Synthesis of 2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4-e][1,3]oxazin-5-one via a three-component condensation

Article abstract of DOI:10.1080/10426507.2020.1858082

The reaction between 4-hydroxy-6-methyl-2H-pyran-2-one and aroyl chlorides with potassium selenocyanate in the presence of catalytic amounts of N-methylimidazole under solvent-free conditions provided a simple and efficient one-pot route for the synthesis

Full text of DOI:10.1080/10426507.2020.1858082

Phosphorus, Sulfur, and Silicon and the Related Elements
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Synthesis of 2-aryl-7-methyl-4-selenoxo-4H-
pyrano[3,4-e][1,3]oxazin-5-one via a three-
component condensation
Amir Rashidi , Mohammad H. Mosslemin & Alireza Hassanabadi
To cite this article: Amir Rashidi , Mohammad H. Mosslemin & Alireza Hassanabadi (2020):
Synthesis of 2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4-e][1,3]oxazin-5-one via a three-
component condensation, Phosphorus, Sulfur, and Silicon and the Related Elements, DOI:
10.1080/10426507.2020.1858082
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PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
https://doi.org/10.1080/10426507.2020.1858082
Synthesis of 2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4-e][1,3]oxazin-5-one
via a three-component condensation
Amir Rashidia, Mohammad H. Mosslemina, and Alireza Hassanabadib
b
aDepartment of Chemistry, Yazd Branch, Islamic Azad University, Yazd, Iran; Department of Chemistry, Zahedan Branch, Islamic Azad
University, Zahedan, Iran
ABSTRACT
ARTICLE HISTORY
Received 28 September 2020
Accepted 26 November 2020
The reaction between 4-hydroxy-6-methyl-2H-pyran-2-one and aroyl chlorides with potassium sele-
nocyanate in the presence of catalytic amounts of N-methylimidazole under solvent-free conditions
provided a simple and efficient one-pot route for the synthesis of 2-aryl-7-methyl-4-selenoxo-4H-
pyrano[3,4-e][1,3]oxazin-5-one. The reaction is characterized by mild conditions, short reaction time
easy work-up, high yields of biological active products, and does not involve any hazardous solvent
and tolerance to various functional groups.
KEYWORDS
4-Hydroxy-6-methyl-2H-
pyran-2-one; aroyl chlorides;
potassium selenocyanate;
N-methylimidazole; pyr-
ano[3,4-e][1,3]oxazines
GRAPHICAL ABSTRACT
Introduction
functions.[21–25] The first synthesis of acyl isoselenocyanates,
which were generated by the reaction of acyl chlorides and
potassium selenocyanate, has been described by Douglas.[26]
Recently, a few synthesis of heterocycles from acyl isoseleno-
cyanates were reported.[27–29] Herein, we describe a synthesis
of 2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4-e][1,3]oxazin-5-
one using a reported method.[27]
Multi-component reactions have been receiving great atten-
tion from chemists because they can be widely employed for
the rapid assembly of arrays with high molecular diver-
sity.[1–4] Derivatives of 1,3-oxazine play a significant role the
theoretical organic chemistry[5] and biologically active com-
pounds.[6] They show interesting interactions and can be
used as chemotherapy agents.[7] Dihydro-1,3-oxazine skele-
tons can be formed in proteins as they are converted into
polypeptides The thio derivatives of pyrano-1,3-benzoxazine
have also shown anti-inflammatory and antipyretic proper-
ties.[8,9] Synthesis of 1,3-oxazine derivatives has already been
reported[10–19] and this synthesis used a procedure first
described by Khalilzadeh et al.[20] in which they synthesized a
series of arylated bicyclic and tricyclic thioheterocycles via the
N-methylimidazole-catalyzed reaction of phenol and 1- and
2-naphthols with a series of aroyl chlorides and ammonium
thiocyanate. Although many useful and reliable methods for
preparation of 1,3-oxazines have been reported in the litera-
ture,[10–19] many of these procedures have significant draw-
backs such as low yields of the products, long reaction times,
and harsh reaction conditions. Thus, new routes for the syn-
thesis of these molecules have attracted considerable attention
in search for a rapid entry to these heterocycles. The current
interest in selenium-containing organic compounds stems
Results and discussion
Using reaction conditions similar to those previously
described,[27] one-pot, three-component reaction between 4-
hydroxy-6-methyl-2H-pyran-2-one 1 and aroyl chlorides 2 with
potassium selenocyanate 3 in the presence of catalytic amounts
of N-methylimidazole under solvent-free conditions afford the
2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4-e][1,3]oxazin-5-one
4 in nearly quantitative yields (Scheme 1).
To study the scope of the reaction, a series of aroyl chlor-
ides were applied. The results are shown in Table 1. In all
cases, aroyl chloride substituted with either electron-donat-
ing or electron-withdrawing groups underwent the reaction
smoothly and gave products in excellent yields.
To find out the optimum quantity of N-methylimidazole, the
reaction of potassium selenocyanate and 4-nitro benzoylchlor-
ides with 4-hydroxy-6-methyl-2H-pyran-2-one was carried out
from
their
remarkable
synthetic
and
biological under solvent-free conditions using different quantities of N-
CONTACT Mohammad H. Mosslemin
mhmosslemin@gmail.com
Department of Chemistry, Yazd Branch, Islamic Azad University, Yazd, Iran.
Supplemental data for this article is available online at https://doi.org/10.1080/10426507.2020.1858082.
ß 2020 Taylor & Francis Group, LLC

2
A. RASHIDI ET AL.
Scheme 1. Three-component condensation of 4-hydroxy-6-methyl-2H-pyran-2-one, aroyl chlorides and potassium selenocyanate.
e][1,3]oxazin-5-one by one-pot condensation reaction of
between 4-hydroxy-6-methyl-2H-pyran-2-one and aroyl
chlorides with potassium selenocyanate in the presence of
catalytic amounts of N-methylimidazole under solvent-free
conditions. The present procedure has the advantages such
as mild reaction conditions, short reaction time, easy work-
up, high yields of biological active products.
Table 1. Yields of
e][1,3]oxazin-5-one (4) prepared from 4-hydroxy-6-methyl-2H-pyran-2-one (1),
aroyl chlorides (2) and potassium selenocyanate (3) (Scheme 1).
a series of 2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4-
Entry
Ar
Product
Yield (%)a
m.p. (ꢁC)
1
2
3
4
5
6
4-NO2C6H4
4-ClC6H4
4-BrC6H4
3-NO2C6H4
C6H5
4a
4b
4c
4d
4e
4f
91
83
81
92
76
73
125–127
154–156
138–140
113–115
96–98
4-CH3C6H4
101–103
aYields refer to the pure isolated products.
Experimental
Table 2. Optimization amount of N-methylimidazole on the reaction of con-
densation of potassium selenocyanate and aroyl chlorides with 4-hydroxy-6-
methyl-2H-pyran-2-one.
Melting points were determined with an Electrothermal 9100
apparatus. Elemental analysis were performed using a Heraeus
CHN-O-Rapid analyzer. Mass spectra were recorded on a
FINNIGAN-MAT 8430 mass spectrometer operating at an
ionization potential of 70 eV. IR spectra of selected com-
pounds were recorded on a Shimadzu IR-470 spectrometer in
KBr disks. NMR spectra were obtained on a Bruker DRX-400
Avance spectrometer (1H NMR at 400 MHz, 13C NMR at
100 MHz, and 77Se NMR at 76.2 MHz) in DMSO-d6 using
TMS as internal standard. The chemicals used in this work
were purchased from Fluka (Buchs, Switzerland) and were
used without further purification.
Entry
Catalyst (mol%)
Time (min)
Yield (%)a
1
2
3
4
5
3
5
7
10
12
90
70
60
40
40
45
60
70
91
91
aIsolated yield.
methylimidazole (Table 2). N-methylimidazole of 10% gave an
excellent yield in 40 min (Table 2, entry 4).
The structures of compounds 4a–f were deduced from their
high-field 1H NMR, 13C NMR, IR spectral data, elemental ana-
lysis, and mass spectra. The mass spectra of compounds 4a–f
are fairly similar and display molecular ion peaks. For example,
the mass spectrum of compound 4a showing a molecular ion
peak at m/z 363 confirmed that compound 4a is a condensation
product of 4-hydroxy-6-methyl-2H-pyran-2-one, 4-nitroben-
zoyl chloride, and potassium selenocyanate. The 1H NMR spec-
trum of 4a exhibited two sharp singlets readily recognized as
arising from methyl (d ¼ 2.01 ppm), and methine
Caution! All workers must be thoroughly trained on the
use of selenium-containing compounds, and they must wear
appropriate personal safety gear. All of the reactions involv-
ing selenium-containing compounds must be carried out in
a well-ventilated hood. The Supporting Information contains
1
sample H, 13C, and 77Se NMR spectra of the products 4a–f
(Supporting Information Figures S1–S18).
(d ¼ 5.82ppm)
protons,
along
with
multiplets
(d ¼ 7.97–8.08 ppm) for aromatic protons. The 13C NMR spec-
trum of compound 4a shows 12 distinct signals consistent with
the proposed structure. The C ¼ Se, C ¼ O, and C ¼ N groups
resonance in 13C NMR spectra of 4a appears at 193.8, 163.1,
and 161.7ppm respectively. The selenone 13C resonances of
compounds 4 were observed at 192.5–164.6 ppm.[27,30]
General procedure
To potassium selenocyanate (1 mmol) in a 10 mL flask at r.t.
was added Aroyl chloride (1 mmol) via syringe. The reaction
mixture was stirred in a water bath at about 90 ꢁC for
The 77Se NMR of compound 4a consisted of a singlet at
d ¼ 745 ppm. The IR spectrum of compound 4a also sup-
ported the suggested structure exhibiting strong absorption
bands at 1711 cmꢀ1 for the C ¼ O and 1280 cmꢀ1 for the
C ¼ Se groups. The mechanism of the reaction is probably
similar to that published by Yavari et al.[27] A tentative
mechanism for this transformation is proposed in Scheme 2.
10 min.
Then,
4-hydroxy-6-methyl-2H-pyran-2-one
(1 mmol) was added at this temperature. The reaction mix-
ture was allowed to cool to room temperature. Finally, N-
methylimidazole (0.082 g; 1 mmol) was added via syringe.
The resulting mixture was stirred at r.t. for 40 min. The pro-
gress of the reaction was monitored by TLC. After comple-
tion of the reaction, the residue was separated by silica gel
In conclusion, here we reported a facile and efficient one- (Merck 230–240 mesh) column chromatography using
pot synthesis of 2-aryl-7-methyl-4-selenoxo-4H-pyrano[3,4- hexane–ethyl acetate mixture (3:1) as eluent.

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
3
Scheme 2. Proposed mechanism for 4.
2-(4-Nitrophenyl)-7-methyl-4-selenoxo-4H-pyrano[3,4-
e][1,3]oxazin-5-one (4a)
(C ¼ Se); 77Se NMR: d ¼ 730; MS m/z (%): 397 (6); Anal.
Calcd. for C14H8BrNO3Se: C, 42.35; H, 2.03; N, 3.53%.
Found: C, 42.41; H, 2.10; N, 3.62.
Brown powder; m.p. 125–127 ꢁC; IR (KBr) (ꢀmax cmꢀ1):
1
1711, 1668, 1552, 1344, 1280, 1087; H NMR: d 2.01 (3H, s,
3
CH3), 5.82 (1H, s, ¼CH), 7.97 (2H, d, JHH ¼ 8 Hz, 2CH of
2-(3-Nitrophenyl)-7-methyl-4-selenoxo-4H-pyrano[3,4-
e][1,3]oxazin-5-one (4d)
3
C6H4NO2), 8.08 (2H, d, JHH ¼ 8 Hz, 2CH of C6H4NO2);
13C NMR: d 19.3 (CH3), 88.0, 100.3, 123.1, 128.7, 130.2,
132.6, 135.3, 148.7, 161.7 (C ¼ N), 163.1 (C ¼ O), and 193.8
(C ¼ Se); 77Se NMR: d ¼ 745; MS m/z (%): 363 (12); Anal.
Calcd for C14H8N2O5Se: C, 46.30; H, 2.22; N, 7.71%. Found:
C, 46.37; H, 2.30; N, 7.82.
Brown powder; m.p. 113–115 ꢁC; IR (KBr) (ꢀmax cmꢀ1):
1
1716, 1669, 1564, 1347, 1285, 1090; H NMR: d 2.43 (3H, s,
CH3), 5.62 (1H, s, ¼CH), 7.14–8.30 (4H, m, 4CH of
C6H4NO2); 13C NMR: d 19.3 (CH3), 87.9, 100.8, 122.8,
129.8, 130.4, 130.8, 132.6, 135.7, 136.5, 149.1, 161.4 (C ¼ N),
163.7 (C ¼ O), and 194.6 (C ¼ Se); 77Se NMR: d ¼ 743; MS
m/z (%): 363 (9); Anal. Calcd for C14H8N2O5Se: C, 46.30; H,
2.22; N, 7.71%. Found: C, 46.40; H, 2.32; N, 7.80.
2-(4-Chlorophenyl)-7-methyl-4-selenoxo-4H-pyrano[3,4-
e][1,3]oxazin-5-one (4 b)
Brown powder; m.p. 154–156 ꢁC; IR (KBr) (ꢀmax cmꢀ1):
1
1719, 1664, 1618, 1255, 1087; H NMR: d 2.10 (3H, s, CH3),
7-Methyl-2-Phenyl-4-selenoxo-4H-pyrano[3,4-e][1,3]
oxazin-5-one (4e)
3
5.95 (1H, s, ¼CH), 7.45 (2H, d, JHH ¼ 8 Hz, 2CH of
C6H4Cl), 7.85 (2H, d, JHH ¼ 8 Hz, 2CH of C6H4Cl); 13C
3
Brown powder; m.p. 96–98 ꢁC; IR (KBr) (ꢀmax cmꢀ1): 1716,
NMR: d 19.4 (CH3), 88.0, 100.3, 122.9, 128.2, 129.3, 130.4,
135.5, 145.9, 162.1 (C ¼ N), 164.3 (C ¼ O), and 193.5
(C ¼ Se); 77Se NMR: d ¼ 733; MS m/z (%): 352 (8); Anal.
Calcd. for C14H8ClNO3Se: C, 47.69; H, 2.29; N, 3.97%.
Found: C, 47.75; H, 2.37; N, 4.05.
1
1658, 1627, 1257, 1041; H NMR: d 2.24 (3H, s, CH3), 5.95
(1H, s, ¼CH), 7.47–7.77 (5H, m, 5CH of C6H5); 13C NMR:
d 19.9 (CH3), 89.8, 101.5, 127.4, 127.8, 128.6, 129.2, 132.3,
133.8, 161.8 (C ¼ N), 165.7 (C ¼ O), and 194.0 (C ¼ Se); 77Se
NMR: d ¼ 705; MS (m/z, %): 318 (5); Anal. Calcd. for
C14H9NO3Se: C, 52.85; H, 2.85; N, 4.40%. Found: C, 52.95;
H, 2.93; N, 4.46.
2-(4-Bromophenyl)-7-methyl-4-selenoxo-4H-pyrano[3,4-
e][1,3]oxazin-5-one (4c)
Brown powder; m.p. 138–140 ꢁC; IR (KBr) (ꢀmax cmꢀ1):
7-Methyl-4-selenoxo-2-p-tolyl-4H-pyrano[3,4-e][1,3]
oxazin-5-one (4f)
1
1718, 1661, 1615, 1250, 1053; H NMR: d 2.31(3H, s, CH3),
3
5.68 (1H, s, ¼CH), 7.05 (2H, d, JHH ¼ 8 Hz, 2CH of
Brown powder; m.p. 101–103 ꢁC; IR (KBr) (ꢀmax cmꢀ1):
3
C6H4Br), 7.41 (2H, d, JHH ¼ 8 Hz, 2CH of C6H4Br); 13C
17,013, 1670, 1612, 1267, 1080; 1H NMR: d 2.06 (3H, s,
NMR: d 19.3 (CH3), 88.1, 99.7, 123.1, 128.3, 129.3, 130.1,
132.6, 141.6, 161.8 (C ¼ N), 165.3 (C ¼ O), and 193.9 CH3), 2.45 (3H, s, CH3), 5.61 (1H, s, ¼CH), 7.06 (2H, d,

4
A. RASHIDI ET AL.
3
3JHH ¼ 8 Hz, 2CH of C6H4CH3), 7.45 (2H, d, JHH ¼ 8 Hz,
2CH of C6H4CH3); 13C NMR: d 19.2 (CH3), 21.9 (CH3),
89.2, 101.5, 126.9, 129.1, 129.5, 134.3, 135.5, 144.4, 161.3
(C ¼ N), 163.8 (C ¼ O), and 192.5 (C ¼ Se); 77Se NMR:
d ¼ 713; MS (m/z, %): 332 (6); Anal. Calcd. for
C15H11NO3Se: C, 54.23; H, 3.34; N, 4.22%. Found: C, 54.30;
H, 3.41; N, 4.31.
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