A simple route to 2-aryl-substituted naphtho[2,1-e][1,2,4]triazinium and naphtho[2,1-e][1,2,3,4]tetrazinium salts from 1-arylazo-substituted 2-naphthylamines

Article abstract of DOI:10.1515/znb-2018-0003

1-Arylazo-substituted 2-naphthylamines, which are easily obtainable by the coupling of arene diazonium salts with 2-aminonaphthalene-sulfonic acid, can be transformed by reaction with reactive carboxylic acid derivatives or nitrosation reagents into novel 2-aryl-substituted naphtho[2,1-e][1,2,4]triazinium and naphtho[2,1-e][1,2,3,4]tetrazinium salts, respectively.

Full text of DOI:10.1515/znb-2018-0003

Z. Naturforsch. 2018; 73(7)b: 431–435
Xiuling Yu, Peter Metz and Horst Hartmann*
A simple route to 2-aryl-substituted naphtho[2,1-e][1,2,4]-
triazinium and naphtho[2,1-e][1,2,3,4]tetrazinium salts from
1-arylazo-substituted 2-naphthylamines
https://doi.org/10.1515/znb-2018-0003
Received January 4, 2018; accepted February 19, 2018
of the results obtained are reported in the following and
depicted in Scheme 2.
Abstract: 1-Arylazo-substituted 2-naphthylamines, which
are easily obtainable by the coupling of arene diazo-
nium salts with 2-aminonaphthalene-sulfonic acid, can 2 Results and discussion
be transformed by reaction with reactive carboxylic acid
derivatives or nitrosation reagents into novel 2-aryl-sub- Besides the transformation of 1-arylazo-2-naphthylamines
stituted naphtho[2,1-e][1,2,4]triazinium and naphtho[2,1-e] 8 into the corresponding naphtho[1,2,3]triazoles, which
[1,2,3,4]tetrazinium salts, respectively.
was studied earlier by other authors [7], the reaction of
azo compounds 8 with certain reactive carboxylic acid
derivatives, such as the Vilsmeier reagent or carbox-
ylic acid anhydrides, has been studied. Thereby, novel
naphtho[1,2,4]triazinium salts 9 and 10 are formed in
mostly satisfactory yields.
Keywords: 2-naphthylamine-1-azo compounds; acylation;
naphtho[2,1-e][1,2,3,4]tetrazinium salts; naphtho[2,1-e]-
[1,2,4]triazinium salts; nitrosation.
Furthermore, the 1-arylazo-2-naphthylamines 8 are
able to react with certain nitrosation reagents, such as
nitrosyl sulfuric acid, yielding the corresponding diazo-
1 Introduction
2-Amino azoarenes 3, which are obtainable by the cou- nium salts 11. These salts exist, however, as confirmed by
1
pling of a 4-substituted aniline 1 with an arene diazonium IR and H NMR measurements, in a valence tautomeric
salt 2 [1], are interesting starting materials for the synthesis naphtha[1,2,3,4]tetrazinium structure 13 and are there-
of certain heterocyclic systems. Thus, these compounds 3 fore not able to couple with reactive aromatic compounds
can be transformed by oxidation into benzo[1,2,3]triazines C6H5X, such as N,N-dialkylanilines (X=NR2) or phenols
4 [2] or by reaction with nitrosation reagents NOX into (X=OH), to give the corresponding bis-azo compounds 12.
rather unstable diazonium salts 5, which give rise by their Instead of coupling, the naphtho[1,2,3,4]tetrazinium salts
reaction with special nucleophiles to 1-imino-benzo[1,2,3] 13 decompose by standing, and yield, e.g. in methanolic
triazolium ylides 6 [3]. As coupling of the anilines 1 with solution, the corresponding 2-methoxy-1-arylazonaphtha-
the arene diazonium salts 2 gives rise usually to low yields lenes 14.
of products [4, 5], the heterocyclic compounds 4 and 6
The structures of the compounds prepared were con-
1
prepared this way from 3 have been documented only in a firmed by mass spectrometry and H NMR spectroscopy.
few examples (Scheme 1).
Thus, in the mass spectra of compounds 10, the expected
Since the 1-arylazo-2-naphthylamines 8 are, as benzo- molecular ions were detected. In the mass spectra of the
condensed 2-amino-substituted azoarenes, much more salts 13, besides the molecular ion peaks, further peaks
easily available, e.g. by the coupling of 2-naphtylamine- were observed, indicating a loss of N2. In the mass spectra
1-sulfonic acid 7 with arenediazonium salts 2 [6], their of some of the salts 9, adduct peaks with methanol could
use as starting materials for the synthesis of heterocy- be detected next to those of the corresponding molecular
clic compounds was studied by us in more detail. Some ions. Obviously, the methanol peaks stemmed from the
solvent used for measuring the mass spectra and was
added to the corresponding salt peaks during the meas-
1
*Corresponding author: Horst Hartmann, Lehrstuhl Organische
Chemie I, Fakultät Chemie und Lebensmittelchemie, Technische
Universität Dresden, D-01062 Dresden, Germany,
Fax: 0049 351 4633 9485, E-mail: Horst.Hartmann@tu-dresden.de
Xiuling Yu and Peter Metz: Lehrstuhl Organische Chemie I, Fakultät
Chemie und Lebensmittelchemie, Technische Universität Dresden,
D-01062 Dresden, Germany
urement. In the H NMR spectra of the salts 9 and 10,
characteristic signals for the protons at the 1,2,3-triazine
rings at about 10.0 ppm and for the methyl group at about
3.0 ppm, respectively, were found.
To exclude diazonium salts 11 as the products
obtained by the diazotation of compounds 8, IR spectra
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ꢀX. Yu et al.: Preparation of 2-aryl-substituted naphtho[2,1-e][1,2,4]triazinium
R4
N
N
Ar
N
Ox.
Ar
4
N
N
R4
R4
Ar
Ar
N
+
N
N
R4
R4
N
NH2
NH2
NOX
N
N
+ Y−
3
2
N
Ar
1
X−
N
N
N
5
Y
6
Scheme 1:ꢀReported use of 2-aminoazobenzenes 3 for the preparation of heterocyclic compounds.
X
X
X
X
N
N
N
N
+
NO+HSO4
(HClO4)
−
SO3H
NH2
N
N
N
ClO4
N
N
N
NH2
N
N
8
13
7
11
2
RC(=Y)Z
(HClO4)
CH3OH
– N2
C6H5X
X
X
X
X
X
2, 8–14
N
N
N
N
R
N
N
a
b
c
d
CH3
CH3O
Cl
N
N
ClO4
N
OCH3
14
12
NO2
9: R = H, Y = NMe2+, Z = Cl
10: R = Me, Y = O, Z = CH3COO
Scheme 2:ꢀSynthetic route to 1-arylazo-2-naphthylamines 8 and their transformation into new 2-aryl-substituted naphtho[2,1-e][1,2,4]
triazinium salts 9 and 10, and naphtha[1,2-e][1,2,3,4]tetrazinium salts 13.
of these compounds were recorded. In no case, bands in 3.1 Preparation of 1-arylazo-substituted
the region 2250–2300 cm−1, which are characteristic for
2-napthylamines 8 (general procedure)
⊕
the −N ≡ N moiety, were found. Therefore, the products
obtained by this reaction exist exclusively in their hetero-
cyclic 1,2,3,4-tetrazinium form 13.
To an aromatic or heteroaromatic amine (10 mmol) dis-
solved in aqueous hydrochloric acid (15 mL, 50%), sodium
nitrite (0.84 g, 8 mmol) was added in small portions at
0°C. After 30 min, urea (1 g) was added, and the result-
ing mixture was poured into an aqueous/methanolic
solution (1:1, 50 mL) of 2-aminonaphthalene sulfonic acid
(2.2 g, 10 mmol). The product precipitated was isolated
by suction, washed with water, and recrystallized from
butanol after drying.
3 Experimental section
1H NMR spectra were recorded with a Bruker DRX 500
P instrument at 500.13 MHz; chemical shifts δ are given
in ppm and coupling constants (J) in Hz. UV/vis spectra
were measured in dichloromethane with a Perkin Elmer
Lambda 900 UV/vis/NIR spectrometer, and mass spectra
The following 1-arylazo substituted 2-naphthylamines
8 were prepared by the above procedure:
were recorded with a Bruker Esquire MS (ESI) or with 3.1.1 1-(4-Tolylazo)-2-naphthylamin (8a)
a MAT 8200 Finnigan spectrometer (HRMS). Melting
points were measured with a Boetius heating-table This compound was prepared from 2-amino-naphthaline-
microscope.
1-sulfonic acid (7) and 4-toluene diazonium hydrosulfate
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ꢂ433
(2a) as an orange crystalline powder; yield 80%, m.p.
3.2 Preparation of 2-aryl-substituted
1
111°C. UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ436 nm (4.34). H
naphtho[2,1-e][1,2,4]triazinium
NMR ([D6]DMSO): δꢀ=ꢀ3.84 (s, 3H, CH3), 7.10 (m, 2 arom.
H), 7.29 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H), 7.50 (d, Jꢀ=ꢀ8.0 Hz, 1
perchlorates (9) (general procedure)
arom. H), 7.82 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 7.92 (d, Jꢀ=ꢀ8.0 Hz, 2 To a solution of a 1-arylazo substituted 2-napthylamine
arom. H), 8.72 (d, Jꢀ=ꢀ7.5 Hz, 2 arom. H), 8.05 (d, Jꢀ=ꢀ9.5 Hz, 8 (10 mmol) in DMF (20 mL), phosphoryl chloride (5 mL)
1 arom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ262.0 (calcd. 262.13 was added with cooling at ~0°C. After allowing it to
+
for [C17H16N3] ).
stand for some time, methanol (15 mL) was added, fol-
lowed by perchloric acid (5 mL, 70%) and diethyl ether
(50 mL). The precipitate formed was isolated by suction,
dried under air, and recrystallized from acetic acid/ethyl
acetate.
3.1.2 1-(4-Methoxyphenylazo)-2-naphthylamin (8b)
The following 3-aryl-substituted naphtho[1,2,4]-
triazinium perchlorates (9) were prepared by the above
procedure.
It was prepared from 2-amino-naphthaline-1-sulfonic acid
(7) and 4-methoxybenzene diazonium hydrosulfate (2b)
as an orange crystalline powder; yield 93%, m.p. 126°C.
1
UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ451 nm (4.37). H NMR ([D6]
DMSO): δꢀ=ꢀ2.26 (s, 3H, CH3), 6.84 (d, Jꢀ=ꢀ10.0 Hz, 1 arom. 3.2.1 2-(p-Tolyl)naphtho[2,1-e][1,2,4]triazinium
H), 7.19 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 7.36 (d, Jꢀ=ꢀ9.0 Hz, 2 arom.
H), 7.44 (t, Jꢀ=ꢀ7.0 Hz, 1 arom. H), 7.60 (t, Jꢀ=ꢀ8.0 Hz, 1 arom.
perchlorate (9a)
H), 7.72 (d, Jꢀ=ꢀ10.0 Hz, 1 arom. H), 8.05 (d, Jꢀ=ꢀ8.0 Hz, It was prepared from 1-(4-tolylazo)-2-naphthylamine
1 arom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ278.1 (calcd. 278.13 for (8a) as an orange crystalline powder; yield 65%, m.p.
+
[C17H16N3O] ).
252–254°C. UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ459 nm (4.18).
1H NMR (TFA): δꢀ=ꢀ2.49 (s, 3H, CH3), 7.56 (d, Jꢀ=ꢀ8.0 Hz, 2
arom. H), 7.93 (d, Jꢀ=ꢀ8.0 Hz, 2 arom. H), 8.08–8.13 (m, 3
arom. H), 8.21 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H), 8.84 (d, Jꢀ=ꢀ8.0 Hz,
1 arom. H), 9.28 (t, Jꢀ=ꢀ8.0 Hz, 1 arom. H), 10.33 (s, 1 arom.
H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ304.1 (calcd. 304.37 for
3.1.3 1-(4-Chlorphenylazo)-2-naphthylamin (8c)
It was prepared from 2-amino-naphthaline-1-sulfonic acid
(7) and 4-chlorobenzene diazonium hydrosulfate (2c) as a
brown crystalline powder; yield 77%, m.p. 112°C. UV/vis
(CH2Cl2): λmax (log ε):ꢀ=ꢀ457 nm (4.28). 1H NMR ([D6]DMSO):
δꢀ=ꢀ7.15 (d, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 7.33 (m, 1 arom. H), 7.51–
7.56 (m, 1 arom. H), 7.62 (d, Jꢀ=ꢀ8.0 Hz, 2 arom. H), 7.73–7.80
(d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 7.98 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 8.72
(d, Jꢀ=ꢀ9.0 Hz, 1 arom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ282.1
+
[C18H14N3ꢀ+ꢀCH3OH] ).
3.2.2 2-(4-Methoxyphenyl)naphtho[2,1-e][1,2,4]-
triazinium perchlorate (9b)
It was prepared from 1-(4-methoxyphenylazo)-2-naphthyl-
amine (8b) as an orange crystalline powder; yield 66%,
m.p. 178–180°C. UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ484 nm
+
(calcd. 282.74 for [C16H13ClN3] ).
1
(4.16). H NMR (TFA): δꢀ=ꢀ3.95 (s, 3H, OCH3), 7.26 (d,
Jꢀ=ꢀ15.0 Hz, 2 arom. H), 8.04–8.18 (m, 6 arom. H), 8.78 (d,
Jꢀ=ꢀ15 Hz, 1 arom. H), 9.25–9.27 (m, 1 arom. H), 10.31 (s,
3.1.4 1-(4-Nitrophenyl-2-ylazo)-2-naphthylamin (8d)
1 hetarom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ288.1 (calcd. 288.11
+
It was prepared from 2-amino-naphthaline-1-sulfonic for [C18H14N3O] ).
acid (7) and 4-nitrobenzene diazonium hydrosulfate (2d)
as a red crystalline powder; yield 95%, m.p. 185–187°C.
UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ503 nm (4.47). 1H NMR ([D6] 3.2.3 2-(4-Chloropheny)naphtho[2,1-e][1,2,4]triazinium
DMSO): δꢀ=ꢀ7.16 (d, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 7.35 (m, 1 arom.
H), 7.56 (m, 1 arom. H), 7.74 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H),
perchlorate (9c)
7.82 (s, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 8.12 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. It was prepared from 1-(4-chlorophenylazo)-2-naphth-
H), 8.36 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 8.71 (d, Jꢀ=ꢀ8.0 Hz, 1 ylamine (8c) as a brown crystalline powder; yield 74%,
arom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ293.1 (calcd. 293.10 for m.p. 158–160°C. UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ456 nm
+
1
[C13H11N4S] ).
(4.00). H NMR (TFA): δꢀ=ꢀ7.68 (d, Jꢀ=ꢀ10.0 Hz, 2 arom.
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H), 7.98 (d, Jꢀ=ꢀ10 Hz, 2 arom. H), 8.05–8.10 (m, 3 arom. 3.3.2 2-(4-Methoxyphenyl)-3-methylnaphtho[2,1-e]-
H), 8.16 (d, Jꢀ=ꢀ10.0 Hz, 1 arom. H), 8.81 (d, Jꢀ=ꢀ10.0 Hz, 1
arom. H), 9.23 (d, Jꢀ=ꢀ5.0 Hz, 1 arom. H), 10.31 (s, hetarom.
[1,2,4]triazinium perchlorate (10b)
H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ324.2 (calcd. 324.09 for It was prepared from 1-(4-methoxyphenylazo)-2-naphth-
+
[C17H11ClN3ꢀ+ꢀCH3OH] ).
ylamine (8b) as a yellow crystalline powder; yield 86%,
m.p. 229°C (dec.). UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ439 nm
1
(4.00). H NMR (CDCl3): δꢀ=ꢀ3.22 (s, 3H, CH3), 4.09 (s, 3H,
CH3O), 7.38 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 7.76 (d, Jꢀ=ꢀ9.0 Hz, 2
arom. H), 8.08–8.16 (m, 3 arom. H), 8.23 (d, Jꢀ=ꢀ8.0 Hz, 1
arom. H), 8.86 (d, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 9.18 (d, Jꢀ=ꢀ8.0 Hz,
1 arom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ302.1 (calcd. 302.13 for
3.2.4 2-(4-Nitrophenyl)naphtho[2,1-e][1,2,4]triazinium
perchlorate (9d)
It was prepared from 1-(4-nitrophenylazo)-2-naphthyl-
amine (8d) as a brown crystalline powder; yield 32%,
m.p.ꢀ=ꢀ176–180°C. UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ452 nm
+
[C19H16N3O] ).
1
(4.00). H NMR (TFA): δꢀ=ꢀ8.14–8.23 (m, 3 arom. H), 8.26
3.3.3 2-(4-Chlorophenyl)-3-methylnaphtho[2,1-e][1,2,4]-
(d, Jꢀ=ꢀ6.0 Hz, 1 arom. H), 8.37 (d, Jꢀ=ꢀ13 Hz, 2 arom. H),
8.63 (d, Jꢀ=ꢀ14 Hz, 2 arom. H), 8.93 (d, Jꢀ=ꢀ15 Hz, 1 arom.
H), 9.28 (d, Jꢀ=ꢀ8 Hz, 1 arom. H), 10.51 (s, 1 hetarom.
H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ335.1 (calcd. 335.11 for
triazinium perchlorate (10c)
It was prepared from 1-(4-chlorophenylazo)-2-naphthyl-
amine (8c) as a yellow crystalline powder; yield 88%, m.p.
214°C (dec.). UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ432 nm (3.86).
1H NMR (CDCl3): δꢀ=ꢀ3.06 (s, 3H, CH3), 7.61 (d, Jꢀ=ꢀ9.0 Hz, 2
arom. H), 7.66 (d, Jꢀ=ꢀ8.0 Hz, 2 arom. H), 7.94–8.03 (m, 3
arom. H), 8.10 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H), 8.74 (d, Jꢀ=ꢀ9.0 Hz,
1 arom. H), 9.02 (d Jꢀ=ꢀ8.0 Hz, 1 arom. H) ppm. MS ((+)-ESI):
+
[C14H9N4Sꢀ+ꢀCH3OH] ).
3.3 Preparation of 2-aryl-substituted
3-methylnaphtho[2,1-e][1,2,4]triazinium
salts (10) (general procedure)
+
m/zꢀ=ꢀ338.2, (calcd. 338.11 for [C18H13ClN3ꢀ+ꢀCH3OH] ).
To a solution of a 1-arylazo-substituted 2-napthylamine 8
(10 mmol) in acetic anhydride (15 mL), magnesium per- 3.3.4 3-Methyl-2-(4-nitrophenyl)naphtho[2,1-e][1,2,4]-
chlorate (3 g) was added with cooling. After allowing it to
stand for some time, the mixture was heated at 100°C until
triazinium perchlorate (10d)
a clear solution was obtained. Following cooling down to It was prepared from 1-(4-nitrophenylazo)-2-naphthyl-
room temperature, ethyl acetate (50 mL) was added, and amine (8d) as a brown crystalline powder; yield 50%, m.p.
the product precipitated was isolated by suction, dried, 227–229°C (dec.). UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ438 nm
and recrystallized from acetic acid.
(3.82). 1H NMR (CDCl3): δꢀ=ꢀ3.08 (s, 3H, CH3), 7.96 (t, 1 arom.
The following 3-(het)aryl-substituted 3-methyl- H), 8.00–8.04 (m, 4 arom. H), 8.12 (d, Jꢀ=ꢀ8.0 Hz, 1 arom.
naphtho[2,1-e][1,2,4]triazinium perchlorates (10) were H), 8.59 (d, Jꢀ=ꢀ8.5 Hz, 2 arom. H), 8.78 (d, Jꢀ=ꢀ9.0 Hz, 1
prepared by this procedure:
arom. H), 9.00 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H) ppm. MS ((+)-ESI):
+
m/zꢀ=ꢀ349.2 (calcd. 349,13 for [C15H11N4Sꢀ+ꢀCH3OH] ).
3.3.1 3-Methyl-2-(p-tolyl)naphtho[2,1-e][1,2,4]triazinium
perchlorate (10a)
3.4 Preparation of 2-aryl-substituted
naphtho[1,2-e][1,2,3,4]-tetrazinium salts
(13) (general procedure)
It was prepared from 1-(4-tolylazo)-2-naphthylamine (8a)
as a yellow crystalline powder; yield 71%, m.p. 245°C
(dec.). UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ431 nm (3.94). 1H NMR To a solution of a 1-arylazo-substituted 2-napthylamine
(TFA): δꢀ=ꢀ2.46 (s, 3H, CH3), 3.06 (S, 3H, CH3), 7.48–7.52 (m, 8 (10 mmol) in ethyl acetate (50 mL) containing magne-
4 arom. H), 7.93–7.96 (m, 1 arom. H), 8.0 (d. Jꢀ=ꢀ8.0 Hz, 2 sium perchlorate (3 g), isoamyl nitrite (2.3 g, 20 mmol) was
arom. H), 8.72 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H9), 9.04 (d, Jꢀ=ꢀ8.0 Hz, added at 0°C. Subsequently, after some time, perchloric
1 arom. H) ppm. MS ((+)-ESI): m/zꢀ=ꢀ286.1 (calcd. 286.13 for acid (5 mL, 70%) was added to the reaction mixture at
+
[C19H16N3] ).
0°C. After warming the mixture to room temperature, the
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ꢂ435
product precipitated, which was isolated by suction and 3.4.4 2-(4-Nitrophenyl)naphtho[1,2-e][1,2,3,4]-
recrystallized after drying.
tetrazinium perchlorate (13d)
The following 2-(het)aryl-substituted naphtho[1,2-e]
[1,2,3,4]tetrazinium perchlorates were prepared by the It was prepared from 1-(4-nitrophenylazo)-2-naphth-
above procedure:
ylamine (8d) as a red solid; yield 54%, m.p. 173°C.
UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ494 nm (3.91). 1H NMR (TFA):
δꢀ=ꢀ8.09–8.19 (m, 2 arom. H), 8.25–8.33 (m, 1 arom. H),
8.41 (d, Jꢀ=ꢀ15 Hz, 1 arom. H), 8.55 (s, 4 arom. H), 8.68 (d,
Jꢀ=ꢀ14 Hz, 1 arom. H), 9.28 (d, Jꢀ=ꢀ8 Hz, 1 arom. H) ppm.
3.4.1 2-(p-Tolyl)naphtho[1,2-e][1,2,3,4]tetrazinium
perchlorate (13a)
HRMS ((+)-ESI): m/zꢀ=ꢀ304.0833 (calcd. 304.0834 for
+
It was prepared from 1-(p-tolylazo)-2-naphtylamine (8a) [C16H10N5O2] ).
as a red solid; yield 56%, m.p. 189–190°C (dec.). UV/vis
(CH2Cl2): λmax (log ε):ꢀ=ꢀ502 nm (4.35). H NMR (CDCl3):
1
δꢀ=ꢀ2.50 (s, 3H, CH3), 7.55 (d, Jꢀ=ꢀ8.5 Hz, 2 arom. H), 8.16– 3.4.5 2-Methoxy-1-(4-tolylazo)naphthalene 14a (R=Me)
8.26 (m, 2 arom. H), 8.43 (d, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 8.49 (d,
Jꢀ=ꢀ8.5 Hz, 2 arom. H), 8.91 (d, Jꢀ=ꢀ7.0 Hz, 1 arom. H), 9.41 (d, It was prepared by letting a methanolic solution of
Jꢀ=ꢀ8.0 Hz, 1 arom. H) ppm. HRMS ((+)-ESI): m/zꢀ=ꢀ273.1138 2-(tolyl)naphtho[1,2-e][1,2,3,4]tetrazinium
perchlorate
+
(calcd. 273.1140 for [C17H13N4H] ).
(13a) stand for 3 days at room temperature and by adding
water. The product precipitated was isolated by filtration
in a yield of 68%. After drying under air and recrystalli-
zation, an orange solid with a melting point of 63°C (Lit.
[8]: m.p. 61–63°C) was obtained. 1H NMR (CDCl3): δꢀ=ꢀ2.50
(s, 3H, CH3), 4.46 (s, 3H, OCH3), 7.41 (d, Jꢀ=ꢀ5.0 Hz, 2 arom.
3.4.2 2-(4-Methoxyphenyl)naphtho[1,2-e][1,2,3,4]-
tetrazinium perchlorate (13b)
It was prepared from 1-(4-methoxyphenylazo)-2-naph- H), 7.46 (d, Jꢀ=ꢀ8.0 Hz, 1 arom. H), 7.60 (t, Jꢀ=ꢀ7.0 Hz, 1 arom.
tylamine (8b) as a red solid; yield 64%, m.p. 178–180°C H), 7.84 (t, Jꢀ=ꢀ7.0 Hz, 1 arom. H), 7.84–7.86 (m, 3 arom.
(dec.). UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ535 nm (4.22).1H NMR H), 8.40 (d, Jꢀ=ꢀ10.0 Hz, 1 arom. H), 8.70 (d, Jꢀ=ꢀ10.0 Hz,
(TFA): δꢀ=ꢀ4.00 (s, 3H, OCH3), 7.24 (d, Jꢀ=ꢀ15 Hz, 2 arom. H), 1 arom. H). MS ((+)-ESI): m/zꢀ=ꢀ277.2 (calcd. 277.13 for
+
8.11–8.27 (m, 3 arom. H), 8.32 (d, Jꢀ=ꢀ15 Hz, 1 arom. H), 8.56 [C18H17N2O] ).
(d, Jꢀ=ꢀ15 Hz, 2 arom. H), 8.74 (d, Jꢀ=ꢀ15 Hz, 1 arom. H), 9.33 (d,
Jꢀ=ꢀ14 Hz, 1 arom. H) ppm. HRMS ((+)-ESI): m/zꢀ=ꢀ289.1086 Acknowledgment: The authors are grateful to Kao Ger-
+
(calcd. 289.1089 for [C17H13N4O] ).
many GmbH, Darmstadt, for financial support.
3.4.3 2-(4-Chlorophenyl)naphtho[1,2-e][1,2,3,4]-
References
tetrazinium perchlorate (13c)
[1] H. Zollinger, Diazo Chemistry I, VCH, Weinheim, 1994.
[2] B. Giese, B. Kopping, T. Gobel, J. Dickhaut, G. Thoma, K.
J. Kulicke, F. Trach in Organic Reactions, Vol. 48 (Ed.: L. A.
Paquette), Wiley, NJ, 1996, p. 301.
[3] H. Bauer, A. R. Katritzky, J. Chem. Soc. 1954, 4394.
[4] E. Nölting, O. N. Witt, Ber. Dtsch. Chem. Ges. 1884, 17, 77.
[5] G. M. Norman, J. Chem. Soc., Trans. 1912, 101, 1913.
[6] D. W. Rangnekar, P. V. Tagdiwala, Dyes Pigm. 1986, 7, 289.
[7] L. K. Dyall, J. J. Harvey, T. B. Jarman, Aust. J. Chem. 1992, 45, 371.
[8] K. Yoshida, T. Koujiri, T. Horii, Y. Kubo, Bull. Chem. Soc. Jpn.
1990, 63, 1658.
It was prepared from 1-(p-chlorophenylazo)-2-napht-
ylamine (8c) as a brown solid; yield 84%, m.p. 185°C.
UV/vis (CH2Cl2): λmax (log ε):ꢀ=ꢀ494 nm (4.08). 1H NMR (TFA):
δꢀ=ꢀ7.70 (d, Jꢀ=ꢀ9.0 Hz, 2 arom. H), 8.17 (t, Jꢀ=ꢀ7.0 Hz, 1 arom.
H), 8.22 (t, Jꢀ=ꢀ7.0 Hz, 1 arom. H), 8.29 (d, Jꢀ=ꢀ8.0 Hz, 1 arom.
H), 8.42 (d, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 8.46 (d, Jꢀ=ꢀ9.0 Hz, 2 arom.
H), 8.83 (d, Jꢀ=ꢀ9.0 Hz, 1 arom. H), 9.26 (d, Jꢀ=ꢀ8.5 Hz, 1 arom.
H) ppm. HRMS ((+)-ESI): m/zꢀ=ꢀ293.0594 (calcd. 293.0594
+
for [C16H10ClN4] ).
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