Eco-friendly synthesis of highly substituted functionalized oxazines by FeCl3/SiO2 nanoparticles

Article abstract of DOI:10.1007/s00706-012-0850-1

An efficient and modern method for the preparation of amidoalkyl naphthols in the presence of silica nanoparticle-supported ferric chloride under thermal solvent-free conditions is explained. The prepared amidoalkyl naphthols were converted to 1,3-oxazine

Full text of DOI:10.1007/s00706-012-0850-1

Monatsh Chem (2013) 144:687–693
DOI 10.1007/s00706-012-0850-1
ORIGINAL PAPER
Eco-friendly synthesis of highly substituted functionalized
oxazines by FeCl3/SiO2 nanoparticles
•
Javad Safaei Ghomi Safura Zahedi
Received: 21 December 2011 / Accepted: 23 August 2012 / Published online: 22 September 2012
Ó Springer-Verlag 2012
Abstract An efficient and modern method for the prep-
aration of amidoalkyl naphthols in the presence of silica
nanoparticle-supported ferric chloride under thermal sol-
vent-free conditions is explained. The prepared amidoalkyl
naphthols were converted to 1,3-oxazines by Vilsmeier
reagent in the presence of FeCl3/SiO2 nanoparticles. This
method provides a novel route to synthesis amidoalkyl
naphthol and 1,3-oxazine derivatives in terms of good
yields, short reaction times, and recyclable catalyst.
via different methods. However, some of the reported
methods suffer from disadvantages such as long reaction
times [10] and harsh reaction conditions [11]. Therefore, to
avoid these limitations, the discovery of a new, easily
available catalyst with high catalytic activity and short
reaction time for the preparation of 1,3-oxazines is still
desirable.
In a desired procedure, 1,3-oxazines were prepared by
amidoalkyl naphthols, which were synthesized by Lewis or
Brønsted acid catalysts such as p-toluenesulfonic acid [12],
H2NSO3H [13], oxalic acid [14], Fe(HSO4)3 [15], Sr(OTf)2
[16], I2 [17], K5CoW12O40Á3H2O [18], HPMo [19],
Yb(OTf)3 in ionic liquid [20], indion-130 [21], montmoril-
lonite K10 [22], TMSCl/NaI [23], Al2O3–HClO4 [24], InCl3
[25], 2,4,6-trichloro-1,3,5-triazine [26], CuPW and CuPMo
[27], FeCl3/SiO2[28], H4SiW12O40 [29], and CPTS [30].
We herein describe a new, convenient method for the
synthesis of amidoalkyl naphthols by multicomponent
reaction of 2-naphthol, aromatic aldehydes, and acetamide
catalyzed by FeCl3/SiO2 nanoparticles (NPs) under sol-
vent-free conditions. Then, the prepared amidoalkyl
naphthols were treated with Vilsmeier reagent in the
presence of FeCl3/SiO2 NPs to give oxazine derivatives
(Scheme 1; Table 1).
Keywords Amidoalkyl naphthol Á Oxazine Á
Heterogeneous catalysis Á One-pot synthesis Á Solvent-free
Introduction
The synthesis of 1,3-oxazines has attracted attention in the
past because of their potential as antibiotics [1], antitumor
agents [2], analgesics [3], and anticonvulsants [4]. In
addition, benzo-1,3-oxazines are known to be biologically
active as anti-malarial [5], antianginal [6], anti-hyperten-
sive [7], and potent anti-rheumatic agents [8]. Hence, the
synthesis of these derivatives is of considerable interest.
Several methods for the preparations of 1,3-oxazine
derivatives have previously been reported [9]. The Vils-
meier-Haack reagent is an efficient, economical, and mild
reagent for the synthesis of highly functionalized oxazines
Results and discussion
It was of particular interest to us to study the application of
FeCl3/SiO2 NPs to the intramolecular cyclization of
amidoalkyl naphthols by Vilsmeier reagent. Hence, first we
prepared amidoalkyl naphthols as precursors to the prepa-
ration of oxazines. In order to select the best catalyst, the
reaction was carried out by treatment of benzaldehyde,
2-naphthol, and acetamide, and also the cyclization of
J. S. Ghomi (&)
Department of Chemistry, Qom Branch,
Islamic Azad University, Qom, Islamic Republic Iran
e-mail: safaei@kashanu.ac.ir
S. Zahedi
Faculty of Chemistry, Department of Organic Chemistry,
University of Kashan, Kashan 51167, Islamic Republic Iran
123

688
J. S. Ghomi, S. Zahedi
Scheme 1
Table 1 Synthesis of amidoalkyl naphthols 4 and 1,3-oxazines 5 in the presence of FeCl3/SiO2 NPs (Scheme 1)
Entry
Ar
4
Time/min
Yielda/%
M.p./°C (lit. m.p./°C)
5
Time/min
Yielda/%
M.p./°C
1
Ph
4a
4b
4c
4d
4e
4f
10
7
88
95
92
90
89
80
84
85
90
80
85
82
245–246 (242–244) [30]
247–249 (248–250) [28]
178–180 (179–182) [28]
223–225 (223–225) [28]
200–202 (202–204) [26]
222–223 (220–222) [26]
183–185 (185–186) [26]
220–222
5a
5b
5c
5d
5e
5f
30
30
30
30
30
30
30
30
30
30
30
30
88
92
92
88
80
79
79
82
88
87
85
82
235–237
263-264
255–257
232–234
209–210
219–221
205–206
228–229
237–239
241–243
250–252
245–247
2
4-NO2-Ph
2-NO2-Ph
4-Cl-Ph
3
8
4
8
5
2,4-Cl2-Ph
4-Me-Ph
4-MeO-Ph
4-i-Pr-Ph
4-Br-Ph
8
6
15
17
20
8
7
4g
4h
4j
5g
5h
5j
8
9
227–229 (228–230) [22]
226–227
10
11
12
a
4-OH-Ph
2,4-(MeO)2-Ph
1-Naphthyl
4k
4l
15
17
15
5k
5l
227–229
4m
210–220
5m
Yields refer to isolated products
Table 2 Catalytic activity of various catalysts
Entry Catalysta
Product 4
Product 5
Yieldb/% Time
Time
Yieldb/%
1
2
3
4
a
None
2 h
2 h
2 h
0
45
40
3 h
86 [10]
87
FeCl3
1.5 h
1.5 h
SiO2 NPs
87
FeCl3ÁSiO2 NPs 10 min 88 30 min 88
The reaction was carried out under solvent-free conditions
b
Isolated yield
prepared amidoalkyl naphthols in the presence of FeCl3,
SiO2 NPs, and FeCl3/SiO2 NPs. The best yields were
obtained in the presence of FeCl3/SiO2 NPs. Notably,
amidoalkyl naphthols could not be obtained under similar
Fig. 1 SEM image of FeCl3/SiO2 NPs
123

Eco-friendly synthesis of highly substituted functionalized oxazines
689
Table 3 The best experimental
Entry Catalyst/mg Product 4
conditions for preparation of
Product 5
Temp/°C Time/min Yielda/% Temperature/°C
Time/min Yielda/%
amidoalkyl naphthols 4 and
oxazines 5
1
2
3
4
5
6
7
8
0.05
0.05
0.05
0.1
90
110
130
90
30
25
20
25
10
10
10
10
56
64
69
73
88
88
88
88
Room temperature 120
0
35
67
55
68
88
88
88
50
80
40
60
80
80
80
60
50
50
40
30
30
30
0.1
110
130
110
110
0.1
0.2
0.3
a
Isolated yield
reaction conditions, even after a long time (2 h) in the
absence of the catalyst (Table 2), while cyclization reac-
tions have been reported without using a catalyst for a long
time (3 h) [10].
intermediate 8. The latter undergoes cyclization to inter-
mediate 9, which spontaneously undergoes dehydroxylation
to form the intermediate 10. Attack of another Vilsmeier
intermediate to 10 leads to the formation of intermediate 11,
the hydrolysis of which gives the product 5.
Table 2 clearly illustrates that, among four mentioned
catalysts, nano-silica-supported ferric chloride is an effec-
tive catalyst in terms of reaction times and yields of
product, because the nano-SiO2 support increases the sur-
face area contact of materials. In order to investigate the
morphology and particle size of FeCl3/SiO2 NPs, a SEM
image of FeCl3/SiO2 NPs is shown in Fig. 1. As can be
seen, the sample shows a nanocrystalline structure.
To determine the best experimental conditions, the
reaction of benzaldehyde, 2-naphthol, and acetamide was
considered the model. The best results were obtained in the
presence of 0.1 mg (0.4 mol %) FeCl3/SiO2 NPs under
solvent-free conditions at 110 °C. We next investigated the
cyclization reaction of amidoalkyl naphthols, and for this
we selected the model reaction of N-[(2-hydroxy-1-naph-
thyl)(phenyl)methyl]acetamide, DMF, and POCl3. After
several attempts, reasonable results were obtained in the
presence of 0.1 mg (0.4 mol %) FeCl3/SiO2 NPs at 80 °C.
The results are summarized in Table 3.
In summary, we have introduced novel ferric chloride-
supported silica nanoparticles (FeCl3/SiO2 NPs) as highly
efficient and green catalysts for organic transformations.
Currently, the synthesis of amidoalkyl naphthols and
oxazine derivatives was efficiently catalyzed by FeCl3/
SiO2 NPs. These applications are attractive because of the
considerable advantages such as simplicity of operation,
high product yields, short reaction times, solvent-free
conditions, and the use of an inexpensive and recyclable
catalyst.
Experimental
All reagents were purchased from Merck and Aldrich and
used without further purification. The reactions were
monitored by TLC using 0.2-mm Merck silica gel 60 F254
pre-coated plates, which were visualized with UV light.
Melting points were measured on an Electrothermal 9200
apparatus. The IR spectra were recorded on an FT-IR
In order to check the recyclability of the catalyst after
completion of the reaction, the reaction mixture was fil-
trated and the catalyst was recovered. Then the catalyst was
recycled five times without appreciable loss in catalytic
activity.
1
Magna 550 apparatus using KBr discs. H NMR and 13C
NMR spectra were recorded on a Bruker Avance DRX-400
instrument using TMS as the internal standard. The ele-
mental analyses (C, H, N) were obtained from a Carlo
ERBA Model EA 1108 analyzer. Microscopic morphology
of products was examined by SEM (LEO 1455VP).
A plausible mechanism for the synthesis of substituted
oxazines 5 is presented in Scheme 2. In the suggested
mechanism, we have proposed that an acid–base interaction
between FeCl3–SiO2 NPs and a lone pair of oxygen polar-
izes the C=O bond of DMF for the in situ formation of the
chloromethyleniminium intermediate A, which is respon-
sible for the formylation. The enolizable ketone moiety of
the amidoalkyl naphthol derivative 4 readily reacts with the
chloromethylenedimethylammonium chloride intermediate
at the active methylene position of 6 to yield the interme-
diate 7, which undergoes dehydrochlorination to form
Preparation of nano-silica-supported ferric chloride
In a 100-cm3 flask, 25 g nano silica gel and 2 g
FeCl3Á6H2O (8 % of the weight of nano-SiO2) were vig-
orously stirred under solvent-free conditions at room
temperature for 24 h to achieve homogeneous adsorption.
A pale yellowish-green product was obtained.
123

690
J. S. Ghomi, S. Zahedi
Scheme 2
SiO2
General procedure for the synthesis of amidoalkyl
naphthols 4a–4m
was crystallized from EtOH (15 %) to afford the pure
product. The products were characterized by comparison of
their physical data with those of known compounds unless
otherwise mentioned.
A mixture of 0.14 g b-naphthol (1 mmol), aldehyde
(1 mmol), 0.07 g acetamide (1.2 mmol), and 0.1 mg
FeCl3/SiO2 NPs (0.4 mol %) was finely ground and heated
with stirring at 110 °C in an oil bath, and the reaction was
monitored by TLC. After cooling, the reaction mixture was
dissolved in hot ethanol, and the mixture was stirred for
5 min. The reaction mixture was filtered, and the hetero-
geneous catalyst was recovered. Then the crude product
N-[(2-Hydroxynaphthalen-1-yl)(4-isopropylphenyl)-
methyl]acetamide (4h, C22H24NO2)
ꢀ
White solid; IR (KBr): m = 3,405, 3,168, 3,058, 1,633,
1,515, 1,438, 1,370, 1,330, 1,275, 1,168, 986, 816,
1
744 cm-1; H NMR (400 MHz, DMSO-d6): d = 1.14 (d,
6H), 1.95 (s, 3H), 2.81 (m, 1H), 7.06–7.11 (m, 5H), 7.19 (t,
J = 7.2 Hz, 1H), 7.27 (t, J = 7.6 Hz, 1H), 7.36 (t, 1H),
123

Eco-friendly synthesis of highly substituted functionalized oxazines
691
7.75 (d, 1H), 7.80 (d, 1H), 7.88 (d, 1H), 8.43 (d,
J = 8.4 Hz, 1H), 9.96 (s, 1H) ppm; 13C NMR (100 MHz,
DMSO-d6): d = 23.1, 24.4, 33.4, 48.3, 119.0, 119.4, 122.8,
123.0, 123.6, 126.3, 126.6, 126.7, 128.0, 128.9, 129.0,
129.5, 132.8, 140.3, 146.6, 153.5, 169.5 ppm.
cool to room temperature. The reaction mixture was fil-
tered, and the heterogeneous catalyst was recovered. The
filtrate was poured into crushed ice and refrigerated over-
night. The solution was neutralized with sodium acetate,
and the crude compound was extracted with dichloro-
methane (3 9 10 cm3) and washed with water (3 9
5 cm3). The organic layer was dried over anhydrous
sodium sulfate and concentrated under reduced pressure.
The crude product was purified through crystallization
from EtOH to afford the pure product.
N-[(2-Hydroxynaphthalen-1-yl)(4-hydroxyphenyl)-
methyl]acetamide (4k, C19H17NO3)
ꢀ
White solid; IR (KBr): m = 3,406, 3,180, 3,052, 1,616,
1,514, 1,438, 1,370, 1,330, 1,275, 1,168, 986, 813,
1
738 cm-1; H NMR (400 MHz, DMSO-d6): d = 1.97 (s,
3H), 7.04–7.09 (m, 5H), 7.19 (t, J = 7.2 Hz, 1H), 7.25 (t,
J = 7.6 Hz, 1H), 7.36 (t, 1H), 7.77 (d, 1H), 7.80 (d, 1H),
7.88 (d, 1H), 8.55 (d, J = 8.4 Hz, 1H), 9.20 (s, 1H), 9.87
(s, 1H) ppm; 13C NMR (100 MHz, DMSO-d6): d = 23.4,
48.5, 119.3, 120.1, 122.8, 123.0, 123.6, 126.3, 126.6,
126.7, 128.0, 128.9, 129.0, 129.5, 132.8, 140.3, 146.8,
153.2, 168.9 ppm.
(1,2-Dihydro-1-phenyl-3H-naphtho[1,2-e][1,3]oxazine-3-
ylidene)malonaldehyde (5a, C21H15NO3)
ꢀ
Yellow solid; IR (KBr): m = 3,398, 1,629, 1,515, 1,453,
1
1,221, 828 cm-1; H NMR (400 MHz, CDCl3): d = 6.24
(s, 1H), 7.13–7.15 (d, 2H), 7.17–7.21 (d, 2H), 7.48–7.49 (t,
3H), 7.76 (t, 2H), 7.90 (d, 1H), 7.97 (d, 1H), 10.04 (br s,
2H, CHO), 12.33 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 50.6, 101.1, 113.6, 118.3, 123.2, 124.7,
127.3, 128.8, 129.6, 130.4, 131.7, 132.9, 134.5, 143.6,
144.9, 148.4, 162.3, 186.9 ppm.
N-[(2,4-Dimethoxyphenyl)(2-hydroxynaphthalen-1-yl)-
methyl]acetamide (4l, C21H21NO4)
ꢀ
Yellow solid; IR (KBr): m = 3,406, 3,139, 1,646, 1,521,
1,506, 1,442, 1,400, 1,374, 1,329, 1,264, 1,242, 1,091,
[1,2-Dihydro-1-(4-nitrophenyl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5b, C21H14N2O5)
1
1,068, 818, 764, 659 cm-1; H NMR (400 MHz, DMSO-
d6): d = 1.90 (s, 3H), 3.72 (s, 6H), 6.89–7.01 (m, 2H), 7.17
(d, J = 8.4 Hz, 1H), 7.29 (t, J = 7.2 Hz, 1H), 7.33-7.39
(m, 2H), 7.46 (d, J = 8.4 Hz, 1H), 7.74–7.79 (m, 3H), 8.55
(d, J = 7.6 Hz, 1H), 9.98 (s, 1H) ppm; 13C NMR
(100 MHz, DMSO-d6): d = 23.3, 48.7, 55.2, 55.9, 110.4,
118.6, 118.8, 123.2, 126.9, 128.5, 129.1, 129.5, 129.7,
130.5, 131.6, 132.8, 144.9, 149.3, 153.7, 153.9, 170.2 ppm.
ꢀ
Yellow solid; IR (KBr): m = 3,408, 1,632, 1,515, 1,453,
1
1,221, 828 cm-1; H NMR (400 MHz, CDCl3): d = 6.23
(s, 1H), 7.10–7.14 (d, 2H), 7.17–7.21 (d, 2H), 7.46–7.49 (t,
3H), 7.61 (d, 1H), 7.88 (d, 1H), 7.96 (d, 1H), 10.02 (br s,
2H, CHO), 12.25 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 50.3, 101.3, 113.4, 117.9, 123.3, 125.7,
127.3, 128.5, 128.9, 129.6, 130.4, 131.7, 131.8, 132.9,
134.5, 143.6, 144.9, 148.4, 162.6, 187.0 ppm.
N-[(2-Hydroxynaphthalen-1-yl)(naphthalen-1-yl)-
methyl]acetamide (4m, C23H19NO2)
[1,2-Dihydro-1-(2-nitrophenyl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5c, C21H14N2O5)
Yellow solid; IR (KBr): ꢀm = 3,399, 1,630, 1,515, 1,453,
ꢀ
White solid; IR (KBr): m = 3,412, 3,173, 3,060, 1,642,
1,572, 1,514, 1,437, 1,400, 1,374, 1,332, 1,274, 1,224,
1
1,172, 932, 813, 745 cm-1; H NMR (400 MHz, DMSO-
1,221, 825 cm-1; H NMR (400 MHz, CDCl3): d = 6.23
1
d6): d = 1.90 (s, 3H), 7.22–7.29 (m, 3H), 7.39–7.44 (m,
4H), 7.61 (d, 1H), 7.70–7.80 (m, 3H), 7.91–8.03 (d, 3H),
8.70 (d, 1H), 10.01 (s, 1H) ppm; 13C NMR (100 MHz,
DMSO-d6): d = 22.9, 47.4, 117.6, 118.7, 119.3, 122.8,
123.5, 123.9, 125.5, 125.7, 125.9, 126.5, 126.7, 127.9,
129.0, 129.2, 129.7, 131.5, 133.3, 134.0, 137.8, 153.8,
168.9 ppm.
(s, 1H), 7.10–7.14 (d, 2H), 7.17–7.21 (t, 2H), 7.46–7.49 (t,
3H), 7.61 (d, 1H), 7.88 (d, 1H), 7.96 (d, 1H), 10.01 (br s,
2H, CHO), 12.26 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 48.9, 101.1, 113.7, 118.4, 123.3, 125.7,
127.3, 128.5, 128.9, 129.6, 130.4, 131.7, 131.8, 132.9,
134.5, 143.2, 144.5, 148.2, 162.3, 186.8 ppm.
[1-(4-Chlorophenyl)-1,2-dihydro-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5d, C21H14ClNO3)
General procedure for the synthesis of 1,3-oxazines
5a–5m
ꢀ
Yellow solid; IR (KBr): m = 3,406, 1,627, 1,515, 1,453,
1
1,221, 831 cm-1; H NMR (400 MHz, CDCl3): d = 6.21
(s, 1H), 7.12–7.14 (d, 2H), 7.19–7.25 (d, 2H), 7.46–7.49 (t,
3H), 7.61 (d, 1H), 7.88 (d, 1H), 7.96 (d, 1H), 10.01 (br s,
2H, CHO), 12.28 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 50.4, 101.1, 113.4, 117.9, 123.3, 125.7,
127.3, 128.5, 128.9, 129.6, 130.4, 131.7, 131.8, 132.9,
134.5, 143.6, 144.9, 148.4, 163.1, 186.7 ppm.
To a solution of acetamidonaphthol 4 (1 mmol) and 0.1 mg
FeCl3/SiO2 NPs dissolved in DMF (1.2 equiv.), POCl3 (0.8
eqiuvalent) was added slowly dropwise (15 min) at 0 °C,
and the reaction mixture was allowed to reach room tem-
perature. Then the reaction mixture was stirred at 80 °C for
30 min. After completion of the reaction, it was allowed to
123

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J. S. Ghomi, S. Zahedi
[1-(2,4-Dichlorophenyl)-1,2-dihydro-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5e, C21H13Cl2NO3)
[1,2-Dihydro-1-(4-hydroxyphenyl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5k, C21H15NO4)
ꢀ
ꢀ
Yellow solid; IR (KBr): m = 3,409, 1,620, 1,510, 1,449,
Yellow solid; IR (KBr): m = 3,405, 1,626, 1,514, 1,449,
1
1
1,220, 826 cm-1; H NMR (400 MHz, CDCl3): d = 6.22
1,220, 822 cm-1; H NMR (400 MHz, CDCl3): d = 6.23
(s, 1H), 7.19–7.25 (d, 2H), 7.49–7.62 (d, 2H), 7.65–7.70 (d,
2H), 7.89–7.93 (d, 2H), 8.11 (s, 1H), 10.03 (br s, 2H,
CHO), 12.28 (s, 1H) ppm; 13C NMR (100 MHz, CDCl3):
d = 50.3, 101.3, 113.4, 117.2, 123.1, 124.3, 126.8, 128.8,
128.9, 129.6, 130.1, 131.7, 131.8, 131.9, 134.5, 143.0,
144.8, 148.6, 162.1, 186.7 ppm.
(s, 1H), 7.18–7.24 (d, 2H), 7.47–7.63 (d, 2H), 7.63–7.71 (d,
2H), 7.89–7.93 (d, 2H), 8.11 (s, 1H), 9.45 (s, 1H), 10.01 (br
s, 2H, CHO), 12.29 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 50.3, 101.3, 113.4, 117.2, 123.1, 124.3,
126.8, 128.8, 128.9, 129.6, 130.1, 131.7, 131.8, 131.9,
134.5, 143.0, 144.8, 148.6, 162.1, 186.7 ppm.
[1,2-Dihydro-1-(4-methylphenyl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5f, C22H17NO3)
[1-(2,4-Dimethoxyphenyl)-1,2-dihydro-3H-naphtho[1,2-e]-
[1,3]oxazine-3-ylidene]malonaldehyde (5l, C23H19NO5)
ꢀ
ꢀ
Yellow solid; IR (KBr): m = 3,408, 1,628, 1,515, 1,453,
Yellow solid; IR (KBr): m = 3,397, 1,628, 1,515, 1,449,
1
1
1,219, 821 cm-1; H NMR (400 MHz, CDCl3): d = 2.30
1,220, 821 cm-1; H NMR (400 MHz, CDCl3): d = 3.72
(s, 3H), 6.20 (s, 1H), 7.10–7.13 (d, 2H), 7.15–7.20 (d, 2H),
7.42–7.48 (t, 3H), 7.58 (d, 1H), 7.84 (d, 1H), 7.97 (d, 1H),
10.03 (br s, 2H, CHO), 12.26 (s, 1H) ppm; 13C NMR
(100 MHz, CDCl3): d = 23.3, 50.2, 101.1, 113.4, 117.9,
123.3, 125.7, 127.3, 128.5, 128.9, 129.6, 130.4, 131.7,
131.8, 132.9, 134.5, 142.9, 144.4, 147.8, 162.2, 186.8 ppm.
(s, 6H), 6.22 (s, 1H), 7.19–7.25 (d, 2H), 7.49–7.62 (d, 2H),
7.65–7.70 (d, 2H), 7.89–7.93 (d, 2H), 8.11 (s, 1H), 10.03
(br s, 2H, CHO), 12.28 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 50.1, 53.5, 53.6, 101.2, 113.4, 117.2, 123.1,
124.3, 126.8, 128.8, 128.9, 129.6, 130.2, 131.7, 131.8,
131.9, 134.5, 143.0, 144.8, 148.4, 163.6, 186.9 ppm.
[1,2-Dihydro-1-(4-methoxyphenyl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5g, C22H17NO4)
[1,2-Dihydro-1-(naphthalen-1-yl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5m, C25H17NO3)
ꢀ
ꢀ
Yellow solid; IR (KBr): m = 3,403, 1,624, 1,513, 1,449,
Yellow solid; IR (KBr): m = 3,404, 1,623, 1,510, 1,449,
1
1,220, 819 cm-1; H NMR (400 MHz, CDCl3): d = 3.48
1,220, 826 cm-1 1H NMR (400 MHz, CDCl3):
;
(s, 3H), 6.21 (s, 1H), 7.18-7.26 (d, 2H), 7.45-7.60 (d, 2H),
7.63-7.72 (d, 2H), 7.87–7.91 (d, 2H), 8.08 (s, 1H), 10.02
(br s, 2H, CHO), 12.24 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 33.5, 50.1, 101.1, 113.4, 117.2, 123.1, 124.3,
126.8, 128.8, 128.9, 129.6, 130.4, 131.7, 131.8, 131.9,
134.2, 143.5, 145.4, 148.4, 162.2, 187.2 ppm.
d = 7.20–7.27 (m, 3H), 7.36–7.42 (m, 4H), 7.61 (d, 1H),
7.70–7.82 (m, 3H), 7.89–8.01 (d, 3H), 8.77(d, 1H), 10.01
(br s, 2H, CHO), 12.27 (s, 1H) ppm; 13C NMR (100 MHz,
DMSO-d6): d = 53.4, 101.1, 118.7, 119.3, 122.8, 123.5,
123.9, 125.5, 125.7, 125.9, 126.5, 126.7, 127.9, 129.0,
129.2, 129.7, 131.5, 133.3, 134.0, 137.8, 144.8, 148.4,
163.6, 186.9 ppm.
[1,2-Dihydro-1-(4-isopropylphenyl)-3H-naphtho[1,2-e][1,3]-
oxazine-3-ylidene]malonaldehyde (5h, C24H21NO3)
Acknowledgments The authors are grateful to Islamic Azad Uni-
versity, Qom Branch, for financial support of this work.
ꢀ
Yellow solid; IR (KBr): m = 3,407, 1,619, 1,513, 1,454,
1
1,220, 834 cm-1; H NMR (400 MHz, CDCl3): d = 1.19
(d, 6H), 2.84 (m, 1H), 6.20 (s, 1H), 7.19–7.25 (d, 3H),
7.49–7.62 (t, 3H), 7.89–7.93 (t, 2H), 8.12 (m, 2H), 10.02
(br s, 2H, CHO), 12.26 (s, 1H) ppm; 13C NMR (100 MHz,
CDCl3): d = 23.2, 33.5, 50.3, 101.3, 113.4, 117.2, 123.1,
124.3, 126.8, 128.8, 128.9, 129.6, 130.1, 131.7, 131.8,
131.9, 134.5, 143.0, 144.8, 148.6, 162.1, 186.7 ppm.
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