224
B. S. Kumar, M. V. N. Reddy, G. C. S. Reddy, N. B. Reddy, and C. S. Reddy
Vol 48
Table 3
Minimum inhibitory concentration of compounds 3a–j (lg/mL).
Bacteria
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
Escherichia coli
Staphylococcus aureus
600
550
380
400
380
310
540
300
580
410
630
500
390
300
300
620
550
410
400
340
C-500), 132.61 (C-400), 63.5 (d, 2JPOC
¼
7.3 Hz,
C-70a), 134.02 (C-100), 128.09 (C-200 and C-600), 127.71 (C-300 and
3
2
PAOCH2ACH3), 15.3 (d, JPOCC ¼ 6.1 Hz, PAOCH2ACH3);
31P-NMR data: d 31.49 (P¼¼O, phosphonates), 1.91 (P¼¼O, dia-
zaphosphole); Anal. Calcd. for: C34H41N2O17P3: C, 59.82; H,
6.05; N, 4.10. Found C, 59.78; H, 6.00; N, 4.05.
C-500), 131.90 (C-400), 55.13 (OCH3) 62.5 (d, JPOC ¼ 7.5 Hz,
3
PAOCH2ACH3), 16.3 (d, JPOCC ¼ 6.9 Hz, PAOCH2ACH3);
31P-NMR data: d 25.32 (P¼¼O, phosphonate), 1.02 (P¼¼O, diaza-
phosphole); Anal. Calcd. for: C38H49N2O11P3: C, 56.86; H, 6.15;
N, 3.49. Found C, 56.80; H, 6.10; N, 3.44.
[{(3-Diethoxy-phosphoryl)-(4-chloro-phenyl-methyl)-2-oxo-2-
phenyl-2,3-dihydro-2ꢀ5-benzo[1,3,2]diazaphosphol-1-yl}-(4-
chloro-phenyl)-methyl]-phosphonic acid diethyl ester (3g). Yield
68%, mp 195–197ꢀC. IR (KBr) cmꢁ1: 1261 (P¼¼O, phospho-
nate), 1201 (P¼¼O, diazaphosphole), 757 (PAC); 1H-NMR
(DMSO-d6): 66.6–8.4 (m, 17H, ArH), 5.58 (2H, d, J ¼ 11.5
Hz, PCH), 3.61–4.04 (m, 8H, POCH2CH3), 1.25 (6H, t, J ¼
8.0 Hz, POCH2CH3), 1.09 (6H, t, J ¼ 7.9 Hz, POCH2CH3);
31P-NMR data: d 29.82 (P¼¼O, phosphonates), 2.47 (P¼¼O, dia-
zaphosphole); Anal. Calcd. for: C34H39N2O7P3Cl2: C, 54.34;
H, 5.23; N, 3.73. Found C, 54.30; H, 5.20; N, 3.69.
[{(3-Diethoxy-phosphoryl)-(3-nitro-phenyl-methyl)-2-oxo-2-
phenyl-2,3-dihydro-2ꢀ5-benzo[1,3,2]diazaphosphol-1-yl}-(3-nitro-
phenyl)-methyl]-phosphonic acid diethyl ester (3h). Yield 69%,
mp 227–229ꢀC. IR (KBr) cmꢁ1: 1271 (P¼¼O, phosphonate),
1211 (P¼¼O, diazaphosphole), 762 (PAC); 1H-NMR (DMSO-
d6): 6.1–8.3 (m, 17H, ArH), 5.24 (2H, d, J ¼ 10.8 Hz, PCH),
3.73–4.17 (m, 8H, POCH2CH3), 1.22 (6H, t, J ¼ 8.5 Hz,
POCH2CH3), 1.12 (6H, t, J ¼ 7.8 Hz, POCH2CH3); 31P-NMR
data: d 22.13 (P¼¼O, phosphonate), 3.12 (P¼¼O, diazaphosp-
hole); Anal. Calcd. for: C34H39N4O11P3: C, 53.85; H, 5.09; N,
7.25. Found C, 52.80; H, 5.03; N, 7.20.
Antimicrobial activity. Antimicrobial activity of 3a–j was
tested against the growth of Staphylococcus aureus (ATCC
25923) (Gram þve) and Escherichia coli (ATCC 25922)
(Gram ꢁve) by disc diffusion method at various concentrations
(100, 50, and 25 ppm; Table 1) [16]. All the compounds
showed moderate activity against both the bacteria. The high-
light is that the five compounds, 3b, 3c, 3g, 3h, and 3j were
more effective than even the standard penicillin.
They were also screened for antifungal activity against As-
pergillus niger (ATCC 16404) and Helminthosporium oryzae
(ATCC 11000) species along with the standard fungicide Gris-
eofulvin (Table 2) by the disc diffusion method at three differ-
ent concentrations (100, 50, and 25 ppm). It is gratifying to
observe that majority of the compounds (3a–j) exhibited
higher antifungal activity when compared with that of Griseo-
fulvin. Significant result is that 3b, 3c, 3g, 3h, and 3j exhibited
higher activity than the standard Griseofulvin against both the
fungi. Thus new group of compounds with very high antimi-
crobial/fungicidal activity than the presently used commercial
bactericides/fungicides have been discovered.
Determination of minimum inhibitory concentration. Mini-
mum inhibitory concentration was determined for the com-
pounds 3a–j (Table 3) that showed total growth inhibition
using the protocol described below. The compound concentra-
tion of 50–700 lg/mL in steps of 25 lg/mL was evaluated.
Specifically 0.1 mL of standardized inoculum (1–2 ꢂ 107
CFU/mL) was added to each test tube. Two controls (DMSO
with bacteria and antibiotics with bacteria) were maintained
for each test sample. The tubes were incubated aerobically at
37ꢀC for 18–24 h [17].
[{(3-Diethoxy-phosphoryl)-(3-chloro-phenyl-methyl)-2-oxo-2-
phenyl-2,3-dihydro-2ꢀ5-benzo[1,3,2]diazaphosphol-1-yl}-(3-
chloro-phenyl)-methyl]-phosphonic acid diethyl ester
(3i). Yield 65%, mp 220–222ꢀC. IR (KBr) cmꢁ1: 1267 (P¼¼O,
phosphonate), 1197 (P¼¼O, diazaphosphole), 759 (PAC); 1H-
NMR (DMSO-d6): 6.8–8.5 (m, 17H, ArH), 5.31 (2H, d, J ¼
11.4 Hz, PCH), 3.72–4.11 (m, 8H, POCH2CH3), 1.28 (6H, t,
J
¼
8.1 Hz, POCH2CH3), 1.11 (6H, t,
J
¼
7.7 Hz,
POCH2CH3); 31P-NMR data: d 24.12 (P¼¼O, phosphonates),
2.11
(P¼¼O,
diazaphosphole);
Anal.
Calcd.
for:
Acknowledgments. The authors thank CSIR, Human Resources
Development Group, Government of India, New Delhi, for pro-
viding financial assistance (01/2347/09/EMR-II).
C34H39N2O7P3Cl2. Found C, 54.34; H, 5.23; N, 3.73 C, 54.28;
H, 5.19; N, 3.70.
[{(3-Diethoxy-phosphoryl)-(3,4-dimethoxy-phenyl-methyl)-2-
oxo-2-phenyl-2,3-dihydro-2ꢀ5-benzo[1,3,2]diazaphosphol-1-yl}-
(3,4-dimethoxy-phenyl)-methyl]-phosphonic acid diethyl ester
(3j). Yield 70%, mp 215–217ꢀC. IR (KBr) cmꢁ1: 1269 (P¼¼O,
phosphonate), 1203 (P¼¼O, diazaphosphole), 749 (PAC); 1H-
NMR (DMSO-d6): 6.2–8.2 (m, 29H, ArH), 5.48 (2H, d, J ¼
11.8 Hz, PCH), 3.69–4.08 (m, 8H, POCH2CH3), 1.26 (6H, t,
REFERENCES AND NOTES
[1] Weil, E. D. In Handbook of Organophosphorus Chemistry;
Engel, R., Ed.; Marcel Dekker: New York, 1992; p 683.
[2] Levchik, S.; Weil, E. D. Polym Int 2005, 54, 11.
[3] Du, X. H.; Wang, Y. Z.; Chen, X. T.; Tang, X. D. Polym
Degrad Stab 2005, 88, 52.
J
¼
8.4 Hz, POCH2CH3) 1.14 (6H, t,
J
¼
8.1 Hz,
POCH2CH3), 3.73 (s, 12H,(OCH3); 13C-NMR data: 126.51 (C-
[4] Kiran, Y. B.; Reddy, C. D.; Gunasekar, D.; Raju, C. N.;
Barbosa, L. C. A.; Marney, D. C. O.; Russell, L. J. J. Fire Sci 2007,
25, 193.
ˆ
3 and C-7a), 113.92 (C-4 and C-7), 116.13 (C-5 and C-6),
51.13 (C-10 and C-10a, d, J ¼ 133 Hz), 134.72 (C-20 and C-
20a), 113.22 (C-30 and C-30a), 146.20 (C-40 and C-40a), 144.12
(C-50 and C-50a), 114.96 (C-60 and C-60a), 118.02 (C-70 and
[5] Green, J. In Fire Retardancy of Polymeric Materials; Grand,
A., Wilkie, C.A., Eds.; Marcel Dekker: New York, 2000; p 147.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet