Advanced
Synthesis and Biological Evaluation of 2-Amino-4H-pyran-3,4,5-tricarboxylate Salt Derivatives
Synthesis and Biological Evaluation of 2-Amino-4H-pyran-3,4,5-tricarboxylate Salt Derivatives
Journal of the Korean Chemical Society. 2013. Aug, 57(4): 455-460
Copyright © 2013, Korea Chemical Society
  • Received : March 13, 2013
  • Accepted : June 02, 2013
  • Published : August 20, 2013
Download
PDF
e-PUB
PubReader
PPT
Export by style
Article
Author
Metrics
Cited by
TagCloud
About the Authors
Ali Akbari
Zabihollah Azami-Sardooei
Department of Corp Protection, Faculty of Agriculture, University of Jiroft, Jiroft, P.O.Box 8767161167, Iran
Asghar Hosseini-Nia
Department of Plant Protection National Research Station of Ornamental Plants, Mahallat, P.O.Box 37815-137, Iran

Abstract
A novel and simple method for the synthesis of 2-amino-4 H -pyran-3,4,5-tricarboxylate derivative and the evaluation of their antibacterial activity against Pseudomonas syringae , Xanthomonas citi and Pectobacterium carotovorum are reported. The structure of the isolated compounds has been determined by means of 1 H/ 13 C NMR and FT-IR Spectroscopy. The reaction of alkyl isocyanides with acetylenic esters in the presence of dimethyl acetone-1,3-dicarboxylate in the present of BF 3 .SiO 2 at ambient temperature. Some of the compound showed significant inhibition to growth of bacteria.
Keywords
INTRODUCTION
Homogeneous acidic catalysts such as H 2 SO 4 , HCl and BF 3 are commonly used for organic synthesis. However, the above-mentioned catalysts have several disadvantages because they are corrosive, toxic or volatile, and generate large amounts of waste. Silica supported boron trifluoride, BF 3 .SiO 2 , which is easy to prepare and shows unusually high Brønsted acidity which can be controlled by activation temperature, and exhibits considerable catalytic activity 1 enables better accessibility of the reactants to the active sites. BF 3 .SiO 2 is a solid super acid and has surface species such as Al-OBF 2 and Si-OBF 2 , and the ion pairs,
PPT Slide
Lager Image
or
PPT Slide
Lager Image
The BF 3 .SiO 2 is used in several organic transformations, such as in Claisen-Schmidt condensations, 3 in synthesis of 14-aryl or alkyl-14 H -dibenzo[ a,j ]xanthenes, 4 1,2,4,5-tetrasubstituted imidazoles, 5 in the polymerization of styrene, 6 the preparation of polyfunctionalized piperidin-4-ones, 7 α-amino phosphonates, 8 quinoxalines, 9 and 3,4-dihydropyrimidin-2(1 H )-ones. 10
4 H -pyranes have recently attracted much attention as an important class of heterocyclic having useful biological and pharmacological properties, such as cytotoxic (anticancer), 1113 neuroprotective, 14 HIV-inhibitory, 15 antimicrobial, 16, 17 antifungal, 18 and antioxidant activity. 19 Recently, one methods has been reported for the synthesis of pyran derivatives via a three-component condensation of alkylisocyanides with acetylenic esters and 1,3-diketones to synthesis of 2-amino-4 H -pyran-3,4,5-tricarboxylate derivatives. 20 We reported the synthesis of fused 2-amino-4 H -pyrane derivatives from the reaction of alkylisocyanides with acetylenic esters and 1,3-diketones, in the presence of BF 3 .SiO 2 in H 2 O at room temperature. synthetic methodology for the synthesis of 4 H -pyran as a part of green chemistry approach. H 2 O is a naturally occurring, cheap, and non-toxic ecofriendly solvent. And biological evaluation antibacterial activity against Pseudomonas syringae, Xanthomonas citi and Pectobacterium carotovorum with improved in vitro therapeutic index. These heterocycles then screened for their antibacterial activity against X. campestris pvs, P. syringae and P. carotovorum using Tetracyclin as standard antibiotic. Interestingly some of the compounds revealed better activity.
Pectobacterium carotovorum is a bacterium of the family Enterobacteriaceae; it formerly was a member of the genus Erwinia. The species is a plant pathogen with a diverse host range, including potato, African violet, and other agriculturally and scientifically important plant species. It causes soft rot and blackleg of potato and vegetables, as well as slime flux on many different tree species. 21, 22
Xanthomonas can infect a wide variety of species including pepper, rice, citrus, cotton, tomato, broccoli, cabbage, and soybeans. Some types of Xanthomonas cause localized leaf spot or leaf streak while others spread systemically and cause black rot or leaf blight disease. 23, 24
Pseudomonas syringae is responsible for causing diseases on over 180 plant species including fruit trees, vegetable crops and flowers. Pathovars of main economic importance in Europe are the pvs syringae, morsprunorum, avii and persicae, causing bacterial canker on sweet and sour cherry, plum, peach and apricot as well as in wild cherry. 25, 26
Acetylenic esters, alkyl isocyanides, dimethyl acetone-1,3-dicarboxylate and other chemicals were purchased from Fluka and Merck companies. Products were characterized by IR, 1 H-NMR and by comparison of their physical properties with those reported in the literature. IR spectra were run on a Bruker, Eqinox 55 spectrometer. 1 H-NMR, and 13 C-NMR spectra were obtained using a Bruker Avans 400 MHz spectrometer (DRX). Melting points were determined by a Buchi melting point B-540 B. V. CHI apparatus. The elemental analyser was done by Costech ECS 4010 CHNS-O analyser.
EXPERIMENTAL
- Preparation of BF3.SiO2
0.37 g of BF 3 (0.7 ml of BF 3 .Et 2 O) was added drop wise to a mixture of 0.63 g of silicagel and 5 ml of chloroform. The mixture was stirred for 1 h at room temperature. The resulted suspension was filtered. The obtained solid was washed with chloroform and dried at room temperature for 6 h.
- General Procedure for the Synthesis of 2-Amino-4H-pyran-3,4,5-tricarboxylate Derivative
A mixture of dimethyl acetone-1,3-dicarboxylate (10 mmol, 1.82 ml) and dimethyl or diethyl acetylene dicarboxylate (10 mmol) and BF 3 .SiO 2 (0.32 g, 25 mol %) in 50 ml H 2 O, was added, drop wise at 0 ℃ over 10 min iso-cyanide derivatives (10 mmol). The reaction mixture was then allowed to warm up to room temperature and stand for 6 h. After completion of the reaction, the mixture was extracted once with 50 ml toluene, made strongly alkaline with 25% aq. NaOH and then extracted with 2×50 ml toluene. The combined alkaline extracts was dried over MgSO 4 and the solvent removed by distillation in a rotovap. All the products were characterized by Melting points, Elemental analyses C, H, and N, IR , 1 H-NMR and 13 C-NMR. The residual compounds were dissolved in 10 ml EtOAc and 5N HCl/iso-propanol was added in portions until pH 5 was reached. Several times the acid addition had to be stopped and the formed crystals removed by filtration. The salt was then recrystallised in iso-propanol.
- Trimetyl 2-(tert-butylamino)-6-(2-methoxy-2-oxoethyl)-4H-pyran-3,4,5-tricarboxylate:
Yellow oil, yield Solt 3.18 g, 73%, IR (KBr) (υ max /cm −1 ): 3456, 1744, 1737, 1721, 1683. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.34 (9H, s), 3.64 (3H, s), 3.69 (3H, s), 3.70 (3H, s), 3.75 (3H, s), 3.85 (2H, s), 4.55 (1H, s), 8.57 (1H, s). 13 C-NMR (100 MHz, CDCl 3 ): δ=30.34, 37.68, 37.70, 51.02, 52.17, 52.37, 52.56, 52.38, 72.28, 108.44, 154.48, 160.20, 165.94, 168.56, 169.38, 173.21. Anal calcd for C 18 H 25 NO 9 (399.4): C, 54.13; H, 6.31; N, 3.51; Found: C, 54.1; H, 6.3; N, 3.5.
- Trimetyl 2-(cyclohexylamino)-6-(2-methoxy-2-oxoethyl-4H-pyran-3,4,5-tricarboxylate:
White powder mp=116−118 ℃, yield Solt 3.23 g 67%, IR (KBr) (υ max /cm −1 ): 3504, 1744, 1730, 1724, 1686. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.25−2.38 (10H, m), 3.66 (3H, s), 3.75 (3H, s), 3.77 (3H, s), 3.80 (3H, s), 3.94 (2H, s), 4.17 (1H, m), 4.54 (1H, s), 8.39 (1H, br). 13 C-NMR (100 MHz, CDCl 3 ): δ=24.42, 25.37, 29.65, 33.30, 33.70, 37.48, 37.87, 48.64, 49.98, 50.93, 52.13, 52.31, 71.68, 108.53, 154.75, 156.91, 159.05, 168.59, 169.21, 173.21. Anal calcd for C 20 H 27 NO 9 (425.4): C, 56.47; H, 6.40; N, 3.29; Found: C, 56.5; H, 6.4; N, 3.3.
- Trimethyl 2-methoxycarbonylmethyl-6-(4-methoxyphenylamino)-4H-pyran-3,4,5-tricarboxylate:
Yellow crystal, mp=188−189 ℃, yield Solt 3.10 g, 69%, IR (KBr) (υ max /cm −1 ): 3455, 3012, 1744, 1737, 1728, 1683, 1672, 1612, 1511, 1452, 1253, 1050. 1 H-NMR (400 MHz, CDCl 3 ): δ=3.62 (3H, s), 3.67 (s, 3 H), 3.69 (3H, s), 3.70 (3H, s), 3.73 (3H, s), 3.85 (2H, s), 4.55 (1H, s), 7.18 (d, J =8.6 Hz, 2H), 7.28 (d, J =8.6 Hz, 2H), 8.52 (1H, s). 13 C-NMR (100 MHz, CDCl 3 ): δ=30.31, 36.98, 37.30, 50.96, 51.52, 52.31, 52.48, 72.28, 108.44, 120.82, 132.76, 144.25, 145.22, 154.48, 160.20, 165.94, 168.56, 169.38, 173.21. Anal calcd for C 21 H 23 NO 10 (449.4): C, 56.12; H, 5.16; N, 3.12; Found: C, 56.1; H, 5.2; N, 3.1.
- 3,4-Diethyl 5-methyl 2-(tert-butylamino)-6-(2-methoxy-2-oxoethyl)-4H-pyran-3,4,5-tricarboxylate:
Yellow oil, yield Solt 3.33 g 72%, IR (KBr) (υ max /cm −1 ): 3455, 1744, 1738, 1734, 1638. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.24 (3H, t, J =8 Hz), 1.31 (3H, t, J =8 Hz), 1.38 (9H, s), 3.74 (3H, s), 3.80 (3H, s), 3.98 (2H, s), 4.08−4.25 (4H, m), 4.56 (1H, s), 8.62 (1H, br). 13 C-NMR (100 MHz, CDCl 3 ): δ=14.10, 14.75, 30.34, 37.68, 37.89, 52.02, 52.31, 52.44, 59.84, 60.47, 72.47, 108.47, 154.19, 160.06, 166.89, 168.02, 169.57, 172.08. Anal calcd for C 20 H 29 NO 9 (427.5): C, 56.20; H, 6.84; N, 3.28; Found: C, 56.20; H, 6.8; N, 3.3.
- 3,4-Diethyl 5-methyl 2-(cyclohexylamino)-6-(2-methoxy-2-oxoethyl)-4H-pyran-3,4,5-tricarboxylate:
Yellow oil, yield Solt 3.38 g 69%, IR (KBr) ( υ max /cm −1 ): 3456, 1744, 1740, 1735, 1721. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.24 (3H, t, J =8 Hz), 1.30 (3H, t, J =8 Hz), 1.53−1.95(10H, m), 3.74 (3H, s), 3.79 (3H, s), 3.90 (2H, s), 4.03− 4.31 (5H, m), 4.55 (1H, s), 8.42 (1H, br). 13 C-NMR (100 MHz, CDCl 3 ): δ=14.12, 14.60, 22.37, 24.36, 24.37, 33.28, 33.71, 37.50, 37.93, 49.90, 52.06, 52.30, 59.36, 60.87, 71.73, 108.46, 154.53, 158.85, 166.08, 168.68, 169.00, 172.99. calcd for C 22 H 31 NO 9 (453.5): C, 58.27; H, 6.89; N, 3.09; Found: C, 58.3; H, 6.9; N, 3.1.
- 4,5-Diethyl 3-methyl 2-(methoxycarbonylmethyl)-6-(4-methoxy-phenylamino)-4H-pyran-3,4,5-tricarboxylate:
Yellow crystal, mp=173−175 ℃, yield Solt 3.44 g, 72%, IR (KBr) (υ max /cm −1 ): 3455, 3011, 1743, 1736, 1728, 1682, 1672, 1612, 1511, 1452, 1253, 1050. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.22 (3H, t, J =8 Hz), 1.30 (3H, t, J =8 Hz), 3.64 (3H, s), 3.67 (3 H, s), 3.70 (3H, s), 3.85 (2H, s), 4.10−4.25 (4H, m), 4.55 (1H, s), 7.15 (d, J =8.6 Hz, 2 H), 7.27 (d, J =8.6 Hz, 2H), 8.57 (1H, s). 13 C-NMR (100 MHz, CDCl 3 ): δ=14.21, 14.63, δ=30.34, 37.70, 38.42, 53.18, 51.76, 52.51, 52.38, 71.63, 108.31, 120.69, 132.64, 144.16, 145.01, 154.13, 160.16, 165.88, 168.50, 169.29, 173.08. Anal calcd for C 23 H 27 NO 10 (477.5): C, 57.86; H, 5.70; N, 2.93; Found: C, 58.0; H, 5.7; N, 2.9.
- 3,4-Di (tert-butyl) 5-methyl 2-(tert-butylamino)-6-(2-methoxy-2-oxoethyl)-4H-pyran-3,4,5-tricarboxylate:
Colourless crystal, mp=103−105 ℃, yield Solt 3.90 g 75%, IR (KBr) (υ max /cm −1 ): 3456, 1754, 1730, 1728, 1720. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.40 (9H, s), 1.43 (9H, s), 1.53 (9H, s), 3.76 (3H, s), 3.81 (3H, s), 3.89 (2H, s), 4.38 (1H, s), 8.55 (1H, br). 13 C-NMR (100 MHz, CDCl 3 ): δ=27.99, 28.54, 30.45, 37.70, 39.45, 51.92, 52.22, 52.32, 73.90, 79.31, 80.45, 108.78, 153.45, 159.71, 166.51, 166.75, 168.76, 172.24. Anal calcd for C 24 H 37 NO 9 (483.6): C, 59.61; H, 7.71; N, 2.90; Found: C, 59.6; H, 7.7; N, 2.9.
- 3,4-Di (tert-butyl) 5-methyl 2-(cyclohexylamino)-6-(2-methoxy-2-oxoethyl)-4H-pyran-3,4,5-tricarboxylate:
Yellow oil, yield Solt 3.82 g 70%, IR (KBr) (υ max /cm −1 ): 3488, 1747, 1740, 1728, 1686. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.25−1.93 (10H, m), 1.42 (9H, s), 1.50 (9H, s), 3.72(3H, s), 3.77 (3H, s), 3.86 (2H, s), 4.10 (1H, s), 4.35 (1H, s), 8.27 (1H, br). 13 C-NMR (100 MHz, CDCl 3 ): δ=27.96, 28.52, 24.62, 24.73, 25.42, 33.46, 33.93, 37.47, 39.46, 50.04, 51.88, 52.26, 73.16, 79.17, 80.45, 108.81, 153.73, 158.54, 166.44, 168.61, 168.80, 172.36. Anal calcd for C 26 H 39 NO 9 (509.6): C, 61.28; H, 7.71; N, 2.75; Found: C, 61.3; H, 7.7; N, 2.8.
- 4,5-Di-tert-butyl 3-methyl 2-(methoxycarbonyl methyl)-6-(4-methoxy-phenylamino)-4H-pyran-3,4,5-tricarboxylyte:
Yellow crystal, mp=162−163 ℃, yield Solt 3.41 g, 64%, IR (KBr) (υ max /cm −1 ): 3458, 3008, 1743, 1737, 1727, 1683, 1672, 1612, 1511, 1452, 1253, 1050. 1 H-NMR (400 MHz, CDCl 3 ): δ=1.40 (9H, s), 1.43 (9H, s), 3.69 (3H, s), 3.70 (3H, s), 3.75 (3H, s), 3.83 (2H, s), 4.52 (1H, s), 7.10 (d, J =8.6 Hz, 2 H), 7.22 (d, J =8.6 Hz, 2H), 8.59 (1H, s). 13 C-NMR (100 MHz, CDCl 3 ): δ=28.07, 28.61, 30.42, 37.02, 39.12, 51.17, 52.07, 52.26, 52.38, 73.38, 108.44, 120.82, 132.76, 144.25, 145.22, 154.48, 160.20, 165.94, 168.56, 169.38, 173.21. Anal calcd for C 27 H 35 NO 10 (533.57): C, 60.78; H, 6.61; N, 2.63; Found: C, 60.8; H, 6.6; N, 2.6.
- Preparation of Plates and Microbiological Assays
Inoculation of test bacteria (X. campestris pvs, P. syringae and P. carotovorum) was prepared by inoculating a loopful of organism in a 10 ml nutrient broth and incubated at 37 ℃ for 24 h each till a moderate turbidity was developed. 0.10 ml of this suspension was thoroughly mixed with 25 ml of nutrient agar medium in each. Presterilized Petri plates and was set aside. After the cooling, the seeded agar plate was used for testing compounds by disc diffusion method. The sterilized paper discs were dipped in each compound solution. These discs were placed in the plates at equidistant. The central disc without any compound was taken as control. The petri plates then incubated at 37 ℃ for 24 h. After the recommended period, zones of inhibition were measured. After solidification of medium, 0.10 ml of spore suspension was spread by sterilized spreader in a specific zone. The compounds were dissolved in DMSO solvent in 200 ppm concentration. The paper discs were dipped in each compound solution for 5 min. Then these paper discs were placed equidistant in the plates. The central disc was dipped in DMSO solvent without compound was used as control. These Petri plates were kept for incubation period at 28 ℃ for 3 days. After the completion of recommended period, the zones of inhibition were measured ( 3 ).
RESULTS AND DISCUSSION
In continuation, we have investigated the synthesis of 2-amino-4 H -pyran-3,4,5-tricarboxylate derivatives in the presence of BF 3 .SiO 2 via condensation of alkylisocyanides with actylenic esters and dimethyl acetone-1,3-dicarboxylate affords highly functionalized compound ( 2 ).
Herein, we report that BF 3 .SiO 2 is an efficient catalyst for the synthesis of 2-amino-4 H -pyran-3,4,5-tricarboxylate derivatives. The reaction of Diethyl 1,3-acetonedicarboxylate (10 mmol, 1.50 ml) with diethyl acetylene dicarboxylate (10 mmol, 1.67 ml) and 4-methoxyphenyl isocyanide (10 mmol, 1.33 g) was investigated for optimization of the reaction conditions ( 1 and 1 ). The reaction revealed that the best conditions were in H 2 O at room temperature.
PPT Slide
Lager Image
Synthesis of 4,5-diethyl 3-methyl 2-(methoxycarbonylmethyl)-6-(4-methoxy-phenylamino)-4H-pyran-3,4,5-tricarboxylate
PPT Slide
Lager Image
aIsolated yield
PPT Slide
Lager Image
Synthesis of 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-one derivativesaviaScheme2
PPT Slide
Lager Image
aThe dimethyl acetone-1,3-dicarboxylate (10 mmol, 1.82 ml) and acetylene dicarboxylate (10 mmol) in the presence of (0.32 g) of freshly prepared 37% BF3.SiO2 in H2O at room temperature. bAll the products were characterized by IR and 1H-NMR. cIsolated yield.
Dimethyl acetone-1,3-dicarboxylate with dimethyl or diethyl acetylene dicarboxylate and various isocyanide were used as substrates for the synthesis of 2-amino-4 H -pyran-3,4,5-tricarboxylate derivatives derivatives in H 2 O at room temperature ( 2 and 2 ).
We have synthesized a novel class 2-amino-4 H -pyran derivative as potential antibacterial agents. In vitro antibacterial assay was performed against X. campestris pvs, P. syringae and P. carotovorum by using the disc diffusion method. 27, 28 The results obtained as zone of inhibition (mm) are presented in 3 . Tetracycline was used as standard drugs for the assay. The concentration used for the test com-pounds and that of the standard drugs remains the same. It is observed from Table 1 that 2-amino-4 H -pyran-3,4,5-tricarboxylate derivative have exhibited moderate activity. When 2-amino-4 H -pyran-3,4,5-tricarboxylate derivatives were salt compound, there are high enhancement in the activity and solubility in water. Further, these functionalities were substituted with various groups like 3,4,5-tricarboxylate and 2-methoxy-2-oxoethyl since in the earlier studies it has been shown that the presence of one or more of the aforesaid would lead to the improvement of the activity.
Analytical and antibacterial activity of compounds
PPT Slide
Lager Image
Analytical and antibacterial activity of compounds
CONCLUSION
In conclusion, the reactions of alkyl isocyanides with electron deficient acetylenic esters in the presence of dimethyl acetone-1,3-dicarboxylate provides a simple onepot entry in to the synthesis of poly functional 4 H -pyran derivatives of potential synthetic interest. All synthesized compounds have shown good activity against the pathogenic bacteria.
Acknowledgements
Financial support for this work by the Research Council of University of Jiroft is gratefully acknowledged. And the publication cost of this paper was supported by the Korean Chemical Society.
References
Wilson K. , Clark J. H. 1998 Synthesis of a Novel Supported Solid Acid BF3Catalyst Chem. Commun. 2135 -
Klapotke T. M. , Mc Monagle F. , Spence R. R. , Winfield J. M. 2006 γ-Alumina-Supported Boron Trifluoride: Catalysis, Radiotracer Studies and Computations J. Fluorine. Chem. 127 1446 -    DOI : 10.1016/j.jfluchem.2006.05.010
Sadegi B. , Mirjalili B. F. , Hashemi M. M. 2008 BF3·SiO2: An Efficient Reagent System for the One-Pot Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles Tetrahedron Lett 49 2575 -    DOI : 10.1016/j.tetlet.2008.02.100
Mirjalili B. F. , Bamoniri A. , Akbari A. 2008 BF3·SiO2: An Efficient Alternative for the Synthesis of 14-Aryl or Alkyl-14H-dibenzo[a,j]xanthenes Tetrahedron Lett 49 6454 -    DOI : 10.1016/j.tetlet.2008.08.101
Sadegi B. , Mirjalili B. F. , Hashememi M. M. 2008 BF3·SiO2: An Efficient Heterogeneous Alternative for Regio-Chemo and Stereoselective Claisen-schmidt Condensation J. Iran. Chem. Soc. 5 (4) 694 -    DOI : 10.1007/BF03246151
Boodhoo K. V. K. , Dunk W. A. E. , Vicevic M. , Jachuck R. J. , Sage V. , Macquarrie D. J. , Clark J. H. 2006 Classical Cationic Polymerisation of Styrene in a Spinning Disc Reactor Using Silica Supported BF3Catalyst J. Appl. Polym. Sci. 101 (1) 8 -    DOI : 10.1002/app.22758
Dindulkar S. D. , Parthiban P. , Jeong Y. T. 2012 BF3·SiO2is a Simple and Efficient Lewis Acid Catalyst for the One-Pot Synthesis of Polyfunctionalized Piperidin-4-ones Monatsh. Chem. 143 113 -    DOI : 10.1007/s00706-011-0576-5
Reddy M. V. , Dindulkar S. D. , Jeong Y. T. 2011 BF3·SiO2- Catalyzed One-Pot Synthesis of α-Aminophosphonates in Ionic Liquid and Neat Conditions Tetrahedron Lett 52 4764 -    DOI : 10.1016/j.tetlet.2011.07.027
Mirjalili B. F. , Bamoniri A. , Akbari A 2011 Nano-BF3·SiO2: a Reusable and Eco-friendly Catalyst for Synthesis of Quinoxalines Chem. Heterocycl. Comp. 47 (4) 487 -    DOI : 10.1007/s10593-011-0785-1
Mirjalili B. F. , Bamoniri A. , Akbari A. 2011 One-pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones (thiones) Promoted by Nano-BF3·SiO2 J. Iran. Chem. Soc. 8 135 -    DOI : 10.1007/BF03254290
Rho H. S. , Baek H. S. , You J. W. , Kim S. , Lee J. Y. , Kim D. H. , Chang I. S. 2007 Bull. Korean Chem. Soc. 28 (3) 471 -    DOI : 10.5012/bkcs.2007.28.3.471
Li D.-H. , Cai S.-X. , Tian L. , Lin Z.-J. , Zhu T.-J. , Fang Y.-C. , Liu P.-P. , Gu Q.-Q. , Zhu W.-M. 2007 Arch. Pharm. Res. 30 (9) 1051 -    DOI : 10.1007/BF02980236
Wang T.-S. , Wang S.-Q. , Xiao D.-L. 2012 J. Med. Plants Res. 6 (26) 4259 -
Larget R. , Lockhart B. , Renard P. , Largeron M. 2000 Biorg. Med. Chem. Lett. 10 835 -    DOI : 10.1016/S0960-894X(00)00110-4
Groweiss A. , Cardellins J. H. , Boyd M. R. 2000 J. Nat. Prod. 63 1537 -    DOI : 10.1021/np000175m
Deng Y. , Lee J. P. , Ramamonjy M. T. , Synder J. K. , Des Etages S. A. , Kanada D. , Synder M. P. , Turner C. J. 2000 J. Nat. Prod. 63 1082 -    DOI : 10.1021/np000054m
Khan I. A. , Avery M. A. , Burandt C. L. , Goins D. K. , Mikell J. R. , Nash T. E. , Azadega A. , Walker L. A. 2000 J. Nat. Prod. 63 1414 -    DOI : 10.1021/np000010d
Mori K. , Audran G. , Monti H. 1998 Synlett 259 -
Pietta P. J. J. 2000 Nat. Prod. 63 1035 -    DOI : 10.1021/np9904509
Nasiri F. , Nazem F. , Pourdavaie K. 2007 Mol. Divers. 11 101 -    DOI : 10.1007/s11030-007-9064-6
Park E.-J. , Gray P. M. , Oh S.-W. , Kronenberg J. , Kang D.-H. 2008 J. Food. Science 73 (6) M278 -    DOI : 10.1111/j.1750-3841.2008.00793.x
Toth I. K. , Bell K. S. , Holeva, M. C., Birch P. R. J. 2003 Molecular Plant Pathology 4 (1) 17 -    DOI : 10.1046/j.1364-3703.2003.00149.x
Yang J. W. , Yi H.-S. , Kim H. , Lee B. , Lee S. , Ghim S.-Y. , Ryu C.-M. 2011 J. Ecology 99 (1) 46 -    DOI : 10.1111/j.1365-2745.2010.01756.x
Boch J. , Bonas U. 2010 Annual Review of Phytopathology 48 419 -    DOI : 10.1146/annurev-phyto-080508-081936
Ivanovic Z. , Zivkovic S. , Starovic M. , Josic D. , Stankovic S. , Gavrilovic V. 2009 Arch. Biol. Sci. 61 (4) 863 -    DOI : 10.2298/ABS0904863I
Rodrigo J. 2000 Sci. Hortic. 85 (3) 155 -    DOI : 10.1016/S0304-4238(99)00150-8
Lemriss S. , Marquet B. , Ginestet H. , Lefeuvre L. , Fassouane A. , Boiron P. 2003 J. Mycol. Med. 13 189 -
Rahman A. , Choudhary M. I. , Thomsen W. J. 2001 Bioassay Techniques for Drug Development Harwood Academic Publishers Amsterdam