A. Kleineweischede, J. Mattay
FULL PAPER
H, J = 2.5 Hz, H10), 9.33 (d, 1 H, J = 2.5 Hz/1.8 Hz, H6), 9.35 (dd,
7.15 (s, 2 H, H10 and H13), 7.84 (dd, 2 H, J = 8.1 Hz/4.5 Hz, H2
and H7), 9.08 (dd, 2 H, J = 4.5 Hz/1.8 Hz, H3 and H6), 9.44 (dd,
1 H, J = 4.5 Hz/1.8 Hz, H3), 9.63 (dd, 1 H, J = 8.2 Hz/1.8 Hz, H1),
9.67 (dd, 1 H, J = 8.2 Hz/1.8 Hz, H8) ppm. MS (CI, NH3): m/z = 2 H, J = 8.1 Hz/1.8 Hz, H1 and H8) ppm. MS (ESI): m/z = 312
327 [M]+.
[M+].
11,12-Dinitrodipyrido[3,2-a:2Ј,3Ј-c]phenazine (25a): Tan solid, 74%.
1H NMR (CDCl3, 500.1 MHz): δ = 7.89 (dd, 2 H, J = 8.2 Hz/
6-Amino-2,3-bis(2-pyridyl)quinoxaline (17b): Brownish solid, 92%.
1H NMR (CDCl3, 500.1 MHz): δ = 4.53 (s, 2 H, -NH2), 7.03 (dd,
4.4 Hz, H2 and H7), 8.95 (s, 2 H, H10 and H13), 9.38 (d, 2 H, J = 1 H, J = 9.1 Hz/2.2 Hz, H7), 7.07 (d, 1 H, J = 2.2 Hz, H5), 7.13
4.4 Hz, H3 and H6), 9.63 (dd, 2 H, J = 8.2 Hz/1.9 Hz, H1 and H8)
ppm. MS (CI, NH3): m/z = 372 [M]+.
(m, 2 H, H5Ј), 7.71 (m, 2 H, H3Ј), 7.80 (dd, 2 H, H4Ј), 7.86 (d, 1
H, J = 9.1 Hz, H8), 8.37 (dd, 2 H, J = 4.8 Hz/1.8 Hz, H6Ј) ppm.
13C NMR (CDCl3, 125.8 MHz): δ = 107.3 (t, 1C), 122.3 (t, 2C),
122.6 (t, 1C), 123.9 (t, 1C), 124.1 (t, 1C), 129.9 (q, 1C), 135.8 (q,
1C), 136.2 (t, 1C), 136.3 (t, 1C), 142.9 (t, 1C), 148.3 (t, 1C), 148.9
(q, 1C), 151.9 (q, 2C), 157.5 (q, 1C), 157.6 (q, 1C) ppm. MS (CI,
NH3): m/z = 299 [M]+.
11,12-Dimethyldipyrido[3,2-a:2Ј,3Ј-c]phenazine (30a): Light yellow
needles, 95%. 1H NMR (CDCl3, 500.1 MHz): δ = 2.46 (s, 6 H,
-CH3), 7.73 (dd, 2 H, J = 8.2 Hz/4.4 Hz, H2 and H7), 7.95 (s, 2 H,
H10 and H13), 9.21 (dd, 2 H, J = 4.4 Hz/1.9 Hz, H3 and H6), 9.52
(dd, 2 H, J = 8.2 Hz/1.9 Hz, H1 and H8) ppm. 13C NMR (CDCl3,
125.8 MHz): δ = 20.6 (p, 2C, -CH3), 123.9 (q, 2C), 127.7 (t, 2C),
128.1 (q, 2C), 133.4 (q, 2C), 140.2 (t, 2C), 141.5 (t, 2C), 141.7 (q,
2C), 148.1 (t,2C), 152.1 (q, 2C) ppm. MS (CI, NH3): m/z = 310
[M]+.
6,7-Diamino-2,3-bis(2-pyridyl)quinoxaline (20b): Brownish solid,
1
91%. H NMR [D6]DMSO, 500.1 MHz): δ = 5.89 (s, 4 H, -NH2),
6.99 (s, 2 H, H5 and H8), 7.24–7.22 (m, 2 H, J = 6.9 Hz/5.0 Hz/
1.9 Hz, H5Ј), 7.80 (d, 2 H, J = 7.5 Hz, H3Ј), 7.85–7.79 (m, 2 H,
H4Ј), 8.20 (d, 2 H, J = 5.0 Hz, H6Ј) ppm. 13C NMR [D6]DMSO,
125.8 MHz): δ = 104.9 (t, 2C), 121.9 (t, 2C), 123.4 (t, 2C), 136.1
(t, 2C), 137.3 (q, 2C), 142.0 (q, 2C), 146.5 (q, 2C), 147.6 (t, 2C),
158.5 (q, 2C) ppm. MS (CI, NH3): m/z = 314 [M+].
General Procedure for the Synthesis of dpq Derivatives by Schiff
Base Condensation: 2,2Ј-Pyridyl 11b (3.00 mmol) and (3.60 mmol)
of the appropriate o-phenylenediamine derivative were dissolved in
ethanol (100 mL) and heated to reflux for 12 h. The reaction was
cooled to room temperature. Work-up of the reaction mixture is as
follows.
Synthesis of Compound 20a by Reaction of Immobilized Tetraami-
nobenzene with Phendione 11a: To a degassed solution of tetraami-
nobenzene tetrahydrochloride (284 mg, 1.0 mmol) in water (5 mL)
in an argon atmosphere a solution of potassium hydroxide (224
mg, 4.0 mmol) in water (5 mL) was added. The red solution rapidly
turned yellow, and then the cation exchange resin amberlyst 15 was
added (5 g). The solution rapidly became colorless as the amine
joined to the resin. The resin was filtered off, washed with acetoni-
trile (4×50 mL), ether (4×50 mL) and dried under vacuum. This
resin was added to a solution of phendione 11a (210 mg, 1.0 mmol)
in ethanol (20 mL) and was then refluxed for 1 h. The ethanol was
filtered off and the resin treated with a NaOH in methanol solution
(1 , 4×40 mL). The solvent was evaporated under reduced pres-
sure and the product 20a was obtained in ca. 10% yield after col-
umn chromatography on neutral alumina using methanol/dimethyl-
formamide (4:1, v/v) as the eluent.
6-Nitro-2,3-bis(2-pyridyl)quinoxaline (16b): Upon reaction the
product started to precipitate from the solution. The solid was fil-
tered off and dried in vacuo. The product was obtained as golden
crystals in 87% yield. The compound is identical in all aspects to
that reported in ref.[17a]
.
6,7-Dinitro-2,3-bis(2-pyridyl)quinoxaline (25b): The reaction mix-
ture was allowed to stand at room temperature for several days.
Upon slow evaporation of the solvent the product precipitated
from the solution. The product was obtained as red needles in 78%
yield. 1H NMR (CDCl3, 500.1 MHz): δ = 7.34 (ddd, 2 H, H5Ј),
7.94 (td, 2 H, H3Ј), 8.14 (td, 2 H, H4Ј), 8.35 (ddd, 2 H, H6Ј), 8.77
(s, 2 H, H5 and H8) ppm. 13C NMR (CDCl3, 125.8 MHz): δ =
105.2 (t, 2C), 127.3 (t, 2C), 127.4 (t, 2C), 137.2 (t, 2C), 141.3 (q,
2C), 143.4 (q, 2C), 148.4 (t, 2C), 155.6 (q, 2C), 156.5 (q, 2C) ppm.
MS (EI, 70 eV): m/z (%) = 374 (100) [M]+, 282 (61) [M· – 2NO2]+,
281 (79) [M· – NO2 – HNO2]+, 270 (15) [M – C5H4N2]+, 78 (31)
[C5H4N]·, 51 (10).
Synthesis of Diamines 20a and 20b by Detosylation of the Corre-
sponding Tosylated dppz and dpq Derivatives 23a and 23b
4,5-Diamino-N1,N2-ditosyl-o-phenylenediamine (22): 4,5-Dinitro-
N1,N2-ditosyl-o-phenylenediamine (21) (200 mg, 0.39 mmol) and
Pd/C (30 mg, 10%) were suspended in ethanol (100 mL). The re-
sulting mixture was carried out at room temperature for 24 h in a
hydrogen atmosphere (5 bar) in a Parr apparatus. After completion
of the reaction, the catalyst was filtered off and the residue washed
with boiling ethanol. The solvent was evaporated under reduced
pressure. After recrystallization from methanol, product 22 was ob-
General Procedure for the Synthesis of Amino-Substituted dppz (17a,
20a) and dpq Derivatives (17b, 20b) by Reduction of the Correspond-
ing Nitro-Substituted Derivatives: The nitro-substituted heterocycle
16a or 16b or dinitro-substituted heterocycle 25a or 25b (150 mg)
and Pd/C (15 mg, 10%) were suspended in ethanol (100 mL). The
resulting mixture was carried out at room temperature for 24 h in
a hydrogen atmosphere (5 bar) in a Parr apparatus. After comple-
tion of the reaction, the catalyst was filtered off and the residue
washed with boiling ethanol. The solvent was evaporated under
reduced pressure.
tained as
a
white solid in 91% yield. 1H NMR (CDCl3,
500.1 MHz): δ = 2.43 (s, 6 H, -CH3), 6.52 (s, 2 H, H3 and H6), 7.27
(m, 2 H, H2Ј and H6Ј), 7.72 (m, 2 H, H3Ј and H5Ј) ppm. MS (EI):
m/z (%) = 446 (17) [M]+, 276 (100) [M· – C7H7SO2]+.
11-Aminodipyrido[3,2-a:2Ј,3Ј-c]phenazine (17a): Orange-red solid,
89%. 1H NMR [D6]DMSO, 500.1 MHz): δ = 7.24 (d, 1 H, J =
9.2 Hz, H10), 7.95 (dd, 1 H, J = 8.0 Hz/4.3 Hz, H7), 8.01 (dd, 1 H,
J = 8.0 Hz/4.3 Hz, H2), 8.14 (d, 1 H, J = 2.1 Hz, H13), 9.18 (dd, 1
H, J = 4.3 Hz/1.4 Hz, H3), 9.25 (dd, 1 H, J = 4.3 Hz/1.4 Hz, H6),
9.51 (dd, 1 H, J = 8.0 Hz/1.3 Hz, H1), 9.57 (dd, 1 H, J = 8.0 Hz/
1.3 Hz, H8) ppm. MS (CI, NH3): m/z = 297 [M]+.
General Procedure for the Synthesis of the Tosylated Diamines 23a
and 23b by Condensation of Compound 22 with the Diketones 11a
and 11b: 4,5-Diamino-N1,N2-ditosyl-o-phenylenediamine (22) (1.34
g, 3.00 mmol) and the corresponding diketone 11a or 11b (2.50
mmol) were suspended in methanol (30 mL) and heated to reflux
resulting in a clear solution. To complete the reaction, heating of
the reaction mixture was continued for further 60 min. In the case
of the dppz derivative the product started to precipitate after a
short period of time. The hot solution was filtered and the crude
11,12-Diaminodipyrido[3,2-a:2Ј,3Ј-c]phenazine (20a): Brown solid,
1
93%. H NMR [D6]DMSO, 500.1 MHz): δ = 6.27 (s, 4 H, NH2),
954
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Eur. J. Org. Chem. 2006, 947–957