Reaction of 2-imino-2H-chromene-3-carboxamide with phosphorus sulfides: Synthesis of novel 2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diaza-phosphinines

Article abstract of DOI:10.1080/10426507.2018.1487439

Novel 2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diazaphosphinines are obtained in a simple one-pot procedure via treatment of 2-imino-2H-chromene-3-carboxamide with various phosphorus sulfides. Possible reaction mechanisms are proposed. The structure

Full text of DOI:10.1080/10426507.2018.1487439

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: http://www.tandfonline.com/loi/gpss20
Reaction of 2-imino-2H-chromene-3-carboxamide
with phosphorus sulfides: Synthesis of novel
2-sulfido-2,3-dihydro-4H-chromeno[2,3-d]
[1,3,2]diaza-phosphinines.
Tarik E. Ali, Hafez M. El-Shaaer, Mohamed M. Hassan & Noha M. Hassanin
To cite this article: Tarik E. Ali, Hafez M. El-Shaaer, Mohamed M. Hassan & Noha M. Hassanin
(2018): Reaction of 2-imino-2H-chromene-3-carboxamide with phosphorus sulfides: Synthesis of
novel 2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diaza-phosphinines., Phosphorus, Sulfur, and
Silicon and the Related Elements, DOI: 10.1080/10426507.2018.1487439
To link to this article: https://doi.org/10.1080/10426507.2018.1487439
Accepted author version posted online: 26
Jul 2018.
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1
Reaction of 2-imino-2H-chromene-3-carboxamide with phosphorus sulfides:
Synthesis
of
novel
2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diaza-
phosphinines.
1
1
1
1,*
Tarik E. Ali , Hafez M. El-Shaaer , Mohamed M. Hassan , Noha M. Hassanin
1
Department of Chemistry, Faculty of Education, Ain Shams University, Roxy, Cairo, Egypt
Corresponding Author: Noha M. Hassanin noha.hassanin2020@yahoo.com,
*
noha_mohamed@edu.asu.edu.eg
Abstract
Novel
2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diazaphosphinines
are
obtained in a simple one-pot procedure via treatment of 2-imino-2H-chromene-3-
carboxamide with various phosphorus sulfides. Possible reaction mechanisms are
proposed. The structure of the obtained products is confirmed by elemental analyses
and spectral tools.
Graphic Abstract
Keywords: Chromene, 1,3,2-diazaphosphinine, phosphorus sulfides
INTRODUCTION
Fused polycyclic chromene compounds have received much synthetic
1
,2
3
attention because of their important biological properties such as antioxidant,
4
5
anticancer, and antimicrobial activity. On the other hand, phosphorus compounds

2
continue to attract a great interest because of the diversity of structures and
pharmacological activities, especially when they are associated with different
6
7
8
heterocycles. For example, they were used as antitumor, antineoplastic, anti-
9
10
inflammatory and biodegradable insecticide agents. Considering the above facts
and our research program on the development of new biologically active heterocyclic
1
1-14
organophosphorus compounds,
we herein report the synthesis of some novel
chromeno[2,3-d][1,3,2]diazaphinine-2-sulfides via treatment of 2-imino-2H-
chromene-3-carboxamide (1) with various phosphorus sulfides.
RESULTS AND DISCUSSION
The starting material 2-imino-2H-chromene-3-carboxamide (1) was prepared
according to the reported method by a Knovenagel condensation and intramolecular
cyclization of salicylaldehyde with cyanoacetamide in absolute ethanol containing a
1
5
few drops of triethylamine (Scheme 1).
O
O
C H O
E tO H , E t N
3
N H2
+
N H2
O H
8 5 %
C N
O
N H
1
Scheme 1.
The presence of two active nucleophilic and two electrophilic centers in the
molecule of 2-imino-2H-chromene-3-carboxamide (1) provides alternative
opportunities in the direction of the reaction with electrophilic and nucleophilic
phosphorus reagents such as phosphorus sulfides. Its synthetic precursor opens wide
opportunities for the use of chromene systems in the synthesis of diverse fused
phosphorus heterocyclic compounds.
Phosphorus decasulfide and Lawesson's reagent (LR) have been used as
versatile reagents for thionation processes and the construction of phosphorus and

3
1
6,17
sulfur heterocycles.
Also, a series of hetaryl-substituted carbinols were converted
1
8
into the corresponding thiols and sulfides by treatment with LR. In addition, some
secondary alcohols bearing ferrocenyl and a hetaryl substituent reacted with LR to
give unexpected tetra-substituted ethane or disubstituted methane derivatives with no
1
9
sulfur atom in the molecule.
Thus, reaction of 1 with phosphorus decasulfide in dry dioxane under reflux for 7
hours afforded the unexpected 2-sulfanyl-2-sulfido-2,3-dihydro-4H-chromeno[2,3-
d][1,3,2]diazaphinin-4-one (2A) which apparently exists in another enol form 2B
according to its spectral data (Scheme 2). Although P S is an effective reagent for
4
10
2
0
the thionation of amides, its reaction with 1 did not result in any thionated product.
This may be due to the high reactivity of NH functional groups towards P S which
4
10
2
1
lead to cyclization instead of thionation reactions. Also, we observed the formation
of an interesting hydrolysis product, the known 2-oxo-2H-chromene-3-carboxamide
2
2
(
3), obtained as yellow crystal needles, which was formed during the purification of
compound 2 by a crystallization process from hot polar solvent such as DMF. The
structure of 2 was proved by spectroscopic means. Its IR spectrum indicated the

1
presence of OH, NH and C=O functions with bands at 3361, 3200 and 1710 cm ,
1
respectively. Also, its H NMR spectrum revealed D O-exchangeable signals at δ 6.79
2
1
3
(
SH), 7.89 (NH), 8.05 (OH) and 5-H proton at δ 8.35 and 8.85 ppm. Moreover, its C
NMR spectrum showed the specific signals of C-5 and C-4 at δ 146.4, 148.3 and
60.7, 163.0 ppm, respectively, thus supporting the existence of this product in two
1
tautomeric forms. Furthermore, its mass spectrum exhibited the expected molecular
+
ion peak at m/z 282 (M , 5%).

4
O
O
S
P
+
N H2
P 4 S 1 0
N
H
S
dio xa ne
O
N H
O
N H
A
1
9
5 %
O
O
O
6
5
4
4 a
3
5
a
7
8
D M F
N H
P
N H2
2
8
0 %
S H
9
a
1 0 a
O
N
1
O
9
S
2
A
3
O H
N
P
S H
O
N
S
P
2
B
S
S
P
S
P
S
P
S
+
S
S
S
+
2
P 4 S 1 0
S
S
S
2
P
S
P
+
2
P
+
S
S
S
S
S
S
Scheme 2.
When the above reaction was carried out via reaction of 1 with the P S -
4
10
pyridine
complex
in
dry pyridine,
the
pyridinium
chromeno[2,3-
d][1,3,2]diazaphosphinine sulfide 4 was isolated as the sole product without any
traces of thionated compounds (Scheme 3). Also, the sulfide 4 was obtained with
higher yield by warming compound 2 in dry pyridine for 15 minutes. In the same
manner, 4 underwent hydrolysis into the corresponding coumarin 3 through heating in
DMF. The IR spectrum of 4 exhibited carbonyl bands at 1699 cm1 and two NH

1
1
groups at 3291 and 3149 cm . Its H NMR spectrum displayed the aromatic protons
1
3
of the pyridine ring and two D O-exchangeable signals for NH protons, while its C
2
NMR revealed three characteristic signals for the pyridine ring at δ 125.6 (C ), 133.9
β,β'
(
C ) and 135.9 (C ) ppm. The suggested structure of compound 4 was further
 α,α'
+
corroborated by the molecular ion peak at m/z 361 (M , 2%) in its mass spectrum.

5
O
O
S
P 4 S 1 0 - P yrid in e C o m p le x
+
N H2
N
H
P
S
N
O
N H
O
N H
1
B
3
0 %
O
H
N
+
P yrid in e , 6 0 o
C
N H
2
P
5
0 %
S
O
N
S
4
6
5 % D M F
O
O
P 4 S 1 0 - P yrid in e C o m p le x
S
P
S
S
P
S
N
+
S
N
+
N H2
O
3
Scheme 3.
Next, treatment of compound 1 with Lawesson's reagent in dry dioxan, led to 2-
4-methoxyphenyl)-4-oxo-2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diaza-
(
phosphinine (5) (Scheme 4). The formation of a diazaphosphinine ring can be
explained on the basis of nucleophilic attack of the NH group at the phosphorus atom
2
of LR, followed by intramolecular cyclization via removal of H S affording the
2
desired fused triheterocyclic system (Scheme 4). The mass spectrum of 5 showed its
+
1
molecular ion peak at m/z 356 (M , 56%). The H NMR spectrum of 5 exhibited a
characteristic broad singlet at δ 6.25 ppm attributable to NH proton and a singlet at δ
1
3
3
.74 ppm (OCH ). Further proof for the structure of 5 arose from the C NMR data
3
which displayed a methoxy signal δ 55.3 ppm and a carbonyl signal at δ 160.5 ppm.
3
1
Also, the P NMR spectrum of 5 showed a phosphorus atom signal at δ 54.6 ppm.
Finally, the IR and mass spectra were in agreement with the suggested structure.

6
O M e
O
O
S
P
N H2
L R
N
H
S H
D io xa n e
O
N H
O
N H
1
C
5
6 %
O
6
5
4
5
a
4 a
3
7
8
N H
2
2 `
3 `
1
1 `
P
9
a
O
1 0 a
N
4 `
9
S
O M e
S
P
S
5
6
`
5
`
S
P
S
M e O
S
P
S
+
L R
=
O M e
=
2
O M e
Scheme 4.
EXPERIMENTAL
Melting points were determined in an open capillary tube on a digital Stuart
SMP-3 apparatus. IR spectra were measured on a FT-IR (Nicolet IS10)
1
spectrophotometer and Perkin-Elmer 293 spectrophotometers using KBr disks. H and
1
3
C NMR spectra were measured on a Gemini-300BB spectrometer (400 and 100
3
1
MHz), using DMSO-d as solvent and TMS (δ) as internal standard. P-NMR spectra
6
were measured on a Bruker (162 MHz) spectrophotometer using DMSO-d as solvent,
6
TMS as an internal standard and 85% H PO as external reference. Mass spectra were
3
4
recorded on a Gas Chromatographic GCMSqp 1000 ex Shimadzu instrument at 70
eV. Elemental microanalyses were performed on a Perkin-Elmer 2400II at the
Chemical War department, Ministry of Defense. Phosphorus decasulfide and
’
Lawesson s reagent used in this work were purchased from Sigma-Aldrich and were
used without further purification. The reactions were performed in air without any an
inert atmosphere. The purity of the synthesized compounds was checked by thin layer
chromatography (TLC) and elemental microanalysis.

7
2
-Imino-2H-chromene-3-carboxamide (1)
A solution of 2-cyanoacetamide (1.68 g, 20 mmol) in absolute ethanol (40 mL)
was stirred with salicylaldehyde (2.44 mL, 20 mmol) in the presence of NEt (0.4 mL)
3
for 30 min. The formed solid was filtered off, washed with EtOH and crystallized
15
from EtOH to give yellow crystals in 85% yield; mp. 188-190 °C (lit. 184-185 °C).

1
IR (vmax, cm ): 3419 (br, OH), 3312, 3289, 3140 (3 NH), 3060 (C-Harom), 1698
+
+
(
C=O), 1636 (C=N), 1601, 1568 (C=C). MS (m/z, I %): 189 [(M+1) , 10%], 188 (M ,
7
0%). Anal. calcd. for C H N O (188.18): C, 63.82%; H, 4.28%; N, 14.89%. Found:
1
0
8
2
2
C, 63.51%; H, 3.99%; N, 14.61%.
-Sulfanyl-2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diazaphosphinin-4-
2
one (2A) and 4-hydroxy-2-sulfanyl-2-sulfido-2H-chromeno[2,3-d][1,3,2]diaza-
phosphinine (2B)
A mixture of 1 (0.94 g, 5 mmol) and P S (2.22 g, 5 mmol) in dry dioxane (30
4
10
mL) was heated under reflux for 7 h. The formed solid was filtered off, washed with
EtOH and crystallized from diluted EtOH to give an orange solid in 95% yield; mp.

1
1
1
6
24-125 °C. IR (vmax, cm ): 3361 (br, OH), 3200 (br, NH), 1710 (C=O), 1633 (C=N),
1
611, 1569 (C=C), 700 (P=S). H NMR: 6.79 (br, 1H, SH exchangeable with D O),
2
.91, 7.23 (two t, 1H, J = 7.6 and 7.2 Hz, 7-H), 6.98, 7.19 (two d, 1H, J = 7.6 and 8.4
Hz, 9-H), 7.40-7.48, 7.68-7.75 (two m, 1H, 8-H), 7.50, 7.95 (two d, 1H, J = 8.4 and
.0 Hz, 6-H), 7.89, 8.05 (two s, 1H, NH and OH exchangeable with D O), 8.35, 8.85
8
2
1
3
(
two s, 1H, 5-H). C NMR: 115.4, 116.6 (C-9), 116.8, 118.9 (C-4a), 119.4, 119.7 (C-
5
1
a), 124.4, 125.5 (C-7), 128.5, 130.3 (C-6), 133.4, 134.6 (C-8), 146.4, 148.3 (C-5),
+
54.5 (C-9a), 158.3 (C-10a), 160.7, 163.0 (C-4). MS (m/z, I %): 282 (M , 5%). Anal.
calcd. for C H N O PS (282.27): C, 42.55%; H, 2.50%; N, 9.92%; S, 22.72%.
1
0
7
2
2
2
Found: C, 42.22%; H, 2.23%; N, 9.58%; S, 22.48%.

8
2
-Oxo-2H-chromene-3-carboxamide (3)
A solution of 2 or 4 (0.2 g) in DMF (10 mL) was boiled for 10 min. The solution was
left to cool. The formed solid was filtered off and dried to give yellow crystals in
2
2
1
6
3
5−80% yield; mp. 278-280 °C (lit. 280-281 °C). IR (v , cm ): 3388, 3149 (NH ),
max 2
055 (C-Harom), 1737 (C=Olactone), 1678 (2 C=Oamide), 1602, 1564 (C=C).
Pyridinium
phinine 2-sulfide (4)
Method A: A solution of 2 (0.2 g) in dry pyridine (10 mL) was warmed at 60 °C for
5 min. The solid formed after cooling was filtered off, washed with diethyl ether and
4-oxo-2,3-dihydro-2-sulfido-4H-chromeno[2,3–d][1,3,2]diazaphos-
1
dried to give a yellow solid in 50% yield; mp. 202-203 °C.
Method B: A solution of P S (2.22 g, 5 mmol) in pyridine (20 mL) was heated under
4
10
reflux for 2 h to form the pyridine complex. A solution of 1 (0.94 g, 5 mmol) in dry
pyridine (10 mL) was added to the above solution and refluxed for 5 h. The formed
solid was filtered off, washed with diethyl ether and crystallized from dioxane to give
1
a yellow solid in 30% yield; mp. 203-205°C. IR, (v max, cm ): 3291 (NH), 3149
(NH), 3066, 3024 (C-Harom), 1699 (C=O), 1610 (C=N), 1599, 1562 (C=C), 679 (P=S).
1
H NMR: 7.41 (t, 1H, J = 7.6 Hz, 7-H), 7.47 (d, 1H, J = 8.4 Hz, 9-H), 7.61 (d, 1H, J =
8
1
.4 Hz, H ), 7.70-7.77 (m, 3H, 8-H, H , H ), 7.88 (d, 1H, J = 8.0 Hz, 6-H), 7.96 (d,
β β' 
H, J = 8.0 Hz, H ), 8.16 (d, 1H, J = 6.6 Hz, H ), 8.89 (s, 1H, 5-H), 9.77 (s, 1H, NH,
α
α'
13
exchangeable with D O), 10.31 (brs, 1H, NH, exchangeable with D O). C NMR:
2
2
1
16.4 (C-9), 116.5 (C-4a), 118.9 (C-5a), 125.2 (C-7), 125.6 (C ), 130.7 (C-6), 133.9
β,β'
(
C ), 134.4 (C-8), 135.9 (C ), 148.3 (C-5), 153.9 (C-9a), 159.3 (C-10a), 193.6 (C-4).
 α,α'
+
MS (m/z, I %): 361 (M , 2%). Anal. calcd. for C H N O PS (361.37): C, 49.85%;
1
5
12
3
2
2
H, 3.35%; N, 11.63%; S, 17.75%. Found: C, 49.51%; H, 3.13%; N, 11.30%; S,
7.48%.
1

9
2
-(4-Methoxyphenyl)-4-oxo-2-sulfido-2,3-dihydro-4H-chromeno[2,3-d][1,3,2]diaza-
phosphinine (5)
LR (1 g, 5 mmol) was added to a solution of 1 (0.94 g, 5 mmol) in dry dioxane
(30 mL). The mixture was heated under reflux for 7 h. The formed solid was filtered
off and washed with hot dioxan to give a yellow solid in 56% yield; mp. 250−252 °C.

1
IR, (v max, cm ): 3367 (br, NH), 3051 (C-Harom), 1720 (C=O), 1673 (C=N), 1611,
1
1
598 (C=C), 1077 (O-C), 651 (P=S). H NMR: 3.74 (s, 3H, OCH ), 6.25 (d, 1H, J
3
NHP
'
'
=
100 Hz, NH exchangeable with D O), 6.77 (d, 2H, J = 8.0 Hz, 3-H, 5-H), 6.85 (d,
2
'
'
1
H, J = 7.5 Hz, 9-H), 7.37 (t, 1H, J = 8.0 Hz, 7-H), 7.47 (d, 2H, J = 8.0 Hz, 2-H, 6-
1
3
H), 7.55 (t, 1H, J = 7.8 Hz, 8-H), 7.74 (d, 1H, J = 8.0 Hz, 6-H), 8.87 (s, 1H, 5-H). C
'
'
NMR: 55.3 (OCH ), 110.6 (C-3,5), 113.1 (C-9), 116.8 (C-4a), 118.0 (C-5a), 125.6
3
'
'
'
(
C-7), 129.1 (C-2,6), 130.7 (C-6), 132.8 (C-1), 135.0 (C-8), 147.4 (C-5), 150.0 (C-
'
31
4
), 154.0 (C-9a), 157.9 (C-10a), 160.5 (C-4). P NMR: 54.6 ppm. MS (m/z, I %): 358
+
+
[
(M+2) , 17%), 356 (M , 56%). Anal. calcd. for C H N O PS (356.33): C, 57.30%;
17 13 2 3
H, 3.68%; N, 7.86%; S, 9.00%. Found: C, 57.02%; H, 3.43%; N, 7.57%; S, 8.69%.
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