Gas-phase thermolysis of 1-acylnaphtho[1,8-de][1,2,3]triazines. Interesting direct routes towards condensed naphtho[1,8-de]heterocyclic ring systems

Article abstract of DOI:10.1016/j.tet.2005.08.047

FVP pyrolysis of 1-acylnaphtho[1,8-de][1,2,3]triazines at 500°C and 10^-2 Torr gave exclusively the corresponding 2-substituted naphtho[1,8-de][1,3]oxazines. The latter was also obtained by static pyrolysis but in lower yield along with the corresponding N-(naphthalen-1-yl)acylamides. The reaction was studied kinetically and mechanistically.

Full text of DOI:10.1016/j.tet.2005.08.047

Tetrahedron 61 (2005) 10507–10513
Gas-phase thermolysis of 1-acylnaphtho[1,8-de][1,2,3]triazines.
Interesting direct routes towards condensed naphtho[1,8-de]
heterocyclic ring systems
Hanan Al-Awadi, Maher R. Ibrahim, Hicham H. Dib, Nouria A. Al-Awadi
*
and Yehia A. Ibrahim
Chemistry Department, Faculty of Science, Kuwait University, PO Box 5969, Safat 13060, Kuwait
Received 28 May 2005; revised 28 July 2005; accepted 11 August 2005
Available online 26 August 2005
Abstract—FVP pyrolysis of 1-acylnaphtho[1,8-de][1,2,3]triazines at 500 8C and 10K2 Torr gave exclusively the corresponding
2-substituted naphtho[1,8-de][1,3]oxazines. The latter was also obtained by static pyrolysis but in lower yield along with the corresponding
N-(naphthalen-1-yl)acylamides. The reaction was studied kinetically and mechanistically.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
along with other products.3 These two reactions resemble
very much the pyrolytic behaviour of the substituted
benzotriazoles 3, which have been extensively used for
the preparation of many interesting heterocyclic systems 4.4,5
Thus, derivatives of indole,4,6 carbazole,7 isomeric pyrido-
indoles,7d,8 pyrido[1,2-a]benzimidazole,8 benzimdazo[1,2-
a]pyrimidine,9 benzimdazo[1,2-a]pyridazine,9 benz-
imidazo[2,1-a]isoquinoline,10 benzimidazo[1,2-b]cinnoline,4
benzimidazo[2,1-b]benzothiazole,11 phenanthridine,12
benzoxazole,10,13 and quinolines14 as well as other
heterocyclic systems became readily available. Similarity
of the pyrolytic behaviour of benzotriazole and naphtho[1,8-
de][1,2,3]triazine derivatives lies in the fact that they both
undergo elimination of N2 followed by intramolecular
cyclization with the appropriate substituent (Scheme 1).
Thus, it is expected that pyrolysis of the appropriately
substituted naphtho[1,8-de][1,2,3]triazine derivatives
would open an important synthetic route to many condensed
heterocyclic systems, condensed on the peri positions of the
naphthalene ring. Some diradicals were generated from
1-alkylnaphtho[1,8-de][1,2,3]triazine derivatives and
1-acetylnaphtho[1,8-de][1,2,3]triazine by photolysis.15
However, no intramolecular cyclization of these photo-
lytically generated diradicals could be proved.15
In a previous publication1 we reviewed the flash vacuum
pyrolysis (FVP) of cinnolines, 1,2,3-benzotriazines and
1,2,4-benzotriazines, which have been shown to give direct
and easy access to many interesting compounds, some of
which are otherwise difficult to obtain. The primary step in
the pyrolysis of these compounds involves mainly N2
elimination, yielding the corresponding diradical inter-
mediates. On the other hand, pyrolysis of thieno[3,2-
e][1,2,4]triazines has been shown to follow in part the
same initial step (–N2), in addition to another important
pathway leading to N–N cleavage followed by several
rearrangements and/or fragmentation leading finally to
interesting heterocyclic systems.1
In continuation of our recent interest in the pyrolytic
behaviour of the above mentioned ring systems, we describe
in the present work the pyrolytic behaviour of naphtho[1,8-
de][1,2,3]triazine derivatives. Little attention has been
directed towards such interesting chemistry. Thus, pyrolysis
of 1-arylnaphtho[1,8-de][1,2,3]triazines 1 has been shown
to give the corresponding 7H-benzo[kl]acridine derivatives
2.2 The 8-nitro derivative of 2 has been prepared in a very
low yield from the corresponding triazine 1 (ArZo-
nitrophenyl) by heating with a large excess of (EtO)3P
In order to study the potential application of naphtho[1,8-
de][1,2,3]triazine in pyrolytic synthesis we describe in the
present work, the pyrolytic reactions of 1-acylnaphtho[1,8-
de][1,2,3]triazines 6 together with kinetic and suggested
mechanism for this pyrolytic reaction in comparison with
the analogous benzotriazole derivatives.
Keywords: FVP; Naphtho[1,8-de][1,2,3]triazines; Naphtho[1,8-de][1,3]
oxazines; Heterocycles.
Corresponding author. Tel.: C965 9464215; fax: C965 4836127;
e-mail: yehiaai@kuc01.kuniv.edu.kw
*
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.08.047

10508
H. Al-Awadi et al. / Tetrahedron 61 (2005) 10507–10513
Scheme 1.
2. Results and discussion
acyl derivatives 6a–f (50–60% yields) upon treatment 5 in
CH2Cl2 and triethylamine at 0 8C with the appropriate acid
chloride. This acylation reaction has been found to give a lot
of tarry materials and other minor by-products (Scheme 2).
2.1. Pyrolysate composition and reaction pathway
Literature shows that only the 1-acetyl derivative 6a has
been prepared in 32% yield by reacting 5 with NaH in dry
ether followed by heating at reflux with acetyl chloride.15 In
the present investigation, we have been able to prepare the
FVP of each of 6a–f at 500 8C and 0.02 Torr gave the
corresponding pure 2-substituted naphtho[1,8-de][1,3]-
oxazines 7a–f in 48–65% yields. On the other hand, gas
C, 0.6 mbar)
Scheme 2.

H. Al-Awadi et al. / Tetrahedron 61 (2005) 10507–10513
10509
determined by HPLC (Table 1) and by 1H NMR
spectroscopy.
Table 1. Pyrolysis products of 1-acylnaphtho[1,8-de][1,2,3]triazines 6a–d
Substrate
Pyrolysis products (% yields)
6a
FVP
7a
63
28
19
8a
0
14
43
Scheme 3 illustrates possible mechanistic routes explaining
the formation of the products 7, 8 obtained in the present
pyrolytic study. The reaction starts by extrusion of N2 to
give the diradicals 9a–f, which then undergo intramolecular
cyclization to give the corresponding oxazines 7a–f. The
latter are the only observed product from FVP of 6a–f. In the
present study, attempts to investigate the possible intra-
molecular cycloaddition of the diradical 9 on C]C by using
the o-allyloxybenzoyl derivative 6f did not succeed, and we
only obtained the normal reaction observed with the other
derivatives 6a–e. The formation of the acylamide deriva-
tives 8 can be achieved by addition of hydrogen to the
diradicals 9, and this process seems to be appreciable in the
static pyrolysis due to the longer reaction times and also as a
result of charring of some of the materials, resulting in the
availability of hydrogen in the reaction medium. This
assumption was substantiated by the fact that repeating all
static pyrolysis reaction in the presence of cyclohexene
(good hydrogen source)1 led to an increase in the percent
yields of the corresponding derivatives 8, and a decrease of
the corresponding oxazines 7 as shown in Table 1.
Static
Static (cyclohexene)
6b
FVP
7b
56
40
12
8b
0
28
52
Static
Static (cyclohexene)
6c
FVP
7c
65
43
19
8c
0
29
54
Static
Static (cyclohexene)
6d
FVP
7d
61
46
18
8d
0
36
56
Static
Static (cyclohexene)
6e
FVP
7e
59
39
22
8e
0
15
41
Static
Static (cyclohexene)
6f
FVP
7f
8f
0
17
40
48
38
14
Static
Static (cyclohexene)
2.2. Kinetic data and comparative molecular reactivity
The rates of gas-phase thermolysis of the 1-aroylnaphtho-
triazines 6b,c and 6e, were measured over the temperature
range 347–428 K with an average range of 55 K per
substrate, in order to ensure reliable activation parameters
for the first-order gas-phase elimination process of these
compounds.16 The kinetic data is given in Table 2. Each rate
constant recorded is an average from at least three
independent evaluations of the rate at each reaction
temperature, and are in agreement to within G2% rate
spread. The Arrhenius parameters were obtained from
strictly linear correlations over O85% reaction. The
Arrhenius parameters and rate constants (k/sK1) calculated
at 450 K for substrates 6b,c and 6e are summarized in
Table 2. The rate data of related 1-acylbenzotriazoles has
been reported in an earlier publication and are tabulated in
Table 3.17 The reaction mechanism (Scheme 3) and the
kinetic data allow the following conclusions and structure/
reactivity correlations to be made:
Scheme 3.
phase pyrolysis of 6a–f at 170–180 8C and 0.06 mbar gave a
mixture of 7a–f and N-(naphthalen-1-yl)acylamides 8a–f in
the percentage yields indicated in Table 1.
The pyrolysates were qualitatively and quantitatively
Table 2. Rate coeffecients (k/sK1), Arrhenius parameters of 1-acylnaphtho[1,8-de][1,2,3]triazines 6b,c,e
Compound
T/K
104 k/sK1
log A/sK1
Ea/kJ molK1
88.767G5.48
k450 K/sK1
6b
389.25
409.25
418.85
428.85
448.55
374.15
383.85
403.45
413.25
433.15
443.35
374.25
393.85
413.45
423.40
0.966
3.343
4.885
13.01
32.95
0.458
0.883
3.127
7.564
21.07
40.72
0.597
2.565
11.70
20.18
7.727G0.69
3.508!10K3
6c
6e
8.164G0.28
9.143G0.33
90.779G2.21
96.972G2.50
5.641!10K3
1.046!10K3

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H. Al-Awadi et al. / Tetrahedron 61 (2005) 10507–10513
Table 3. krel of 1-acylnaphtho[1,8-de][1,2,3]triazines compared to the corresponding 1-acylbenzotriazoles (ArCOBT)
Ar
(6b,c,e) kN450 K/sK1
ArCOBT kBT450 K/sK1
KrelZkN/kBT
C6H5
p-ClC6H5
p-H3COC6H5
3.508!10K3
5.641!10K3
1.046!10K3
2.543!10K3
2.753!10K3
8.243!10K4
1.38
1.94
4.66
% The aroylbenzotriazoles are less reactive than
aroylnapthotriazines. This structural effect could
be rathionalized in terms of resonance stabiliz-
ation extended by conjugation in naphthotriazine
more than it does in benzotriazole.
Each substrate (0.2 g) and cyclohexene (0.1 g) were
introduced in the reaction tube (1.5!12 cm Pyrex), cooled
in liquid nitrogen, sealed under vacuum (0.06 mbar) and
placed in the pyrolyser for 15 min at 170–180 8C. The
products were separated by column chromatography using
Merck Al-silica gel 60F254, with EtOAC–petroleum ether
(40/60) (1–10% of EtOAc) to give successively 7 followed
by 8.
% We have noted earlier4 that the effect of
substituents not conjugated to the benzotriazole
radical centre of the benzotriazole biradical
intermediate are moderate and that electron-
withdrawing groups tend to increase the molecu-
lar reactivity of BT compounds while electron-
donating groups have an opposite effect. This is
also the case with the naphthotriazine substrates
6a–e under study as evidenced by their rates of
pyrolysis (Table 2).
(C) Flash vacuum pyrolysis of 6a–d
The apparatus used was similar to the one, which has been
described in our recent publications.1,7 The sample was
volatilized from a tube in a Bu¨chi Kugelrohr oven through a
30!2.5 cm horizontal fused quartz tube. This was heated
externally by a Carbolite Eurotherm tube furnace MTF-12/
38A to a temperature of 500 8C, the temperature being
monitored by a Pt/Pt-13%Rh thermocouple situated at the
centre of the furnace. The products were collected in a
U-shaped trap cooled in liquid nitrogen. The whole system
was maintained at a pressure of 10K2 Torr by an Edwards
Model E2M5 high capacity rotary oil pump, the pressure
being measured by a Pirani gauge situated between the cold
trap and the pump. Under these conditions the contact time
in the hot zone was estimated to bey10 ms. The different
zones of the products collected in the U-shaped trap were
3. Conclusions
The present study offers interesting routes towards many
condensed heterocyclic systems condensed on the peri
positions of the naphthalene ring, of which many derivatives
exhibit interesting photo-emission properties. Of the
compounds synthesized in the present work some
interesting studies on the fluorescence spectra of a series
of 1-aminonaphthalene derivatives,18a and naphtho[1,8-
de][1,3]oxazine derivates were reported.18b
1
analyzed by H, 13C NMR, IR and GC–MS. Relative and
1
percent yields were determined from H NMR.
4.2. Pyrolysis products
4. Experimental
4.2.1. Naphtho[1,8-de][1,3]oxazine 7.
4.2.1.1. 2-Methylnaphtho[1,8-de][1,3]oxazine 7a.
Colourless crystals from petroleum ether (40–60), mp 68–
70 8C (lit.19 mp 68 8C). LCMS m/zZ184 (MC1). 1H NMR
(CDCl3): d 7.40 (d, 1H, JZ8.4 Hz), 7.33 (m, 2H), 7.28 (d,
1H, JZ8.0 Hz), 6.93 (d, 1H, JZ7.0 Hz), 6.69 (d, 1H, JZ
7.8 Hz), 2.27 (s, 3H, CH3).
All melting points are uncorrected. IR spectra were recorded
in KBr disks using Perkin Elmer System 2000 FT-IR
spectrophotometer. 1H and 13C NMR spectra were recorded
on a Bruker DPX 400, 400 MHz super-conducting NMR
spectrometer. LCMS were measured using Agilent 1100
series LC/MSD with an API-ES/APCI ionization mode.
Microanalyses were performed on LECO CHNS-932
Elemental Analyzer.
4.2.1.2. 2-Phenylnaphtho[1,8-de][1,3]oxazine 7b.
Colourless crystals from ethanol, mp 135–136 8C (lit.20
mp 134 8C). LCMS m/zZ246 (MC1). IR: 3053, 1638,
4.1. Pyrolysis of 6a–f: general procedures
1
1597, 1373, 1315, 1253, 1092, 822, 764, 693. H NMR
(CDCl3): d 8.24 (d, 2H, JZ7.8 Hz), 7.52 (m, 3H), 7.43 (t,
1H, JZ8.0 Hz), 7.33 (m, 3H), 7.10 (dd, 1H, JZ7.8, 1.2 Hz),
6.86 (dd, 1H, JZ7.8, 1.2 Hz). 13C NMR (CDCl3): d 155.3
(C), 149.9 (C), 137.9 (C), 134.3 (C), 131.8 (CH), 131.2 (C),
128.8 (CH), 128.4 (2CH), 127.8 (2CH), 122.6 (CH), 123.2
(CH), 120.9 (CH), 119.0 (C), 117.2 (CH), 106.2 (CH). Anal.
Calcd for C17H11NO (245.3): C 83.25; H 5.52; N 5.71.
Found: C 83.20; H 4.95; N 5.62.
(A) Static pyrolysis of 6a–f
Each substrate (0.2 g) was introduced in the reaction tube
(1.5!12 cm Pyrex), cooled in liquid nitrogen, sealed under
vacuum (0.06 mbar) and placed in the pyrolyser for 15 min
at 170–180 8C, a temperature that is required for complete
pyrolysis of the substrate as indicated by a preliminary
HPLC study. The products were separated by column
chromatography using Merck Al-silica gel 60F254, with
EtOAc–petroleum ether (40/60) (1–10% of EtOAc) to give
successively 7 followed by 8.
4.2.1.3. 2-(4-Chlorophenyl)naphtho[1,8-de][1,3]oxa-
zine 7c. Pale yellow crystals from ethanol, mp 140–
142 8C. LCMS m/zZ280 (MC1), 282 (MC3). IR: 3060,
1638, 1590, 1487, 1374, 1252, 1091, 1015, 823, 768, 724.
(B) Static pyrolysis of 6a–f with cyclohexene

H. Al-Awadi et al. / Tetrahedron 61 (2005) 10507–10513
10511
1H NMR (CDCl3): d 8.17 (dd, 2H, JZ8.4, 1.7 Hz), 7.48 (dd,
2H, JZ8.4, 1.7 Hz), 7.44 (d, 1H, JZ8 Hz) 7.38 (m, 2H),
7.34 (t, 1H, JZ8 Hz), 7.08 (dd, 1H, JZ7.6, 1.0 Hz), 6.83
(dd, 1H, JZ7.3, 1.0 Hz). 13C NMR (CDCl3): d 154.4 (C),
149.7 (C), 138.1 (C), 137.6 (C), 134.3 (C), 129.7 (C), 129.1
(2CH), 128.8 (CH), 128.7 (2CH), 127.8 (CH), 123.5 (CH),
121.0 (CH), 118.9 (C), 117.3 (CH), 106.1 (CH). Anal. Calcd
for C17H10ClNO (279.7): C 73.00; H 3.60; N, 5.01. Found:
C 73.02; H 3.55; N 5.00.
4.2.2.3. 4-Chloro-N-(naphthalen-1-yl)benzamide 8c.
Colourless crystals from petroleum ether (80–100), mp
208–210 8C. LCMS m/zZ282 (MC1), 284 (MC3). IR
(KBr): 3193 (br), 3047, 1641, 1596, 1483, 1310, 1090, 845,
1
803, 771, 677. H NMR (DMSO): d 10.54 (br, 1H, NH),
8.11 (d, 2H, JZ8.2 Hz), 7.96 (m, 2H), 7.88 (d, 1H, JZ
7.7 Hz), 7.65 (d, 2H, JZ8.1 Hz), 7.57 (m, 4H). 13C NMR
(CDCl3): d 166.3 (CO), 137.6 (C), 134.8 (C), 134.6 (C),
134.2 (C), 130.8 (2CH), 130.2 (C), 129.6 (2CH), 129.1
(CH), 127.5 (CH), 127.2 (CH), 127.1 (CH), 126.6 (CH),
125.0 (CH), 124.3 (CH). Anal. Calcd for C17H12ClNO
(281.7): C 72.47; H 4.29; N 4.97. Found: C 72.40; H 4.21; N
4.86.
4.2.1.4. 2-(4-Methylphenyl)naphtho[1,8-de][1,3]oxa-
zine 7d. Yellow crystals from ethanol, mp 158–160 8C.
LCMS m/zZ260 (MC1). IR: 3061, 2961, 2923, 2853,
1
1638, 1594, 1449, 1376, 1251, 1089, 816, 760. H NMR
4.2.2.4. 4-Methyl-N-(naphthalen-1-yl)benzamide 8d.
Colourless crystals from ethanol, mp 170–172 8C (lit.23 mp
171–173 8C). LCMS m/zZ262 (MC1). 1H NMR (CDCl3):
d 8.22 (br s, 1H, NH), 8.06 (d, 1H, JZ8.0 Hz), 7.91 (m, 4H),
7.77 (d, 1H, JZ8.2 Hz), 7.56 (m, 3H), 7.36 (d, 2H, JZ
8.0 Hz), 2.47 (s, 3H, CH3). 13C NMR (CDCl3): d 164.6
(C]O), 140.9 (C), 132.5 (C), 130.8 (C), 130.3 (C), 127.9
(2CH), 127.2 (CH), 125.8 (C), 125.6 (2CH), 124.8 (CH),
124.4 (CH), 124.3 (CH), 124.2 (CH), 119.5 (CH), 119.0
(CH), 19.9 (CH3). Anal. Calcd for C18H15NO (361.3): C
82.73; H 5.79; N 5.36. Found: C 82.59; H 5.77; N 5.44.
(CDCl3): d 8.12 (d, 2H, JZ8.2 Hz), 7.34 (m, 4H), 7.32 (d,
2H, JZ8.1 Hz), 7.08 (dd, 1H, JZ7.0, 1.0 Hz), 6.84 (dd, 1H,
JZ7.0, 1.0 Hz), 2.46 (s, 3H, CH3). 13C NMR (CDCl3): d
153.8 (C), 148.3 (C), 140.8 (C), 136.4 (C), 132.7 (C), 127.5
(2CH), 127.1 (CH), 126.8 (C), 126.1 (2CH), 126.0 (CH),
121.4 (CH), 119.2 (CH), 117.4 (C), 115.3 (CH), 104.4 (CH),
20.0 (CH3). Anal. Calcd for C18H13NO (259.3): C 83.38; H
5.05; N 5.40. Found: C 83.30; H 4.95; N 5.42.
4.2.1.5. 2-(4-Methoxyphenyl)naphtho[1,8-de][1,3]oxa-
zine 7e. Yellow crystals from ethanol, mp 142–143 8C.
LCMS m/zZ276 (MC1). IR: 3060, 1638, 1594, 1499,
1
4.2.2.5. 4-Methoxy-N-(naphthalen-1-yl)benzamide 8e.
Colourless crystals from ethanol, mp 205–206 8C (lit.24 mp
203–205 8C). LCMS m/zZ278 (MC1). 1H NMR (CDCl3):
d 8.17 (br, 1H, NH), 8.04 (d, 1H, JZ7.8 Hz), 7.98 (d, 2H,
JZ8.6 Hz), 7.92 (t, 2H, JZ7.4 Hz), 7.76 (d, 1H, JZ
8.2 Hz), 7.55 (m, 3H), 7.03 (d, 2H, JZ8.6 Hz), 3.92 (s, 3H,
OCH3).
1376, 1251, 1089, 816, 760. H NMR (CDCl3): d 8.19 (d,
2H, JZ8.8 Hz), 7.42–7.30 (m, 4H), 7.08 (d, 1H, JZ6.8 Hz),
7.01 (d, 2H, JZ8.8 Hz), 6.83 (dd, 1H, JZ7.0, 1.0 Hz), 3.91
(s, 3H). Anal. Calcd for C18H13NO2 (275.3): C 78.53; H
4.72; N 5.09. Found: C 78.50; H 4.55; N 4.92.
4.2.1.6. 2-(2-Allyloxyphenyl)naphtho[1,8-de][1,3]oxa-
zine 7f. Colourless crystals from ethanol, mp 98–100 8C.
LCMS m/zZ302 (MC1). IR: 3060, 2910, 2863, 1691,
4.2.2.6. 2-Allyloxy-N-(naphthalen-1-yl)benzamide 8f.
Colorless crystals from MeOH/H2O, mp 102–104 8C.
LCMSZ304 (MC1). IR (KBr): 3356, 3051, 1660, 1598,
1544, 1501, 1483, 1403, 1342, 1297, 1220, 994, 934, 746,
1
1598, 1486, 1450, 1372, 1315, 977, 857, 765. H NMR
(CDCl3): d 8.34 (dd, 1H, JZ6.8, 1.8 Hz), 7.66 (dd, 1H, JZ
7.6, 1.4 Hz), 7.53–7.42 (m, 6H), 7.09 (t, 1H, JZ8.0 Hz),
6.95 (d, 1H, JZ8.4 Hz), 5.90 (m, 1H), 5.29 (dd, 1H, JZ
17.2, 1.4 Hz), 5.09 (dd, 1H, JZ10.4, 1.4 Hz), 4.61 (d, 2H,
JZ4.8 Hz). 13C NMR (CDCl3): d 171.4 (C), 155.4 (C),
134.2 (C), 132.7 (C), 132.6 (CH]CH2), 131.7 (CH), 129.0
(CH), 128.9 (C), 128.8 (CH), 128.5 (CH), 127.7 (CH), 126.2
(C), 122.4 (CH), 121.5 (CH), 120.8 (CH), 117.1 (]CH2),
116.5 (C), 112.2 (CH), 109.9 (CH), 69.4 (CH2). Anal. Calcd
for C20H15NO2 (301): C 79.73; H 4.98; N 4.6. Found: C
79.70; H 4.95; N 4.62.
1
630. H NMR (CDCl3): d 10.44 (br s, 1H, NH), 8.43 (dd,
1H, JZ7.8, 1.4 Hz), 8.39 (d, 1H, JZ7.6 Hz), 8.04 (d, 1H,
JZ8.8 Hz), 7.92 (d, 1H, JZ6.4 Hz), 7.72 (d 1H, JZ
8.2 Hz), 7.58–7.52 (m, 4H), 7.21 (t, 1H, JZ7.6 Hz), 7.12 (d,
1H, JZ8.3 Hz), 6.25 (m, 1H), 5.58 (d, 1H, JZ17.2 Hz),
5.46 (d, 1H, JZ10.3 Hz), 4.89 (d, 2H, JZ5.8 Hz). 13C
NMR (CDCl3): d 163.6 (C), 156.5 (C), 134.1 (C), 133.3
(CH), 132.9 (CH), 131.9 (CH), 128.8 (CH), 126.6 (C), 126.2
(CH), 125.9 (CH), 125.8 (C, CH), 124.9 (CH), 122.3 (C),
122.1 (CH), 121.0 (CH), 120.5 (]CH2, Dept), 119.8 (CH),
112.7 (CH), 70.6 (CH2). Anal. Calcd for C20H17NO2
(303.3): C 79.19; H 5.65; N 4.62. Found: C 79.10; H 5.59;
N 4.53.
4.2.2. N-[Naphthalen-1-yl]acylamides 8.
4.2.2.1. N-[Naphthalen-1-yl]acetamide 8a. Colourless
crystals from petroleum ether (40–60), mp 157–158 8C
(lit.21a,b mp 159–160 8C). LCMS m/zZ186 (MC1). 1H
NMR (DMSO-d6): d 10.01 (br, 1H, NH), 8.00 (m, 2H), 7.74
(d, 1H, JZ8 Hz), 7.68 (d, 1H, JZ8 Hz, 7.52 (m, 2H), 7.46
(t, 1H, JZ8 Hz), 2.17 (s, 3H, CH3).
4.2.3. Naphtho[1,8-de][1,2,3]triazine 5. To a cold (0 8C)
solution of 1,8-diaminonaphthalene (1.58 g, 10 mmol) in
aqueous acetic acid (50%, 30 mL) was added portionwise
with stirring solid sodium nitrite (0.8 g, 11 mmol). Stirring
was then continued for 5 h at 0 8C. The dark brown
precipitate was collected and washed with water and then
recrystallized from EtOH/H2O to give reddish brown
powder, yield 1.0 g (60%), mp 244–246 8C (dec.) (lit.25
mp 230 8C, decomp.) LCMS m/zZ170 (MC1). IR: 3500–
2500 (br), 1642, 1593, 1464, 1356, 1333, 1281, 1184, 1158,
1121, 1086, 887, 815, 758. 1H NMR (DMSO-d6): d 13.29 (s,
4.2.2.2. N-(Naphthalen-1-yl)benzamide 8b. Colourless
crystals from ethanol, mp 167–168 8C (lit.22 mp 164–
1
165 8C). LCMS m/zZ248 (MC1). H NMR (CDCl3): d
8.22 (br, 1H, NH), 8.10 (d, 1H, JZ7 Hz), 8.03 (d, 2H, JZ
7.2 Hz), 7.94 (m, 2H), 7.78 (d, 1H, JZ8.2 Hz), 7.63 (t, 1H,
JZ7.2 Hz) 7.58 (m, 5H).

10512
H. Al-Awadi et al. / Tetrahedron 61 (2005) 10507–10513
1H, NH), 7.26 (m, 2H), 7.13 (t, 1H, JZ8.0 Hz), 7.03 (d, 1H,
JZ8.4 Hz), 6.89 (d, 1H, JZ8.2 Hz), 6.13 (d, 1H, JZ
7.2 Hz). 13C NMR (DMSO): d 139.4 (C), 133.9 (C), 133.3
(C), 129.6 (CH), 129.4 (CH), 123.9 (CH), 118.7 (C), 118.6
(CH), 114.4 (CH), 99.0 (CH).
134.3 (C), 132.9 (C), 131.4 (C), 130.2 (2CH), 129.3 (C),
128.8 (2CH), 128.7 (CH), 128.5 (CH), 127.9 (CH), 122.3
(CH), 121.3 (CH), 116.8 (C), 109.5 (CH), 21.7 (CH3). Anal.
Calcd for C18H13N3O (287.3): C 75.25; H 4.56; N 14.62.
Found: C 74.98; H 4.49; N 14.60.
4.3. 1-Acylnaphtho[1,8-de][1,2,3]triazines 6a–f: general
procedure
4.3.5. 1-(4-Methoxybenzoyl)naphtho[1,8-de][1,2,3]tria-
zine 6e. Yield 1.8 g (60%). Yellow crystals from EtOH,
mp 158–160 8C. LCMS m/zZ304 (MC1). IR: 3056, 2839,
1686, 1603, 1510, 1373, 1306, 1259, 1176, 1032, 976, 862,
To a stirred cold (0 8C) suspension of 5 (1.69 g, 10 mmol) in
dichloromethane (25 mL) was added TEA (1 mL) followed
by dropwise addition of the appropriate acid chloride
(12 mmol). After complete addition the reaction mixture
was kept stirring at 0 8C for 2 h and then at room
temperature overnight. After washing with sodium
bicarbonate solution (10%, 100 mL) the organic layer was
separated and dried with anhydrous sodium sulfate. The
solvent was then evaporated in vacuo and the residue was
crystallized to give the corresponding products 6a–f.
1
840, 824, 759. H NMR (CDCl3): d 7.95 (dd, 1H, JZ7.0,
1.5 Hz), 7.86 (d, 2H, JZ8.8 Hz), 7.62 (dd, 1H, JZ7.6,
1.6 Hz), 7.49–7.39 (m, 4H), 6.98 (d, 2H, JZ8.8 Hz), 3.91 (s,
3H). 13C NMR (CDCl3): d 171.0 (C]O), 162.9 (C), 134.5
(C), 133.0 (C), 132.7 (2CH), 129.4 (C), 128.7 (CH), 128.4
(CH), 127.9 (CH), 126.1 (C), 122.1 (CH), 121.0 (CH), 116.9
(C), 113.4 (2CH), 109.1 (CH), 55.5 (OCH3). Anal. Calcd for
C18H13N3O2 (303.3): C 71.28; H 4.32; N 13.85. Found: C
71.21; H 4.41; N 13.64.
4.3.1. 1-Acetylnaphtho[1,8-de][1,2,3]triazine 6a. Yield
1.3 g (61%.) Yellow crystals from petroleum ether (80–
100), mp 98–100 8C (lit.15 97–98). LCMS m/zZ212 (MC
1). IR: 3063, 1707, 1628, 1430,1366, 1296, 1033, 944, 828,
4.3.6. 1-(2-Allyloxybenzoyl)naphtho[1,8-de][1,2,3]tria-
zine 6f. Yield 1.6 g (50%). Yellow oil. LCMS m/zZ330
(MC1). 1H NMR (CDCl3): d 7.84 (dd, 1H, JZ7.6, 1.6 Hz),
7.45 (dd, 1H, JZ8.0, 1.6 Hz), 7.43 (d, 1H, JZ8.0 Hz),
7.39–7.30 (m, 3H), 7.06 (t, 2H, JZ8.0 Hz), 7.02 (d, 1H, JZ
7.0 Hz), 6.75 (d, 1H, JZ6.8 Hz), 6.09 (m, 1H), 5.55 (dd,
1H, JZ15.6, 1.4 Hz), 5.30 (dd, 1H, JZ10.8, 1.4 Hz), 4.68
(m, 2H). Anal. Calcd for C20H15N3O2 (329): C 72.94; H
4.55; N 12.76. Found: C 72.83; H 4.41; N 12.68.
1
771. H NMR (CDCl3): d 8.22 (dd, 1H, JZ7.6, 1.0 Hz),
7.63 (d, 1H, JZ8.4 Hz), 7.54 (d, 1H, JZ7.0 Hz), 7.48–7.38
(m, 3H), 2.72 (s, 3H, CH3). 13C NMR (CDCl3): d 173.6
(C]O), 134.3 (C), 132.7 (C), 128.8 (CH), 128.7 (C), 128.6
(CH), 127.7 (CH), 122.3 (CH), 121.6 (CH), 116.5 (C), 110.3
(CH), 24.7 (CH3). Anal. Calcd for C12H9N3O (211.2): C
68.24; H 4.29; N 19.65. Found: C 68.31; H 4.21; N 19.55.
Acknowledgements
4.3.2. 1-Benzoylnaphtho[1,8-de][1,2,3]triazine 6b. Yield
1.6 (60%). Yellow crystals from EtOH/CHCl3, mp 145–
147 8C. LCMS m/zZ274 (MC1). IR: 3058, 1689, 1632,
1578, 1524, 1484, 1446, 1410, 1339, 1307, 1255, 1174,
1037, 976, 858, 825, 764, 703. 1H NMR (CDCl3): d 8.11 (d,
1H, JZ7.4 Hz), 7.81 (d, 2H, JZ7.3 Hz), 7.67 (d, 1H, JZ
7.6 Hz), 7.57 (t, 1H, JZ7.6 Hz), 7.50–7.43 (m, 6H). 13C
NMR (CDCl3): d 171.9 (C]O), 140.4 (C), 134.5 (C), 134.2
(C), 132.9 (C), 131.8 (CH), 139.9 (2CH), 128.8 (CH), 128.7
(CH), 128.1 (2CH), 127.8 (CH), 122.5 (CH), 121.5 (CH),
116.7 (C), 119.8 (CH). Anal. Calcd for C17H11N3O (273.3):
C 74.71; H 4.06; N 15.38. Found: C 74.61; H 4.21; N 14.05.
The support of the University of Kuwait received through
research grant no. SC06/01 and the facilities of ANALAB
and SAF (grants no. GS01/01, GS02/01, GS03/01) are
gratefully acknowledged.
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2004, 60, 9121–9130.
4.3.3. 1-(4-Chlorobenzoyl)naphtho[1,8-de][1,2,3]triazine
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