Synthesis and biological evaluation of coumarinyl sydnone derivatives

Article abstract of DOI:10.1155/2011/705856

A novel series of compounds containing coumarinyl sydnone derivatives from 4-methyl-7-hydroxy-8-nitro coumarin were synthesized. The formed compounds have been evaluated by physical methods (melting point, thin layer chromatography, elemental analysis) an

Full text of DOI:10.1155/2011/705856

ISSN: 0973-4945; CODEN ECJHAO
E-Journal of Chemistry
2011, 8(1), 113-118
http://www.e-journals.net
Synthesis and Biological Evaluation of
Coumarinyl Sydnone Derivatives
KESHAV C. PATEL* and HIMANSHU D. PATEL
Department of Chemistry
Veer Narmad South Gujarat University, Surat-395 007, Gujarat, India
drkcpatel55@gmail.com
Received 10 May 2010; Accepted 20 July 2010
Abstract: A novel series of compounds containing coumarinyl sydnone
derivatives from 4-methyl-7-hydroxy-8-nitro coumarin were synthesized. The
formed compounds have been evaluated by physical methods (melting point,
1
thin layer chromatography, elemental analysis) and by spectral data (IR, H-
NMR & 13C NMR). The antimicrobial evaluation of the compounds showed
that some of them revealed promising antimicrobial activity.
Keywords: Coumarin, Sydnone, Antimicrobial activity, Synthesis.
Introduction
Sydnone contain a mesoionic aromatic system, which can be depicted with polar resonance
structure1. Sydnone, the potential basic pharmacodynamic nucleus has been reported to
possess a wide variety of biological activities2-4 which include antitumor5, anticancer6, anti-
inflammatory7, antiviral8,9, scavenging activity10, antimalarial11, central nervous system
stimulant12, HIV Protease inhibitor13.
Coumarin and its derivatives have proved a wide spectrum of pharmacological activities.
Further coumarin derivatives which on attachment with heterocyclic ring, such as thiazole,
triazole14 sydnone15 exhibit promising biological activities. We report herein the synthesis of a
series of novel coumarinyl sydnone derivatives. Its derivatives have taken the coumarin
framework to a respectable position in the drugs designing. However, very limited work has
been focused on the development of coumarinyl sydnone. As on method of preparation, we
used a cyclodehydration of α-amino acids N-nitroso derivatives, the method which remains the
sole useful synthetic rout for the preparation of sydnone since Earl and Mackey’s synthesis of
sydnone16 Review17 for the synthesis of 8-amino coumarin by Pechmann condensation of
.
resorcinol with ethylacetoacetate in presence of condensing agent i.e. H2SO4 is well known.
Experimental
The melting points were determined in open capillaries and are uncorrected. The purity of
the compounds was controlled by TLC. The spectral data of all the newly synthesized

114
KESHAV C. PATEL et al.
compounds, given below, were in full agreement with the proposed structures. Elemental analyses
were recorded on Carlo-erba and Perkin Elmer for CHN elements. IR (KBr) spectra were recorded
on RZX (Perkin-Elmer) FT-IR model-377 spectrophotometer. 1H NMR spectra were recorded on
FT-NMR Cryo-magnet Spectrometer 400 MHz (Bruker) in DMSO-d6 as solvent using TMS as
internal reference and chemical shifts (d) are expressed in ppm. 13C NMR spectra were recorded
on Varian Mercury VX 300 NMR using DMSO-d6 as solvent and TMS as an internal standard.
Mass spectra were recorded on LC-MS Q-ToF micro analyzer (Shimadzu). The synthesis of 8-
amino-7-(alkoxyl / aryloxyl)-4-methyl-coumarinyl]sydnone is shown in Scheme 1.
N+ O-
O
O
O
O
O
OH
Nitration
OH
Conc. HNO3 + Conc. H2SO4
CH3
1
CH3
2
O-
N+
NH2
O
O
O
O
O
OH
OH
Na metal
Reduction
Na2S
HBr / RBr
CH3
CH3
3a-i
4a-i
H2C
HN
COOC2H5
COONa
H2C
NH
Cl.CH2COOC2H5
NaOAc
O
O
O
O
OH
OH
4a-i
Hydrolysis
EtOH / NaOH
MeOH
Reflux 7-8 h
CH3
CH3
5a-i
OH
N
6a-i
O
O
O
O
N
N
H2C
HC
O
N
Cyclisation
Nitrosation
NaNO2 / HCl
O
O
Ac2O
O
OH
OH
Reflux 5-7 h
0 - 5 °C
CH3
CH3
7a-i
8a-i
R: - H, -CH3, -C2H5, -C3H7, -C4H9,.......etc.
Scheme 1. Synthesis of synthesis of 8-amino-7-(alkoxyl / aryloxyl)-4-methyl-coumarinyl]
sydnone. (8a:3-[8-{7-(hydroxy)-4-methyl}coumarinyl]sydnone, 8b:3-[8-{7-(methoxy) -4-methyl}
coumarinyl]sydnone, 8f:3-[8-{7-(benzyloxy)-4-methyl} coumarinyl] sydnone)
Synthesis of 4-methyl-7-hydroxy-8-nitro coumarin (2)
A solution of conc. nitric acid (4.90 mL, 0.0775 mol) in concentrated sulphuric acid
(5.1 mL) was added to a stirred solution of 4-methyl-7-hydroxy coumarin (13.64 g, 0.0775 mol)
o
in conc. sulphuric acid (30 mL) at such a rate as to keep the temperature below 5 C. After
o
warming to 20 C, the reaction mixture was poured into a stirred mixture of ice cold water.
The yellow solid that separated was filtered and thoroughly washed with water. The product
was recrystalized first from glacial acetic acid and then methyl ethyl ketone to give pure (2).
Yield 93%, mp. 256 oC.

Synthesis and Biological Evaluation of Coumarinyl Sydnone Derivatives
115
General method for the preparation of alkyl / aryl halide (3a-g)
A 250 mL two necked round bottom flask was equipped with a dropping funnel and an efficient
double surface condenser, the upper end of which was protected with a calcium chloride gourd
drying tube. In this flask, 3.32 g (0.14 mol) of lustrous metallic sodium, cut into pieces, was
added into 40 mL of absolute ethanol. When all the sodium had dissolved, the solution was
cooled and 0.14 mole of alkyl/aryl bromide and 0.1 mol (2) were added to it and stirred well and
refluxed on water bath for 4-5 h in preparation of alkoxy acetanilide and 8-10 h in preparation
aryl alkoxy derivatives. Then 100 mL of water was poured through the condenser. The flask was
cooled and solid was washed and recrystalized from ethanol. The yields were 80-90%.
Preparation of 3i
50 ML three necked round bottom flask fitted with a reflux condenser, a dropping funnel and a
stirring unit was used, 0.025 mol of 4-methyl-7-hydroxy-8-nitro coumarin, 0.85 g (0.01 mol) of
tetra butyl ammonium hydrogen sulphate, 10 mL of dichloromethane, 50% w/w aqueous sodium
hydroxide (2.6 g sodium hydroxide in 2.6 g of water) added into it and vigorously stirred for half
an hour. The flask was cooled in ice cold water bath and 3.8 g (0.03 mol) of dimethyl sulphate
was added through a funnel for a period of 1 h. The mixture was stirred vigorously at room
temperature until TLC analysis revels the reaction is completed (usually about 3 h). 1 mL of
conc. ammonia was added and stirred for further half an hour at room temperature to decompose
excess dimethyl sulphate. The reaction mixture was poured into water and then added with
20 mL of dichloromethane, the organic layer was separated and washed with water until the
washing are neutral. The product was dried over magnesium sulphate and evaporated the solvent
on a rotatory evaporator. The product is obtained; yield 78%, (3.40 g), m.p. 260 oC.
General method for the synthesis 8-amino-7-(alkoxyl / aryloxyl)-4-methyl-coumarin (4a-i)
A solution of sodium hydrosulphite 7 g, (0.04 mol) in water 30 mL was added rapidly to pure
derivative of 7-(substituted-OH)-4-methyl-8-nitro coumarin 2.37 g, (0.0107 mol) in 36%
20 mL of aqueous ammonia. The mixture was warmed spontaneously with stirring, yellow
precipitates or solid that separated was filtered and recrystalized from ethanol.
Synthesis of various alkoxyl / aryloxyl glycines ethyl esters (5a-i)
Derivatives of hydroxyl-8-amino coumarin (0.10 mol), ethylchloroacetate (0.10 mol) and
sodium acetate crystals (0.10 mol) in ethanol were heated for 5 h. In the case of aryl alkoxy
amino derivatives the equimolar mixture was heated with little excess of ethanol. The
reaction mixture was poured into water. The separated oily layer was extracted with ether,
washed well with water and dried over anhydrous sodium sulphate.
Synthesis of various alkoxyl / aryloxyl coumarinyl glycines (6a-i)
The crude esters were hydrolyzed by refluxing with 5% excess of sodium hydroxide in ethanol
for 30 min. The crude sodium salts of glycine were filtered and directly used for nitrosation.
Synthesis of various alkoxyl / aryloxyl N-coumarinyl-N-nitrosoglycine (7a-i)
Sodium salt of glycine (0.10 mol), sodium nitrate (5 g) in 20 mL of water was taken in
o
250 mL beaker and cooled to 0 C, the nitroso compound was filtered off and washed well
with cold water and dried over sodium hydroxide pellets. Yield 60-65%.
General procedure for the synthesis of (8a-i)
Compounds 7(a-i) (0.010 mol) and acetic anhydride 6.7 g (0.050 mol) were heated for 5-7 h. The
mixture was poured into alkaline ice water. The crude product was filtered and washed well with
water and dried. The product was recrystallized from benzene-petroleum ether. Yield was 55-60%.

116
KESHAV C. PATEL et al.
3-[8-{7-(Hydroxy)-4-methyl}coumarinyl]sydnone (8a)
Yield 56%; m.p. 107 ˚C; Anal. Calcd. for C12H10O5N2: C, 54.97; H, 3.84; N, 10.68. Found: C,
54.99; H, 3.88; N, 10.70. IR (KBr, cm−1): 3317, 3150, 1730, 1025. 1H NMR (400 MHz, DMSO-d6,
ppm): 2.32 (s, 3H, -CH3), 5.23 (s, 1H, OH), 6.38-7.10 (s, 3H, Aromatic -CH), 8.20 (s, 1H, -NH).
13C-NMR (75 MHz, DMSO-d6, δ, ppm): 161.09, 152.07, 140.91, 135.71, 122.21, 116.61, 114.11,
113.09, 112.49, 109.10, 73.60, 19.35. m/z: 264.17 (100.0%), 265.05 (13.3%), 266.18 (1.9%)
3-[8-{7-(Methoxy)-4-methyl} coumarinyl]sydnone (8b)
o
Yield 52%; m.p. 132 C; Anal. Calcd. for C13H12O5N2: C, 56.52; H, 4.37; N, 10.14. Found:
C, 56.55; H, 4.39; N, 10.16. IR (KBr, cm−1): 3175, 2830, 1745, 1010. 1H-NMR (400 MHz,
DMSO-d6, ppm): 2.32 (s, 3H, -CH3), 3.81 (s, 3H, -OCH3), 4.08 (s, 1H, -CH), 6.25-7.20, (s,
3H, Aromatic -CH), 8.20 (s, 1H, -NH). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 161.90,
152.67, 144.83, 135.34, 121.21, 116.30, 113.74, 112.11, 111.32, 109.10, 73.60, 55.7, 19.35.
m/z: 278.07 (100.0%), 279.17 (15.0%), 280.17 (1.1%)
3-[8-{7-(Ethoxy)-4-methyl} coumarinyl]sydnone (8c)
Yield 54%; m.p. 129 oC; Anal. Calcd. for C14H14O5N2:C, 57.92; H, 4.86; N, 9.64. Found: C, 57.90;
H, 4.84; N, 9.67. IR (KBr, cm−1): 3140, 2925, 1720, 1020. 1H-NMR (400 MHz, DMSO-d6, ppm):
1.80 (t, 3H), 2.20 (s, 3H), 6.75 (s, 1H), 6.08 (s, 1H), 7.20 (s, 1H), 8.25 (s, C5H). 13C-NMR (75 MHz,
DMSO-d6, δ, ppm): 160.91, 152.71, 141.32, 134.82, 120.80, 115.82, 113.30, 112.24, 111.71,
109.12, 73.81, 64.54, 19.35, 14.92. m/z: 292.21 (100.0%), 293.05 (15.5%), 294.10 (2.2%).
3-[8-{7-(N-Propoxy)-4-methyl} coumarinyl]sydnone(8d)
Yield 54%; m.p.140 oC; Anal. Calcd. for C15H16O5N2: C, 59.20; H, 5.29; N, 9.20. Found: C,
1
59.22; H, 5.31; N, 9.23. IR (KBr, cm−1): 3210, 2890, 1715, 1015. H-NMR (400 MHz,
DMSO-d6, ppm): 1.1 (t, 3H), 1.7-2.0 (m, 2H), 2.04 (s, 3H), 4.0 (t, 2H), 6.79 (s, 1H), 6.9 (s,
1H, Sydnone), 7.12 (s, C6H), 8.9 (s, C5H). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 160.90,
152.67, 141.83, 134.92, 121.20, 115.72, 113.40, 112.17, 111.41, 109.22, 76.40, 73.78,
22.64, 19.35, 10.29. m/z: 306.21 (100.0%), 307.09 (17.0%), 308.17 (2.3%).
3-[8-{7-(N-Butoxy)-4-methyl} coumarinyl]sydnone (8e)
Yield 56%; m.p. 150 oC; Anal. Calcd. for C16H18O5N2: C, 60.37; H, 5.69; N, 8.81. Found: C,
1
60.40; H, 5.67; N, 8.83. IR (KBr, cm−1): 3170, 2900, 1740, 1035. H-NMR (400 MHz,
DMSO-d6, ppm): 1.1 (t, 3H), 1.8-2.0 (m, 4H), 2.03 (s, 3H), 4.02 (t, 2H), 6.75 (s, C3H), 6.95
(s, 1H), 7.02 (s, C6H), 8.18 (s, C5H). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 160.91,
152.71, 141.32, 134.82, 120.80, 115.82, 113.30, 112.24, 111.71, 109.12, 73.81, 67.95,
31.76, 19.35, 19.01, 14.92. m/z: 320.17 (100.0%), 321.21 (17.7%), 322.07 (2.6%)
3-[8-{7-(Benzyloxy)-4-methyl} coumarinyl]sydnone (8f)
Yield 50%; m.p. 142 oC; Anal. Calcd. for C19H16O5N2: C, 64.76; H, 4.57; N, 7.95. Found: C,
64.77; H, 4.55; N, 7.98. IR (KBr, cm−1): 3150, 2920, 1735, 1040 cm-1. 1H-NMR (400 MHz,
DMSO-d6, ppm): 2.42 (s, 3H, -CH3), 4.08 (s, 1H, -CH), 6.25-7.40, (s, 8H, Aromatic -CH),
8.20 (s, 1H, -NH). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 160.91, 157.04, 153.07, 136.7,
134.07, 128.42, 123.57, 121.03, 119.01, 114.95, 114.62, 112.54, 109.10, 74.10, 19.26. m/z:
340.09 (100.0%), 341.19 (19.8%), 342.10 (3.0%)
3-[8-{7-((P-Chloro benzyl)oxy)-4-methyl} coumarinyl]sydnone (8g)
Yield 57%; m.p. 140 oC; Anal. Calcd. for C19H15O5N2Cl: C, 59.00; H, 3.89; N, 7.25. Found:
1
C, 59.03; H, 3.92; N, 7.22. IR (KBr, cm−1): 3145, 2935, 1710, 1020, 752. H-NMR (400
MHz, DMSO-d6, ppm): 2.41 (s, 3H, -CH3), 4.14 (s, 1H, -CH), 6.25-7.65, (s, 7H, Aromatic –

Synthesis and Biological Evaluation of Coumarinyl Sydnone Derivatives
117
CH), 8.22 (s, 1H, -NH). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 160.89, 155.01, 152.91,
136.40, 134.12, 129.45, 127.20, 123.87, 118.88, 114.85, 114.53, 112.49, 109.08, 73.65, 19.41.
m/z: 374.16 (100.0%), 376.05 (32.0%), 375.17 (19.8%), 377.12 (6.6%), 376.09 (3.0%)
3-[8-{7-((P-Methyl benzyl)oxy)-4-methyl} coumarinyl]sydnone (8h)
Yield 55%; m.p. 146 oC; Anal. Calcd. for C20H18O5N2: C, 65.56; H, 4.95; N, 7.64. Found: C,
1
65.57; H, 4.97; N, 7.61. IR (KBr, cm−1): 3150, 2880, 1725, 1015. H-NMR (400 MHz,
DMSO-d6, ppm): 2.34 (s, 6H, -CH3), 4.08 (s, 1H, -CH), 6.25-7.15, (s, 7H, Aromatic -CH),
8.21 (s, 1H, -NH). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 160.91, 154.01, 152.81, 136.54,
134.02, 131.45, 128.15, 123.87, 117.08, 114.97, 114.64, 112.59, 109.48, 73.65, 21.51,
19.35. m/z: 354.21 (100.0%), 355.13 (21.3%), 356.14 (3.1%)
3-[8-{7-((P-Fluoro benzyl)oxy)-4-methyl} coumarinyl]sydnone (8i)
o
Yield 58%; m.p. 139 C; Anal. Calcd. for C19H15O5N2F: C, 61.62; H, 4.08; N, 7.56. Found:
1
C, 61.60; H, 4.10; N, 7.59. IR (KBr, cm−1): 3150, 2910, 1715, 1075, 1030. H-NMR
(DMSO-d6, ppm): 2.44 (s, 3H, -CH3), 4.12 (s, 1H, -CH), 6.25-7.35, (s, 7H, Aromatic -CH),
8.14 (s, 1H, -NH). 13C-NMR (75 MHz, DMSO-d6, δ, ppm): 160.78, 156.23, 152.71, 136.64,
134.01, 123.77, 120.09, 115.24, 114.54, 114.92, 112.32, 109.21, 73.75, 19.35. m/z: 358.11
(100.0%), 359.15 (19.8%), 360.08 (3.0%)
Results and Discussion
Antimicrobial activity
The synthesized compounds 8(a-i) were tested for their antibacterial activity in vitro in
comparison with ampicillin and penicillin as a reference drug using the standard agar disc
diffusion method19 against bacterial species: Escherichia coli (ATCC 25922), Pseudomonas
aeruginosa (ATCC 10145), Staphylococcus aureus (ATCC 25923) and Bacillus subtils
(ATCC 6633). All the synthesized compounds were weighed and dissolved in DMSO to
prepare exact stock solution of 100 µg/mL.
The antimicrobial effects of the substances were tested quantitatively in respective broth
media by using double dilution and the zone of inhibition values were determined. The
antibacterial were performed in Muller-Hinton broth (MH) (Difco, Detroit, MI) at pH 7.3
and Buffered Yeast Nitrogen Base (Difco, Detroit, MI) at pH 7.0, respectively. Ampicillin
(Amp) and penicillin (Pen) were used as standard antibacterial. DMSO with dilution of 1:10
was used as solvent control. The results are shown in Table 1.
Table 1. Antimicrobial activity of the tested compounds (8a-i)
Bacillus
subtills
Escherichia
coli
Staphylococcus
aureus
Pseudomonas
aeruginosa
Compd.
No.
IZ
19
16
19
20
24
25
21
26
20
29
25
MIC
250
250
125
500
125
250
500
125
500
125
125
IZ
20
20
21
20
22
20
23
21
20
25
24
MIC
125
125
250
500
250
125
500
250
125
125
250
IZ
MIC
125
250
500
500
125
250
125
250
500
250
125
IZ
15
20
21
20
23
24
20
21
20
23
24
MIC
500
125
250
250
500
125
500
500
125
125
125
8a
8b
8c
8d
8e
8f
8g
8h
8i
Amp.
Pen.
23
25
21
26
20
21
20
19
19
28
27
IZ – Zone of Inhibition in mm., MIC- Minimal Inhibitory Concentration in µg/mL

118
KESHAV C. PATEL et al.
We report the synthesis of some new 8-heterocyclic coumarin derivatives. Novel
compounds were synthesized by using resorcinol as a starting material and prepared 1,
which on nitration gives compound 2, then it was reacted with Na metal & various alkyl,
aryl halide or acetyl derivatives to give compound 3 which on nitration, reduction,
nitrosation, cyclization etc. we got coumarinyl sydnone18. The synthesis of 8-amino-7-
(alkoxyl / aryloxyl)-4-methyl-coumarin (4a-i) (Scheme 1) was investigated, which on
further react with EAA and NaOAc followed by hydrolysis, nitrosation and cyclisation gives
desired sydnone derivatives (8a-i).
Conclusion
We have synthesized new coumarinyl based sydnone derivatives by conventional method
and screened for their antimicrobial activity. The newly synthesized sydnone drugs were
successfully characterized by IR, NMR and elemental analysis. From the antimicrobial
activity data compound 8b, 8g and 8h showed broad spectrum activity against selected
bacteria with respect to standard drug ampicillin and penicilin, other compound showed
moderate to weak activity.
Acknowledgment
The authors thank to Professor and Head, Department of Chemistry, Veer Narmad South
Gujarat University, Surat for providing laboratory facilities. The authors express their thanks
and gratefully acknowledges the financial support (Fellowship) rendered by UGC-SAP, New
Delhi. The authors also thank to SAIF, Chandigarh for IR and NMR spectral analysis. Author
sincerely thankful to Mr. Ramprasad Kahar for his kind support during the synthesis work.
References
1.
2.
Mullur S G and Badami B V, Farmaco, 2000, 55(1), 65-67.
McNaught A D in, Adv Heterocyclic Chem, Katritzky A R and Boulton A J (Eds.),
Advances Heterocyclic Chemistry, Academic Press New York, 1976, 175-319
Moustafa M A, Nasr M N, Gineinah M M and Bayoumi W A, Arch Der Pharmazie,
2004, 337, 164-170.
3.
4.
5.
6.
Kavali R Jyoti and Badami B V, Farmaco, 2000, 55(5), 406-409.
Dunkley C S and Thoman C J, Bioorg Med Chem Lett., 2003, 13(17), 2899-2901.
Thamotharan S, Parthasarathi V, Mallur S, Kamble R, Badami B and Linden A, Acta
Cryst., 2004, E60, 701-702.
7.
8.
9.
Kalluraya B, Rahiman A M, Polish J Chem., 1997, 71, 1049-1052.
Pandey V K and Tandon M, Indian J Heterocycl Chem,, 2006, 15, 399-400.
Bourinbaiar A S, Tan X and Nagorny R, Acta Virol., 1993, 37, 241-250.
10. Shih M H and Ke F Y, Bioorg Med Chem., 2004, 12, 4633-4633.
11. Friedman M D, Stotter P L, Porter T H and Folkers K, J Med Chem., 1973, 16(11),
1314-1316.
12. Stein, P. Reinhardt, US Patent, 1981, 4289885.
13. Tummino P J, Ferguson D and Hupe D, Biochem Biophy Res Comm., 1994, 201(1), 290-294.
14. Shinge P, Latthe P and Badami B, Synth Commun., 2005, 35(16), 2169-2176.
15. Earl J C and Mackney A W, J Chem Soc., 1935, 899.
16. Sethna S and Phadke R, Org React., 1953, 7, 1-58.
17. Ohta M and. Kato H, Non-Benzenoid Aromatics, 1969, 1, 117-248.
18. Eade R A and Earl J C, J Chem Soc., 1946, 591-593.
19. Arthington-Skaggs B A, Motley M, Warnock D W and Morrison C J, J Clin
Microbiol., 2000, 38, 2254-2260.

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