
1
1
1
1
30
31
N
H
Cl
O
O
O
O
H
N
H
N
2
75
40
57
NH2
NH2
NH2
N
H
Cl
O
O
O
Me
Me
O
H
N
H
N
Me
Me
O
O
3
2
2
3
32
33
O
Cl
N
H
O
O
O
O
H
N
H
N
NO2
4
11
O
Cl
NO2
N
H
O
O
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

PAPER
Synthesis of 2,3-Diamino-1,4-naphthoquinones
993
Table 3 Coupling of 2-(Arylamino)-3-chloro-1,4-naphthoquinones with Alkylamines and Coupling of 2-(Alkylamino)-3-chloro-1,4-naph-
thoquinones with Arylaminesa (continued)
Entry Quinone
Amine
Time (h) Product
Yieldb (%)
62
O
Me
N
O
Me
N
5
5
6
8
3
34
35
31
NH2
Cl
N
H
O
O
O
NH2
O
NH2
H
N
H
N
6
7
7
42
55
NH2
Cl
N
H
O
O
O
O
H
N
H
N
NH2
NH2
12
Cl
N
H
O
O
O
O
H
N
H
N
8
9
13
13
14
4
6
5
36
37
38
40
45
66
N
H
Me
Cl
Me
O
O
O
O
H
N
NH2
H
N
OMe
N
H
Cl
O
O
O
O
MeO
O
O
O
O
NH2
NH2
N
N
10
Cl
N
H
O
O
O
O
N
N
11
12
14
15
9
6
39
40
70
58
Cl
N
H
OEt
OEt
NH2
O
O
O
O
H
N
H
N
N
H
Cl
O
O
a Reaction conditions: see experimental section.
b Isolated yield.
Finally, coupling of 2-(alkylamino)-3-chloro-1,4-naph- trary to our expectations, the yield of the desired coupling
thoquinones 12–14 with alkylamines afforded lower product diminished and the main product was the dehalo-
yields of 2,3-bis(alkylamino)-1,4-naphthoquinones 41–45 genated product. In such cases, a controlled reaction time
(Table 4). This may be due to two factors: (1) the strong of three hours was used and TLC analysis indicated a bet-
electron-donating effect of the first alkylamino group de- ter ratio of coupled product to dehalogenated byproduct.
activates the chloroquinone and (2) the alkylamine cou- In addition, another possibility for the lower yield of the
pling partner containing a b-hydrogen may promote the coupling reaction using primary alkylamines (Table 3, en-
formation of the dehalogenated byproduct. In the case of tries 1–6 and Table 4) may be due to the formation of cat-
2-(butylamino)-3-chloro-1,4-naphthoquinone (12) ami- alytically inactive bis(amine) complexes, which may also
nations with butylamine and 2-methoxyethylamine (ex- explain the requirement for higher catalyst and ligand
periments not reported) as examples showed a slower loading.14
reaction rate. Extending the reaction time in order to com-
plete the reaction failed to improve the yield, and, con-
naphthoquinones via a palladium-catalyzed coupling
In summary, the synthesis of diverse 2,3-diamino-1,4-
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

994
X. L. Wang et al.
PAPER
Table 4 Coupling of 2-(Alkylamino)-3-chloro-1,4-naphthoquinones with Alkylaminesa
Entry
1
Quinone
Amine
Time (h) Product
Yielda (%)
20
O
O
H
N
H
N
12
13
3
3
41
42
NH2
Cl
N
H
O
O
O
O
H
N
H
N
2
3
4
20
18
65
O
NH2
NH2
O
Cl
N
H
O
O
O
O
H
N
H
N
13
14
3
5
43
44
Cl
N
H
O
O
O
O
O
O
O
O
N
N
NH2
Cl
N
H
O
O
O
O
N
N
5
14
12
45
40
NH2
NH
Cl
O
O
a Reaction conditions: see experimental section.
b Isolated yield.
chromatography (EtOAc–PE, 5:95 to 20:80) to give the correspond-
ing 2,3-bis(arylamino)-1,4-naphthoquinone.
methodology has been developed. The PdCl2(dppf)/dppf
catalyst combined with sodium tert-butoxide proved to be
efficient for the amination of 2-(arylamino)-3-chloro-1,4-
naphthoquinones regardless of the substitution pattern of
the aryl chloride and is applicable to a variety of electron-
rich, electron-poor, and neutral anilines as well as primary
alkylamines. A series of novel, previously unobtainable,
2,3-diamino-1,4-naphthoquinone derivatives were ob-
tained by application of this procedure.
2-(Alkylamino)-3-(arylamino)-1,4-naphthoquinones and 2,3-
Bis(alkylamino)-1,4-naphthoquinones; General Procedure
A mixture of 2-amino-3-chloro-1,4-naphthoquinone (200 mg), t-
BuONa (1.5 equiv), PdCl2(dppf) (10 mol%), dppf (10 mol%), and
the corresponding arylamine (1.5 equiv) in toluene (5 mL) was heat-
ed at 80 °C under N2 in an oven-dried round-bottom flask with mag-
netic stirring. The progress of the reaction was monitored by TLC
(EtOAc–PE). When the reaction was complete, the reaction mixture
was concentrated in vacuo. The crude mixture thus obtained was
purified by chromatography (EtOAc–PE, 2:98 to 20:80) to give the
corresponding 2,3-diamino-1,4-naphthoquinone.
Toluene was distilled from CaH2. t-BuONa, 2,3-dichloro-1,4-naph-
thoquinone, all amines and all other solvents were commercially
available and were used without further purification; dppf,15
PdCl2(dppf),16 NiCl2(dppf),17 dppe,18 IPr·HCl,19 and all the 2-ami-
no-3-chloro-1,4-naphthoquinones20 were prepared according to the
literature. 1H (500 MHz) and 13C NMR (125 MHz) spectra were re-
corded on a Varian Inova 500 MHz. Mps are not corrected. HRMS
were recorded on a Waters Micromass GCT apparatus, or IonSpec
4.7 Tesla FTMS, or Q-TOF micro (Waters) apparatus.
2,3-Dianilino-1,4-naphthoquinone (16)
Dark blue solid; mp 232–233 °C.
1H NMR (500 MHz, DMSO-d6): d = 8.02 (dd, J = 5.5, 3.5 Hz, 2 H),
7.80 (dd, J = 5.5, 3.5 Hz, 2 H), 6.84–6.87 (m, 4 H), 6.64 (t, J = 7.5
Hz, 2 H), 6.38 (d, J = 7.5 Hz, 4 H).
13C NMR (125 MHz, DMSO-d6): d = 181.56, 138.49, 134.36,
131.89, 127.53, 126.35, 124.82, 120.97, 119.94.
HRMS (EI): m/z [M + H]+ calcd for C22H17N2O2: 341.1285; found:
341.1288.
2,3-Bis(arylamino)-1,4-naphthoquinones; General Procedure
A mixture of 2-(arylamino)-3-chloro-1,4-naphthoquinone (200
mg), t-BuONa (1.5 equiv), PdCl2(dppf) (5 mol%), dppf (5 mol%),
and the corresponding arylamine (1.5 equiv) in toluene (5 mL) in an
oven-dried round-bottom flask was heated at 100 °C under N2 with
magnetic stirring. The progress of the reaction was monitored by
TLC (EtOAc–PE). When the reaction was complete, it was concen-
trated in vacuo. The crude mixture thus obtained was purified by
2-Anilino-3-(4-chloroanilino)-1,4-naphthoquinone (17)
Dark blue solid; mp 203–205 °C.
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

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Synthesis of 2,3-Diamino-1,4-naphthoquinones
995
1H NMR (500 MHz, DMSO-d6): d = 8.01–8.03 (m, 2 H), 7.79–7.81
(m, 2 H), 6.85–6.9 (m, 4 H), 6.69 (t, J = 7.5 Hz, 1 H), 6.39 (dd,
J = 7.5, 1.0 Hz, 2 H), 6.34 (dd, J = 6.5, 2.0 Hz, 2 H).
13C NMR (125 MHz, DMSO-d6): d = 181.33, 153.61, 134.17,
131.95, 131.82, 126.20, 124.32, 121.41, 113.80, 63.85, 15.27.
2-Anilino-3-(N-methylanilino)-1,4-naphthoquinone (23)
Dark green solid; mp 163–166 °C.
1H NMR (500 MHz, DMSO-d6): d = 8.05 (dd, J = 8.0, 1.0 Hz, 1 H),
7.94 (dd, J = 7.5, 1.0 Hz, 1 H), 7.85 (td, J = 7.5, 1.5 Hz, 1 H), 7.79
(td, J = 7.5, 1.5 Hz, 1 H), 6.92–7.02 (m, 5 H), 6.79–6.81 (m, 2 H),
6.60 (t, J = 7.5 Hz, 1 H), 6.31 (d, J = 7.5 Hz, 2 H), 2.71 (s, 3 H).
13C NMR (125 MHz, DMSO-d6): d = 181.66, 181.45, 138.16,
137.53, 134.44, 134.33, 131.92, 131.82, 127.55, 127.21, 126.38,
126.37, 125.24, 124.47, 124.14, 121.30, 121.18, 120.22.
2-Anilino-3-(2-methylanilino)-1,4-naphthoquinone (18)
Dark blue solid; mp 206–208 °C.
1H NMR (500 MHz, DMSO-d6): d = 8.03 (t, J = 4.5 Hz, 2 H), 7.81
(t, J = 4.5 Hz, 2 H), 6.86–6.91 (m, 3 H), 6.60–6.66 (m, 3 H), 6.30–
6.39 (m, 3 H), 1.92 (s, 3 H).
13C NMR (125 MHz, DMSO-d6): d = 181.56, 181.49, 138.75,
136.06, 134.55, 134.37, 131.95, 131.69, 129.39, 128.56, 127.62,
126.43, 126.40, 125.43, 125.38, 124.17, 122.38, 120.95, 120.51,
119.43, 18.23.
13C NMR (125 MHz, DMSO-d6): d = 182.93, 180.07, 146.10,
140.17, 139.09, 135.31, 133.42, 133.29, 131.13, 128.86, 127.61,
126.50, 124.67, 124.06, 124.00, 117.58, 113.54, 40.27, 40.10,
39.94, 39.77, 39.60, 37.75.
HRMS (EI): m/z [M + H]+ calcd for C23H19N2O2: 355.1441; found:
355.1449.
2,3-Dianilino-5-nitro-1,4-naphthoquinone (24)
Dark purple solid; mp 238–240 °C.
HRMS (EI): m/z [M + H]+ calcd for C23H19N2O2: 355.1441; found:
355.1447.
1H NMR (500 MHz, CDCl3): d = 8.27 (dd, J = 7.5, 1.0 Hz, 1 H),
7.78 (t, J = 7.5 Hz, 1 H), 7.60 (dd, J = 8.0, 1.5 Hz, 1 H), 7.27 (s, 1
H), 7.19 (s, 1 H), 6.89–6.94 (m, 4 H), 6.75–6.79 (m, 2 H), 6.34 (d,
J = 7.5 Hz, 2 H), 6.30 (d, J = 8.0 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 179.43, 177.62, 148.58, 136.86,
136.81, 134.45, 132.70, 128.58, 127.79, 127.76, 127.15, 123.81,
123.71, 122.71, 122.64, 122.51, 120.74, 120.69.
2-Anilino-3-(4-nitroanilino)-1,4-naphthoquinone (19)
Dark red solid; mp 198–220 °C.
1H NMR (500 MHz, DMSO-d6): d = 8.04–8.09 (m, 2 H), 7.81–7.87
(m, 2 H), 7.74 (d, J = 9.0 Hz, 2 H), 6.91 (t, J = 8.0 Hz, 2 H), 6.79 (t,
J = 7.5 Hz, 1 H), 6.56 (d, J = 7.5 Hz, 2 H), 6.39 (d, J = 7.5 Hz, 2 H).
13C NMR (125 MHz, DMSO-d6): d = 182.21, 180.79, 147.07,
138.77, 137.04, 134.98, 134.05, 132.25, 131.44, 131.28, 127.47,
126.61, 126.42, 124.46, 122.88, 122.28, 119.58, 116.55.
HRMS (EI): m/z [M + H]+ calcd for C22H16N3O4: 386.1135; found:
386.1136.
HRMS (EI): m/z [M + H]+ calcd for C22H16N3O4: 386.1135; found:
386.1145.
5-Amino-2,3-dianilino-1,4-naphthoquinone (25)
Brown solid; mp 192–193 °C.
2-(3,4-Dimethylanilino)-3-(4-methoxyanilino)-1,4-naphtho-
quinone (20)
Dark green solid; mp 185–187 °C.
1H NMR (500 MHz, CDCl3): d = 8.06–8.08 (m, 2 H), 7.63–7.65 (m,
2 H), 7.13 (s, 1 H), 7.07 (s, 1 H), 6.68 (d, J = 7.5 Hz, 1 H), 6.44–6.47
(m, 2 H), 6.24–6.26 (m, 2 H), 6.09–6.11 (m, 2 H), 3.70 (s, 3 H), 2.09
(s, 3 H), 2.03 (s, 3 H).
1H NMR (500 MHz, CDCl3): d = 7.50 (dd, J = 7.5, 1.0 Hz, 1 H),
7.43 (s, 1 H), 7.34 (t, J = 8.0 Hz, 1 H), 7.10 (s, 1 H), 6.85–6.92 (m,
5 H), 6.57–6.75 (m, 4 H), 6.38 (dd, J = 8.5, 1.0 Hz, 2 H), 6.33 (d,
J = 8.5 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 183.38, 181.22, 149.74, 137.79,
137.07, 134.20, 132.47, 127.36, 127.23, 124.63, 123.14, 122.09,
121.73, 121.11, 120.51, 119.73, 117.22, 110.66.
13C NMR (125 MHz, CDCl3): d = 181.64, 181.52, 155.44, 135.62,
135.45, 133.59, 133.49, 131.85, 131.78, 130.84, 130.26, 128.64,
126.36, 124.30, 123.32, 122.35, 122.05, 118.04, 112.84, 55.80,
19.82, 19.24.
HRMS (EI): m/z [M]+ calcd for C22H17N3O2: 355.1321; found:
355.1326.
5-Amino-2-anilino-3-(4-chloroanilino)-1,4-naphthoquinone
(26)
HRMS (EI): m/z [M + H]+ calcd for C25H23N2O3: 399.1703; found:
399.1714.
Brown solid; mp 209–211 °C.
1H NMR (500 MHz, CDCl3): d = 7.51 (dd, J = 7.5, 1.5 Hz, 1 H),
7.46 (s, 1 H), 7.37 (t, J = 8.0 Hz, 1 H), 7.02 (s, 1 H), 6.95 (t, J = 8.0
Hz, 2 H), 6.84–6.89 (m, 3 H), 6.79 (t, J = 7.5 Hz, 1 H), 6.60 (br s, 2
H), 6.40 (d, J = 7.5 Hz, 2 H), 6.23 (d, J = 8.5 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 183.47, 181.31, 150.11, 137.02,
136.71, 134.62, 132.66, 127.62, 127.56, 126.43, 125.26, 123.44,
122.45, 121.85, 121.10, 121.03, 117.57, 110.82.
2-Anilino-3-(4-methoxyanilino)-1,4-naphthoquinone (21)
Dark green solid; mp 190–191 °C.
1H NMR (500 MHz, CDCl3): d = 8.06–8.09 (m, 2 H), 7.62–7.66 (m,
2 H), 7.26 (s, 1 H), 7.14 (s, 1 H), 6.93 (t, J = 8.0 Hz, 2 H), 6.74 (t,
J = 7.5 Hz, 1 H), 6.45–6.48 (m, 2 H), 6.30–6.34 (m, 4 H), 3.68 (s, 3
H).
13C NMR (125 MHz, CDCl3): d = 181.49, 181.11, 155.30, 137.77,
133.50, 133.20, 131.64, 131.38, 130.21, 127.45, 126.18, 126.15,
124.91, 122.26, 122.19, 121.49, 119.78, 112.73, 55.54.
HRMS (EI): m/z [M + H]+ calcd for C23H19N2O3: 371.1390; found:
371.1392.
5-Acetamido-2-anilino-3-(4-chloroanilino)-1,4-naphthoqui-
none (27)
Dark green solid; mp 210–211 °C.
1H NMR (500 MHz, CDCl3): d = 12.03 (s, 1 H), 9.01 (dd, J = 8.5,
1.5 Hz, 1 H), 7.87 (dd, J = 7.5, 1.5 Hz, 1 H), 7.63 (t, J = 8.0 Hz, 1
H), 7.33 (s, 1 H), 7.13 (s, 1 H), 6.95–6.98 (m, 2 H), 6.87–6.89 (m, 2
H), 6.82 (t, J = 7.5 Hz, 1 H), 6.38 (d, J = 7.5 Hz, 2 H), 6.23 (d,
J = 8.5 Hz, 2 H), 2.30 (s, 3 H).
13C NMR (125 MHz, CDCl3): d = 184.86, 181.07, 169.96, 141.48,
136.68, 136.06, 135.20, 131.76, 127.74, 127.70, 127.19, 126.36,
124.10, 122.86, 122.79, 122.27, 121.32, 121.13, 115.17, 25.91.
2,3-Bis(4-ethoxyanilino)-1,4-naphthoquinone (22)
Dark green solid; mp 168–169 °C.
1H NMR (500 MHz, DMSO-d6): d = 7.98 (dd, J = 5.5, 3.5 Hz, 2 H),
7.76 (dd, J = 5.5, 3.0 Hz, 2 H), 6.45 (d, J = 9.0 Hz, 4 H), 6.27 (d,
J = 9.0 Hz, 4 H), 3.86 (q, J = 7.0 Hz, 4 H), 1.25 (t, J = 7.0 Hz, 6 H).
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

996
X. L. Wang et al.
PAPER
2,3-Dianilino-5-chloro-1,4-naphthoquinone (28)
Dark blue solid; mp 180–182 °C.
1H NMR (500 MHz, CDCl3): d = 8.01 (dd, J = 7.5, 1.0 Hz, 2 H),
7.55–7.63 (m, 2 H), 6.96 (d, J = 8.0 Hz, 1 H), 6.56 (d, J = 2.0 Hz, 1
H), 6.47 (dd, J = 8.0, 2.5 Hz, 1 H), 5.91 (s, br, 1 H), 3.25 (s, 3 H),
3.21 (s, 4 H), 2.19 (s, 3 H), 2.16 (s, 3 H).
13C NMR (125 MHz, CDCl3): d = 181.75, 181.11, 140.67, 136.96,
135.59, 133.75, 132.62, 131.92, 131.00, 129.89, 128.70, 126.14,
125.99, 121.39, 118.57, 114.42, 71.51, 58.67, 42.39, 19.96, 18.88.
1H NMR (500 MHz, CDCl3): d = 8.12 (dd, J = 7.5, 1.5 Hz, 1 H),
7.66 (dd, J = 8.0, 1.5 Hz, 1 H), 7.56 (t, J = 8.0 Hz, 1 H), 7.41 (s, 1
H), 7.14 (s, 1 H), 6.90–6.93 (m, 4 H), 6.73–6.78 (m, 2 H), 6.32–6.36
(m, 4 H).
13C NMR (125 MHz, CDCl3): d = 180.14, 180.09, 137.44, 137.29,
137.06, 134.67, 134.37, 133.59, 127.73, 127.64, 127.62, 126.08,
124.87, 122.38, 122.02, 120.79, 120.54, 120.30.
2-(4-Nitroanilino)-3-[(2-methoxyethyl)amino]-1,4-naphtho-
quinone (33)
Dark red solid; mp 162–163 °C.
HRMS (EI): m/z [M + H]+ calcd for C22H16ClN2O2: 375.0895;
found: 375.0893.
1H NMR (500 MHz, CDCl3): d = 8.13 (d, J = 9.0 Hz, 2 H), 8.09 (d,
J = 7.5 Hz, 2 H), 7.72 (t, J = 7.5 Hz, 1 H), 7.64 (t, J = 7.5 Hz, 1 H),
6.74 (s, 1 H), 6.70 (d, J = 9.0 Hz, 2 H), 6.24 (s, 1 H), 3.31–3.37 (m,
7 H).
13C NMR (125 MHz, CDCl3): d = 181.67, 180.46, 150.15, 140.42,
139.60, 134.73, 132.93, 132.05, 130.46, 126.68, 126.42, 125.82,
116.65, 114.68, 71.08, 58.96, 42.68.
2,3-Dianilino-5,8-dihydroxy-1,4-naphthoquinone (29)
Brown solid; mp 241–242 °C.
1H NMR (500 MHz, CDCl3): d = 12.34 (s, 1 H), 7.26 (d, J = 9.0 Hz,
2 H), 7.18 (s, 2 H), 6.92 (t, J = 7.5 Hz, 4 H), 6.77 (t, J = 7.5 Hz, 2
H), 6.35 (d, J = 8.0 Hz, 4 H).
13C NMR (125 MHz, CDCl3): d = 184.14, 157.13, 137.04, 129.19,
127.72, 123.86, 122.43, 120.66, 110.68.
2-(N-Methylanilino)-3-(pentylamino)-1,4-naphthoquinone (34)
Dark red solid; mp 146–148 °C.
2,3,5-Trianilino-1,4-naphthoquinone (46)
Dark green solid; mp 233–234 °C.
1H NMR (500 MHz, CDCl3): d = 8.06 (dt, J = 7.5, 1.5 Hz, 2 H),
7.70 (td, J = 7.5, 1.5 Hz, 1 H), 7.61 (td, J = 7.5, 1.5 Hz, 1 H), 7.18–
7.21 (m, 2 H), 6.69–6.75 (m, 3 H), 5.89 (br s, 1 H), 3.30–3.32 (m, 2
H), 3.19 (s, 3 H), 1.49–1.54 (m, 2 H), 1.20–1.23 (m, 4 H), 0.84 (t,
J = 7.0 Hz, 3 H).
13C NMR (125 MHz, CDCl3): d = 183.19, 180.10, 149.07, 145.29,
134.87, 133.36, 131.99, 130.36, 129.15, 126.48, 126.25, 120.98,
117.51, 112.52, 43.49, 39.63, 29.99, 28.93, 22.25, 13.89.
1H NMR (500 MHz, CDCl3): d = 10.91 (s, 1 H), 7.57 (dd, J = 6.5,
2.5 Hz, 1 H), 7.35–7.43 (m, 5 H), 7.18–7.29 (m, 3 H), 7.13 (s, 1 H),
6.88–6.93 (m, 4 H), 6.70–6.76 (m, 2 H), 6.39 (d, J = 7.5 Hz, 2 H),
6.34 (d, J = 8.0 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 183.75, 181.35, 148.33, 139.60,
137.99, 137.41, 134.59, 132.98, 129.82, 127.66, 127.56, 125.30,
124.82, 124.43, 122.53, 122.04, 121.56, 120.75, 120.35, 120.13,
118.06, 111.49.
HRMS (EI): m/z [M + H]+ calcd for C22H25N2O2: 349.1911; found:
349.1907.
HRMS (EI): m/z [M]+ calcd for C28H21N3O2: 431.1634; found:
431.1631.
5-Amino-2-anilino-3-(butylamino)-1,4-naphthoquinone (35)
Brown solid; mp 102–104 °C.
2-Anilino-3-(benzylamino)-1,4-naphthoquinone (30)
Dark purple solid; mp 156–158 °C.
1H NMR (500 MHz, CDCl3): d = 7.44 (dd, J = 7.5, 1.0 Hz, 1 H),
7.20–7.29 (m, 3 H), 6.82–6.88 (m, 2 H), 6.64–6.74 (m, 3 H), 6.49
(s, br, 2 H), 5.40 (t, J = 6.0 Hz, 1 H), 2.90 (q, J = 7.0 Hz, 2 H), 1.23–
1.29 (m, 2 H), 1.10–1.17 (m, 2 H), 0.74 (t, J = 7.5 Hz, 3 H).
13C NMR (125 MHz, CDCl3): d = 184.01, 182.06, 149.27, 143.02,
135.06, 133.29, 132.09, 128.78, 123.65, 121.17, 120.31, 117.17,
116.92, 111.01, 42.47, 32.52, 19.75, 13.65.
1H NMR (500 MHz, CDCl3): d = 8.01–8.04 (m, 2 H), 7.58–7.66 (m,
2 H), 7.19–7.29 (m, 5 H), 7.01–7.03 (m, 2 H), 6.94 (t, J = 7.5 Hz, 1
H), 6.81 (d, J = 7.5 Hz, 2 H), 6.63 (s, 1 H), 5.85 (t, J = 6.5 Hz, 1 H),
4.08 (d, J = 7.0 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 182.07, 181.53, 142.83, 139.04,
135.63, 134.21, 133.10, 132.06, 131.13, 129.29, 128.83, 128.00,
127.71, 126.54, 126.39, 121.64, 121.09, 117.33, 47.27.
HRMS (EI): m/z [M + H]+ calcd for C20H22N3O2: 336.1707; found:
336.1726.
HRMS (EI): m/z [M + H]+ calcd for C23H19N2O2: 355.1441; found:
355.1431.
2-(Benzylamino)-3-(4-methylanilino)-1,4-naphthoquinone (36)
Dark purple solid; mp 85–87 °C.
2-Anilino-3-(butylamino)-1,4-naphthoquinone (31)
Dark purple solid; mp 85–86 °C.
1H NMR (500 MHz, CDCl3): d = 7.99–8.01 (m, 2 H), 7.55–7.62 (m,
2 H), 7.17–7.22 (m, 3 H), 7.07 (d, J = 8.0 Hz, 2 H), 7.01 (d, J = 8.0
Hz, 2 H), 6.73 (d, J = 8.5 Hz, 2 H), 4.06 (s, 2 H), 2.29 (s, 3 H).
13C NMR (125 MHz, CDCl3): d = 181.70, 181.28, 139.78, 138.92,
134.59, 133.75, 132.80, 131.74, 130.96, 130.34, 129.46, 128.49,
127.70, 127.33, 126.18, 126.06, 122.17, 117.41, 47.07, 20.63.
1H NMR (500 MHz, DMSO-d6): d = 7.98 (dd, J = 7.0, 0.5 Hz, 1 H),
7.95 (dd, J = 7.0, 0.5 Hz, 1 H), 7.80 (td, J = 7.5, 1.5 Hz, 1 H), 7.13
(td, J = 7.5, 1.5 Hz, 1 H), 7.16 (t, J = 9.0 Hz, 2 H), 6.68–6.74 (m, 3
H), 3.12 (t, J = 7.5 Hz, 2 H), 1.34 (quint, J = 7.5 Hz, 2 H), 1.10 (sex-
tet, J = 7.5 Hz, 2 H), 0.73 (t, J = 7.5 Hz, 3 H).
13C NMR (125 MHz, DMSO-d6): d = 182.73, 180.51, 146.44,
141.06, 135.23, 133.27, 132.77, 131.01, 129.38, 126.49, 126.13,
118.83, 117.70, 115.31, 42.64, 32.75, 19.97, 14.18.
HRMS (EI): m/z [M + H]+ calcd for C20H21N2O2: 321.1598; found:
321.1605.
2-(Benzylamino)-3-(2-methoxyanilino)-1,4-naphthoquinone
(37)
Dark purple solid; mp 126–129 °C.
1H NMR (500 MHz, DMSO-d6): d = 7.97 (dd, J = 7.5, 1.5 Hz, 1 H),
7.90 (dd, J = 7.5, 1.5 Hz, 1 H), 7.72–7.80 (m, 2 H), 7.25 (t, J = 7.5
Hz, 2 H), 7.13–7.19 (m, 3 H), 7.01 (dd, J = 6.0, 3.5 Hz, 1 H), 6.82
(dd, J = 6.0, 4.0 Hz, 2 H), 6.42 (dd, J = 6.0, 3.5 Hz, 1 H), 4.13 (s, 2
H), 3.92 (s, 3 H).
2-(3,4-Dimethylanilino)-3-[(2-methoxyethyl)amino]-1,4-naph-
thoquinone (32)
Dark blue solid; mp 108–110 °C.
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

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Synthesis of 2,3-Diamino-1,4-naphthoquinones
997
13C NMR (125 MHz, DMSO-d6): d = 182.23, 180.66, 148.10,
140.47, 139.09, 135.19, 134.10, 133.75, 132.07, 131.04, 128.95,
127.92, 127.64, 126.64, 126.18, 121.34, 120.22, 119.48, 114.46,
111.08, 56.40, 46.01.
HRMS (EI): m/z [M + H]+ calcd for C24H21N2O3: 385.1547; found:
385.1546.
2-(Benzylamino)-3-(butylamino)-1,4-naphthoquinone (43)
Dark purple solid; mp 61–62 °C.
1H NMR (500 MHz, CDCl3): d = 7.93–7.98 (m, 2 H), 7.55–7.58 (m,
2 H), 7.20–7.31 (m, 5 H), 5.07 (s, br, 2 H), 4.30 (s, 2 H), 3.24 (t,
J = 7.5 Hz, 2 H), 1.50–1.56 (m, 2 H), 1.32–1.40 (m, 2 H), 0.90 (m,
3 H).
13C NMR (125 MHz, CDCl3): d = 181.92, 181.54, 139.44, 133.13,
133.05, 132.92, 131.36, 131.28, 131.20, 128.56, 127.58, 127.22,
125.90, 47.07, 43.33, 32.77, 20.11, 13.88.
2-Anilino-3-morpholino-1,4-naphthoquinone (38)
Dark blue solid; mp 106–108 °C.
1H NMR (500 MHz, CDCl3): d = 8.02 (dd, J = 7.5, 1.5 Hz, 2 H),
7.66 (td, J = 7.0, 1.0 Hz, 1 H), 7.61 (td, J = 7.5, 1.0 Hz, 1 H), 7.26–
7.30 (m, 2 H), 7,23 (s, 1 H), 7.04–7.07 (m, 1 H), 6.91 (dd, J = 7.5,
0.5 Hz, 2 H), 3.31 (t, J = 4.5 Hz, 4 H), 3.18 (t, J = 4.5 Hz, 4 H).
13C NMR (125 MHz, CDCl3): d = 182.69, 182.15, 139.05, 134.08,
132.93, 131.93, 131.55, 130.65, 128.53, 126.60, 125.91, 123.34,
121.34, 66.88, 49.01.
2-(Butylamino)-3-morpholino-1,4-naphthoquinone (44)
Dark red solid; mp 108–109 °C.
1H NMR (500 MHz, CDCl3): d = 8.03 (dd, J = 7.5, 1.0 Hz, 1 H),
7.95 (dd, J = 7.5, 1.0 Hz, 1 H), 7.68 (td, J = 7.5, 1.0 Hz, 1 H), 7.55
(td, J = 7.5, 1.0 Hz, 1 H), 6.10 (s, 1 H), 3.83 (q, J = 7.0 Hz, 2 H),
3.76 (t, J = 5.0 Hz, 4 H), 3.23 (s, 4 H), 1.60–1.66 (m, 2 H), 1.41–
1.48 (m, 2 H), 0.98 (t, J = 7.5 Hz, 3 H).
13C NMR (125 MHz, CDCl3): d = 183.84, 181.09, 145.04, 134.50,
133.61, 131.64, 130.32, 125.86, 125.79, 125.71, 67.35, 50.75,
44.93, 32.87, 20.10, 13.87.
HRMS (EI): m/z [M]+ calcd for C20H18N2O3: 334.1317; found:
334.1318.
2-(4-Ethoxyanilino)-3-morpholino-1,4-naphthoquinone (39)
Black solid; mp 125–127 °C.
HRMS (EI): m/z [M]+ calcd for C18H22N2O3: 314.1630; found:
314.1628.
1H NMR (500 MHz, CDCl3): d = 7.98–8.01 (m, 2 H), 7.65 (td,
J = 7.5, 1.0 Hz, 1 H), 7.58 (td, J = 7.5, 1.5 Hz, 1 H), 7.23 (s, 1 H),
6.81–6.87 (m, 4 H), 4.01 (q, J = 7.0 Hz, 2 H), 3.27 (t, J = 5.0 Hz, 4
H), 3.12 (t, J = 5.0 Hz, 4 H), 1.42 (t, J = 7.0 Hz, 3 H).
2-[(2-Methyl-3-phenylpropyl)amino]-3-morpholino-1,4-naph-
thoquinone (45)
Dark oil.
13C NMR (125 MHz, CDCl3): d = 182.65, 181.68, 155.53, 133.92,
133.42, 132.87, 132.39, 131.70, 130.35, 129.91, 126.22, 125.64,
123.24, 114.03, 77.30, 77.05, 76.79, 66.59, 63.76, 48.94, 14.84.
1H NMR (500 MHz, CDCl3): d = 8.03 (dd, J = 8.0, 1.0 Hz, 1 H),
7.97 (dd, J = 7.5, 1.0 Hz, 1 H), 7.68 (td, J = 7.5, 1.0 Hz, 1 H), 7.56
(td, J = 7.5, 1.5 Hz, 1 H), 7.24–7.27 (m, 2 H), 7.14–7.18 (m, 3 H),
5.94 (d, J = 8.5 Hz, 1 H), 4.75–4.80 (m, 1 H), 3.58–3.61 (m, 4 H),
3.15 (br s, 4 H), 2.66–2.78 (m, 2 H), 1.84–1.98 (m, 2 H), 1.25 (d,
J = 6.5 Hz, 3 H).
13C NMR (125 MHz, CDCl3): d = 183.79, 181.29, 144.02, 141.04,
134.55, 133.62, 131.69, 130.23, 128.53, 128.26, 126.11, 125.93,
125.84, 125.25, 67.36, 50.61, 48.57, 39.15, 32.38, 22.32.
2-Anilino-3-(tert-butylamino)-1,4-naphthoquinone (40)
Dark purple solid; mp 119–121 °C.
1H NMR (500 MHz, CDCl3): d = 8.03 (m, 2 H), 7.62–7.65 (m, 2 H),
7.24–7.27 (m, 2 H), 6.94 (t, J = 7.5 Hz, 1 H), 6.81 (d, J = 8.0 Hz, 2
H), 6.76 (s, 1 H), 4.66 (s, 1 H), 1.09 (s, 9 H).
13C NMR (125 MHz, CDCl3): d = 182.97, 182.15, 140.69, 134.57,
133.63, 133.40, 131.85, 131.75, 128.63, 128.00, 126.60, 126.23,
121.69, 119.52, 56.14, 30.55.
Acknowledgment
HRMS (EI): m/z [M]+ calcd for C20H20N2O2: 320.1525; found:
320.1525.
We acknowledge the Tianjin Municipal Science and Technology
Commission (#043186011), the Basic Research Project
(#2002CCA01500) of the MOST. J. B. Chang acknowledges the
Outstanding Scholar Innovation Foundation of Henan Province
(#0521000800), and the New Century Excellent Talent Programme
of the Ministry of Education (#050613) for financial support.
2,3-Bis(butylamino)-1,4-naphthoquinone (41)
Dark purple solid; mp 43–44 °C.
1H NMR (500 MHz, CDCl3): d = 7.97 (dd, J = 5.5, 3.0 Hz, 2 H),
7.57 (dd, J = 5.5, 3.0 Hz, 2 H), 4.82 (s, br, 2 H), 3.13 (t, J = 7.5 Hz,
4 H), 1.47–1.53 (m, 4 H), 1.37 (sextet, J = 7.0 Hz, 4 H), 0.91 (t,
J = 7.5 Hz, 6 H).
References
13C NMR (125 MHz, CDCl3): d = 181.77, 132.94, 132.26, 131.40,
125.83, 43.25, 32.76, 20.12, 13.91.
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Dark purple solid; mp 85–86 °C.
1H NMR (500 MHz, CDCl3): d = 7.93–7.98 (m, 2 H), 7.55–7.58 (m,
2 H), 7.20–7.29 (m, 5 H), 5.28 (s, br, 1 H), 5.19 (br s, 1 H), 4.31 (s,
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125.89, 71.86, 58.89, 47.10, 43.07.
HRMS (EI): m/z [M]+ calcd for C20H20N2O3: 336.1474; found:
336.1473.
Synthesis 2007, No. 7, 989–998 © Thieme Stuttgart · New York

998
X. L. Wang et al.
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