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Polyvinylpolypyrrolidone–bromine complex: Mild and efficient polymeric reagent for bromination of activated aromatic compounds
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Chinese Chemical Letters 22 (2011) 13–17 www.elsevier.com/locate/cclet
Polyvinylpolypyrrolidone–bromine complex: Mild and efficient polymeric reagent for bromination of activated aromatic compounds Masoud Mokhtary a,*, Moslem M. Lakouraj b a
Department of Chemistry, Islamic Azad University-Ayatollah Amoli Branch, P.O. Box 678, Amol, Iran b Department of Organic-Polymer Chemistry, Mazandaran University, Babolsar 47416, Iran Received 13 April 2010
Abstract Mild and efficient method for bromination of electron-rich aromatic compounds is described using polyvinylpolypyrrolidone– bromine complex (PVPP–Br2). The reaction proceeded smoothly with phenols and N,N-alkylated amines to afford the corresponding monobrominated product in good yields at ambient temperature. # 2010 Masoud Mokhtary. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Polyvinylpolypyrrolidone; Phenols; Bromination; Reagent
Brominated arenes are a useful class of intermediates in the synthesis of a wide variety of biologically active compounds. Aeroplysinin-1 (1) an antimicrobial metabolite from sponges [1], 14-debromoprearaplysillin (2) from the marine sponge Druinella purpurea [2], and the antimicrobial compound 2-(20 -bromophenoxy)-3,4,5,6-tetrabromophenol (3) from the spong Dysidea [3] are some example of brominated phenolic derivatives of marine natural products with important biological activities (Fig. 1). The traditional direct bromination of aromatic compounds using elemental bromine suffers the major drawbacks due to toxicity, corrosive, poor regioselectivity, overbromination and the products of the reactions are generally complicated and contaminated with by-products [4,5]. There are some alternative bromination reagents such as PyHBr3 [6], DBUHBr3 [7], Br2–Lewis acids [8], Br2–silica or clay supported ZnBr2 [9], NBS–HCl [10], Bu4NBr/ HNO3 [11], CuBr2 [12], Br2/CTAB/Cs2.5H0.5PW [13], Br2/dioxane [14], KBr/BTPPPD [15], PBC [16], zeolite/KBr/ H2O2 [17], KBr/BTPPMS [18], ZrBr4/diaziene [19], IQBC [20] and [BMPy]Br3 [21]. However, some of these methods involve drastic reaction conditions, costly reagents, hazardous mineral acids which can lead to separation difficulties and toxic and corrosive wastes. Polymer supported catalyst and reagent have become popular in organic synthesis over the past decades. The high catalytic activity, low toxicity, stability, their recyclability, and environmentally safe condition make the use of polymer supported reagent attractive alternatives to conventional reagents. Also, the application of polymer supports as reagent and catalyst has received special attention, due to easy work up of reaction products and some selectivity which is undoubtedly attractive features of this methodology [22].
* Corresponding author. E-mail address: [email protected] (M. Mokhtary). 1001-8417/$ – see front matter # 2010 Masoud Mokhtary. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2010.06.002
[()TD$FIG] 14
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
Fig. 1. Examples of marine natural products with important biological activites.
Poly(vinylpyrrolidone) displays a strong binding affinity toward small molecules [23], its iodine complex, povidon–iodine, is widely used as an anti-infective agent in clinical treatments [24]. In continuation to our research on bromination of alkenes and oxidation of alcohols with linear poly(vinylpyrrolidone)–bromine complex [25], and oxidative deprotection of silyl ethers [26], herein, we found that PVPP–Br2, can be used for monobromination of activated aromatic compounds especially phenols. To extend the synthetic utility of this reagent as an environmentally safe brominating agent, our effort has been directed toward bromination of activated aromatic compound especially phenols with good yields at room temperature (Scheme 1). The PVPP–Br2 complex is insoluble, non-volatile polymeric reagent and retains its activity after several months of storage. As shown in Table 1, a variety of activated aromatic compounds were treated with PVPP–Br2 complex in dichloromethane as a solvent at room temperature. Methyl substituted phenols (Table 1, entries 1–5) were smoothly reacted with PVPP–Br2 reagent and gave corresponding monobrominated products in good yields. The bulky substituted phenols were treated with PVPP–Br2 reagent to afforded their monobrominated products in good yields (Table 1, entries 6 and 7). When electron withdrawing substituted phenol applied in this reaction moderate yield of the corresponding brominated product was achieved (Table 1, entry 8). Some other aromatic compounds such as bnaphtol and anisol were also subjected to these reaction conditions, and the corresponding monobrominated products were obtained in good yields (Table 1, entries 9 and 10). We have also studied the bromination of activated anilines such as N,N-dimethyl and N,N-diethyl aniline in the presence of this polymeric brominated reagent. The results show that bromination proceded efficiently and afforded their P-bromo derivatives in good yields (Table 1, entries 11 and 12). In the bromination of aniline a low yield of the corresponding monobrominated isomer were formed. We believe that the high reactivity of aniline toward electrophilic substitution reactions resulted in uncontrolled by-product formation in this reaction. 1. Experimental Melting points were recorded on electro-thermal melting point apparatus. The NMR spectra were recorded in CDCl3 with TMS as an internal standard on Bruker WM 500 NMR spectrometer. IR spectra were determined on a SP1100, P-UV-Com instrument. Polyvinylpolypyrrolidone (PVPP) was purchased from Fluka. Purity determination of the products was accomplished by TLC on silica gel poly gram SIL G/UV 254 plates. Products were identified by the comparison of their Mp, IR and NMR spectra, with those reported for authentic samples. 1.1. Preparation of polyvinylpolypyrrolidone–bromine complex (PVPP–Br2) To a suspension of polyvinylpolypyrrolidone (PVPP) 4 g in CH2Cl2 (25 mL), a solution of bromine (5 mL) in
[()TD$FIG]CH2Cl2 (15 mL) was added drop wise and the mixture stirred for 0.5 h at room temperature. The resulting dark-orange
Scheme 1.
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
15
Table 1 Bromination of electron-rich aromatic rings by PVPP–Br2 complex. Entry
1
Substrate
Producta
Time/min
Yield/%b
M.P. (8C) [Ref.]
[TD$INLE]
30
90
77–79 [27]
[TD$INLE]
2
[TD$INLE]
[TD$INLE]
30
88
85–87 [27]
3
[TD$INLE] [TD$INLE]
30
87
82–84 [28]
[TD$INLE]
30
80
55–57 [27]
30
90
61–63 [27]
30
90
81–83 [29]
[TD$INLE]
4
[TD$INLE] [TD$INLE]
5
[TD$INLE]
[TD$INLE]
[TD$INLE] [TD$INLE]
30
86
49–51 [30]
[TD$INLE]
45
70
67–69 [31]
[TD$INLE]
30
95
83–85 [27]
60
76
Liq.
6
7
[TD$INLE] 8
[TD$INLE]
9
[TD$INLE]
[TD$INLE]
11
[TD$INLE] [TD$INLE]
30
80
54–56 [27]
12
[TD$INLE]
[TD$INLE]
30
80
31–33 [27]
10
a
All of the products were identified by comparing melting point and 1H NMR with those of authentic samples reported in the literature. Yields refer to isolated products.
b
[()TD$FIG] 16
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
Scheme 2.
resin was filtered and washed with CH2Cl2 (2 10 mL), finally dried in desiccator to give stable and non-hygroscopic powder. The IR spectra shows nC O of polyvinylpolypyrrolidone–bromine complex at 1654 cm1 while nC O of polyvinylpolypyrrolidone is about 1668 cm1. Capacity of the reagent was determined by idometric titration and found to be 2.85 mmol of bromine per gram of polymeric reagent.
1.2. General procedure for bromination of aromatic compounds To a suspension of aromatic compound (1 mmol) in dichloromethane (10 mL) in a 25 mL round-bottomed flask, PVPP–Br2 (1 mmol, 0.35 g) was added. The reaction mixture stirred for 30-60 minute at room temperature. After completion of the reaction by TLC (carbon tetrachloride/n-hexane 8:2). The filtrate was poured into a 100 mL separating funnel, washed with 2 25 mL water. Finally, the organic layer was dried over sodium sulfate and filtereted and solvent was concentrated in a rotary evaporator. Further purification performed through silica gel column chromatography. All of the products were identified by comparing melting point and 1H NMR with those of authentic samples reported in the literature. An interesting feature of this method is that the spent resin can be regenerated at the end of the reaction after washing with organic solvent and back to the starting polyvinylpolypyrrolidone–bromine complex and can be used several times without losing its activity as depicted in Scheme 2. In conclusion, we developed clean and versatile method for the ring bromination of active aromatic compounds using polyvinylpolypyrrolidone–bromine complex at room temperature. The mild conditions, simple experimental procedure, good yields and reusability of the spent reagent are notable advantages of the method. In addition, this method is suitable both for preparative and industrial usage because of cheapness, biocompatibility and recyclability of the polyvinylpolypyrrolidone as a safe polymer support.
1.3. Selected spectroscopic data 4-Bromo-2,6-dimethylphenol (entry 1): 1H NMR (CDCl3): d 2.2 (s, 6H), 4.64 (bs, 1H), 7.08 (s, 2H). 4-Bromo-3-methylphenol (entry 5): 1H NMR (CDCl3): d 2.31 (s, 3H), 5.28 (bs, 1H), 6.54 (dd, 1H, J = 8.55, 2.81 Hz), 6.72 (d, 1H, J = 2.81 Hz), 7.32 (d, 1H, J = 8.55 Hz). 4-Bromo-2,6-ditert-butylphenol (entry 6): 1H NMR (CDCl3): d 1.5 (s, 18H), 5.24 (bs, 1H), 7.25 (s, 2H). 2-Bromo-4-tert-butylphenol (entry 7): 1H NMR (CDCl3): d 1.33 (s, 9H), 5.44 (bs, 1H), 6.98 (d, 1H, J = 8.5 Hz), 7.27(dd, 1H, J = 2.2, 8.5 Hz), 7.48 (d, 1H, J = 2.2 Hz). 4-Bromo-N,N-diethylaniline (entry 12): 1H NMR (CDCl3): d 1.14 (t, 6H, J = 7.1 Hz), 3.31 (q, 4H, J = 7.1 Hz), 6.54 (d, 2H, J = 8.8 Hz), 7.65 (d, 2H, J = 8.9 Hz).
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
17
Acknowledgments We are thankful to the Research Council of Islamic Azad University-Ayatollah Amoli Branch for financial support of this work. References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31]
M. Nieder, L. Hager, Arch. Biochem. Biophys. 240 (1985) 121. M.D. James, H.B. Kunze, D.J. Faulkner, J. Nat. Prod. 54 (1991) 1137. J. Salva, J. Faulkner, J. Nat. Prod. 53 (1990) 757. K. Smith, Advances in Organobromine Chemistry II, Elsevier, New York, 1995, pp. 4–64. W.A.L. Vanotterlo, J.P. Michael, M.A. Fernandes, et al. Tetrahedron Lett. 45 (2004) 5091. L.F. Fieser, M. Fieser, Reagents for Organic Synthesis, Wiley, New York, 1967, p. 967. H.A. Muathen, J. Org. Chem. 57 (1992) 2740. H. Schmid, Helv. Chem. Acta 29 (1946) 1144. J.H. Clark, J.C. Ross, D.J. Macquarrie, et al. Chem. Commun. (1997) 1203. B. Andersh, D.L. Murphy, R.J. Olson, Synth. Commun. 30 (2000) 2091. A.V. Joshi, M. Baidossi, S. Mukhopadhyay, et al. Org. Process Res. Dev. 8 (2004) 568. S. Bhatt, S.K. Nayak, Synth. Commun. 37 (2007) 1381. H. Firouzabadi, N. Iranpoor, K. Amini, J. Mol. Catal. A 195 (2003) 289. S.K. Chaudhuri, S. Roy, M. Saha, et al. Synth. Commun. 37 (2007) 579. H. Tajik, I. Mohammadpoor Baltork, J. Albadi, Synth. Commun. 37 (2007) 323. S.B. Patwari, M.A. Baseer, Y.B. Vibhute, et al. Tetrahedron Lett. 44 (2003) 4893. N. Narender, K.V.V. Krishna Mohan, R.V. Reddy, et al. J. Mol. Catal. A 192 (2003) 73. H. Adibi, A.R. Hajipour, M. Hashemi, Tetrahedron Lett. 48 (2007) 1255. T. Stropnik, S. Bombek, M. Kocˆerar, S. Polanc, Tetrahedron Lett. 49 (2008) 1729. S.V. Khansol, S.B. patwari, S.B. Patwari, et al. Chin. Chem. Lett. 20 (2009) 256. S.P. Borikar, T. daniel, V. Paul, Tetrahedron Lett 50 (2009) 1007. S.V. Ley, I.R. Baxendale, R.N. Bream, et al. J. Chem. Soc., Perkin Trans. 1 (2000) 3815. C. Liu, S. Cui, Z. Wang, X. Zhang, J. Phys. Chem. B 109 (2005) 14807. G. Ester, E.H. Immergut, J. Am. Chem. Soc. 76 (1954) 1393. M.M. Lakouraj, M. Tajbakhsh, M. Mokhtary, J. Chem. Res. (2005) 481. M.M. Lakouraj, M. Mokhtary, Lett. Org. Chem. 4 (2007) 64. J. Buckingham, S.M. Donaghy, Dictionary of Organic Compounds, sixth ed., Chapman and Hall, London, 1982. F. Kaiser, L. Schwink, J. Velder, H.G. Schmalz, Tetrahedron 59 (2003) 3201. T. Ooi, K. Maruoka, H. Yamamoto, Org. Synth. Coll. 9 (1942) 356. B. Jones, J. Chem. Soc. (1941) 358. D.L. Fox, E.E. Turner, J. Chem. Soc. (1930) 1853.
Chinese Chemical Letters 22 (2011) 13–17 www.elsevier.com/locate/cclet
Polyvinylpolypyrrolidone–bromine complex: Mild and efficient polymeric reagent for bromination of activated aromatic compounds Masoud Mokhtary a,*, Moslem M. Lakouraj b a
Department of Chemistry, Islamic Azad University-Ayatollah Amoli Branch, P.O. Box 678, Amol, Iran b Department of Organic-Polymer Chemistry, Mazandaran University, Babolsar 47416, Iran Received 13 April 2010
Abstract Mild and efficient method for bromination of electron-rich aromatic compounds is described using polyvinylpolypyrrolidone– bromine complex (PVPP–Br2). The reaction proceeded smoothly with phenols and N,N-alkylated amines to afford the corresponding monobrominated product in good yields at ambient temperature. # 2010 Masoud Mokhtary. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Polyvinylpolypyrrolidone; Phenols; Bromination; Reagent
Brominated arenes are a useful class of intermediates in the synthesis of a wide variety of biologically active compounds. Aeroplysinin-1 (1) an antimicrobial metabolite from sponges [1], 14-debromoprearaplysillin (2) from the marine sponge Druinella purpurea [2], and the antimicrobial compound 2-(20 -bromophenoxy)-3,4,5,6-tetrabromophenol (3) from the spong Dysidea [3] are some example of brominated phenolic derivatives of marine natural products with important biological activities (Fig. 1). The traditional direct bromination of aromatic compounds using elemental bromine suffers the major drawbacks due to toxicity, corrosive, poor regioselectivity, overbromination and the products of the reactions are generally complicated and contaminated with by-products [4,5]. There are some alternative bromination reagents such as PyHBr3 [6], DBUHBr3 [7], Br2–Lewis acids [8], Br2–silica or clay supported ZnBr2 [9], NBS–HCl [10], Bu4NBr/ HNO3 [11], CuBr2 [12], Br2/CTAB/Cs2.5H0.5PW [13], Br2/dioxane [14], KBr/BTPPPD [15], PBC [16], zeolite/KBr/ H2O2 [17], KBr/BTPPMS [18], ZrBr4/diaziene [19], IQBC [20] and [BMPy]Br3 [21]. However, some of these methods involve drastic reaction conditions, costly reagents, hazardous mineral acids which can lead to separation difficulties and toxic and corrosive wastes. Polymer supported catalyst and reagent have become popular in organic synthesis over the past decades. The high catalytic activity, low toxicity, stability, their recyclability, and environmentally safe condition make the use of polymer supported reagent attractive alternatives to conventional reagents. Also, the application of polymer supports as reagent and catalyst has received special attention, due to easy work up of reaction products and some selectivity which is undoubtedly attractive features of this methodology [22].
* Corresponding author. E-mail address: [email protected] (M. Mokhtary). 1001-8417/$ – see front matter # 2010 Masoud Mokhtary. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2010.06.002
[()TD$FIG] 14
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
Fig. 1. Examples of marine natural products with important biological activites.
Poly(vinylpyrrolidone) displays a strong binding affinity toward small molecules [23], its iodine complex, povidon–iodine, is widely used as an anti-infective agent in clinical treatments [24]. In continuation to our research on bromination of alkenes and oxidation of alcohols with linear poly(vinylpyrrolidone)–bromine complex [25], and oxidative deprotection of silyl ethers [26], herein, we found that PVPP–Br2, can be used for monobromination of activated aromatic compounds especially phenols. To extend the synthetic utility of this reagent as an environmentally safe brominating agent, our effort has been directed toward bromination of activated aromatic compound especially phenols with good yields at room temperature (Scheme 1). The PVPP–Br2 complex is insoluble, non-volatile polymeric reagent and retains its activity after several months of storage. As shown in Table 1, a variety of activated aromatic compounds were treated with PVPP–Br2 complex in dichloromethane as a solvent at room temperature. Methyl substituted phenols (Table 1, entries 1–5) were smoothly reacted with PVPP–Br2 reagent and gave corresponding monobrominated products in good yields. The bulky substituted phenols were treated with PVPP–Br2 reagent to afforded their monobrominated products in good yields (Table 1, entries 6 and 7). When electron withdrawing substituted phenol applied in this reaction moderate yield of the corresponding brominated product was achieved (Table 1, entry 8). Some other aromatic compounds such as bnaphtol and anisol were also subjected to these reaction conditions, and the corresponding monobrominated products were obtained in good yields (Table 1, entries 9 and 10). We have also studied the bromination of activated anilines such as N,N-dimethyl and N,N-diethyl aniline in the presence of this polymeric brominated reagent. The results show that bromination proceded efficiently and afforded their P-bromo derivatives in good yields (Table 1, entries 11 and 12). In the bromination of aniline a low yield of the corresponding monobrominated isomer were formed. We believe that the high reactivity of aniline toward electrophilic substitution reactions resulted in uncontrolled by-product formation in this reaction. 1. Experimental Melting points were recorded on electro-thermal melting point apparatus. The NMR spectra were recorded in CDCl3 with TMS as an internal standard on Bruker WM 500 NMR spectrometer. IR spectra were determined on a SP1100, P-UV-Com instrument. Polyvinylpolypyrrolidone (PVPP) was purchased from Fluka. Purity determination of the products was accomplished by TLC on silica gel poly gram SIL G/UV 254 plates. Products were identified by the comparison of their Mp, IR and NMR spectra, with those reported for authentic samples. 1.1. Preparation of polyvinylpolypyrrolidone–bromine complex (PVPP–Br2) To a suspension of polyvinylpolypyrrolidone (PVPP) 4 g in CH2Cl2 (25 mL), a solution of bromine (5 mL) in
[()TD$FIG]CH2Cl2 (15 mL) was added drop wise and the mixture stirred for 0.5 h at room temperature. The resulting dark-orange
Scheme 1.
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
15
Table 1 Bromination of electron-rich aromatic rings by PVPP–Br2 complex. Entry
1
Substrate
Producta
Time/min
Yield/%b
M.P. (8C) [Ref.]
[TD$INLE]
30
90
77–79 [27]
[TD$INLE]
2
[TD$INLE]
[TD$INLE]
30
88
85–87 [27]
3
[TD$INLE] [TD$INLE]
30
87
82–84 [28]
[TD$INLE]
30
80
55–57 [27]
30
90
61–63 [27]
30
90
81–83 [29]
[TD$INLE]
4
[TD$INLE] [TD$INLE]
5
[TD$INLE]
[TD$INLE]
[TD$INLE] [TD$INLE]
30
86
49–51 [30]
[TD$INLE]
45
70
67–69 [31]
[TD$INLE]
30
95
83–85 [27]
60
76
Liq.
6
7
[TD$INLE] 8
[TD$INLE]
9
[TD$INLE]
[TD$INLE]
11
[TD$INLE] [TD$INLE]
30
80
54–56 [27]
12
[TD$INLE]
[TD$INLE]
30
80
31–33 [27]
10
a
All of the products were identified by comparing melting point and 1H NMR with those of authentic samples reported in the literature. Yields refer to isolated products.
b
[()TD$FIG] 16
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
Scheme 2.
resin was filtered and washed with CH2Cl2 (2 10 mL), finally dried in desiccator to give stable and non-hygroscopic powder. The IR spectra shows nC O of polyvinylpolypyrrolidone–bromine complex at 1654 cm1 while nC O of polyvinylpolypyrrolidone is about 1668 cm1. Capacity of the reagent was determined by idometric titration and found to be 2.85 mmol of bromine per gram of polymeric reagent.
1.2. General procedure for bromination of aromatic compounds To a suspension of aromatic compound (1 mmol) in dichloromethane (10 mL) in a 25 mL round-bottomed flask, PVPP–Br2 (1 mmol, 0.35 g) was added. The reaction mixture stirred for 30-60 minute at room temperature. After completion of the reaction by TLC (carbon tetrachloride/n-hexane 8:2). The filtrate was poured into a 100 mL separating funnel, washed with 2 25 mL water. Finally, the organic layer was dried over sodium sulfate and filtereted and solvent was concentrated in a rotary evaporator. Further purification performed through silica gel column chromatography. All of the products were identified by comparing melting point and 1H NMR with those of authentic samples reported in the literature. An interesting feature of this method is that the spent resin can be regenerated at the end of the reaction after washing with organic solvent and back to the starting polyvinylpolypyrrolidone–bromine complex and can be used several times without losing its activity as depicted in Scheme 2. In conclusion, we developed clean and versatile method for the ring bromination of active aromatic compounds using polyvinylpolypyrrolidone–bromine complex at room temperature. The mild conditions, simple experimental procedure, good yields and reusability of the spent reagent are notable advantages of the method. In addition, this method is suitable both for preparative and industrial usage because of cheapness, biocompatibility and recyclability of the polyvinylpolypyrrolidone as a safe polymer support.
1.3. Selected spectroscopic data 4-Bromo-2,6-dimethylphenol (entry 1): 1H NMR (CDCl3): d 2.2 (s, 6H), 4.64 (bs, 1H), 7.08 (s, 2H). 4-Bromo-3-methylphenol (entry 5): 1H NMR (CDCl3): d 2.31 (s, 3H), 5.28 (bs, 1H), 6.54 (dd, 1H, J = 8.55, 2.81 Hz), 6.72 (d, 1H, J = 2.81 Hz), 7.32 (d, 1H, J = 8.55 Hz). 4-Bromo-2,6-ditert-butylphenol (entry 6): 1H NMR (CDCl3): d 1.5 (s, 18H), 5.24 (bs, 1H), 7.25 (s, 2H). 2-Bromo-4-tert-butylphenol (entry 7): 1H NMR (CDCl3): d 1.33 (s, 9H), 5.44 (bs, 1H), 6.98 (d, 1H, J = 8.5 Hz), 7.27(dd, 1H, J = 2.2, 8.5 Hz), 7.48 (d, 1H, J = 2.2 Hz). 4-Bromo-N,N-diethylaniline (entry 12): 1H NMR (CDCl3): d 1.14 (t, 6H, J = 7.1 Hz), 3.31 (q, 4H, J = 7.1 Hz), 6.54 (d, 2H, J = 8.8 Hz), 7.65 (d, 2H, J = 8.9 Hz).
M. Mokhtary, M.M. Lakouraj / Chinese Chemical Letters 22 (2011) 13–17
17
Acknowledgments We are thankful to the Research Council of Islamic Azad University-Ayatollah Amoli Branch for financial support of this work. References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31]
M. Nieder, L. Hager, Arch. Biochem. Biophys. 240 (1985) 121. M.D. James, H.B. Kunze, D.J. Faulkner, J. Nat. Prod. 54 (1991) 1137. J. Salva, J. Faulkner, J. Nat. Prod. 53 (1990) 757. K. Smith, Advances in Organobromine Chemistry II, Elsevier, New York, 1995, pp. 4–64. W.A.L. Vanotterlo, J.P. Michael, M.A. Fernandes, et al. Tetrahedron Lett. 45 (2004) 5091. L.F. Fieser, M. Fieser, Reagents for Organic Synthesis, Wiley, New York, 1967, p. 967. H.A. Muathen, J. Org. Chem. 57 (1992) 2740. H. Schmid, Helv. Chem. Acta 29 (1946) 1144. J.H. Clark, J.C. Ross, D.J. Macquarrie, et al. Chem. Commun. (1997) 1203. B. Andersh, D.L. Murphy, R.J. Olson, Synth. Commun. 30 (2000) 2091. A.V. Joshi, M. Baidossi, S. Mukhopadhyay, et al. Org. Process Res. Dev. 8 (2004) 568. S. Bhatt, S.K. Nayak, Synth. Commun. 37 (2007) 1381. H. Firouzabadi, N. Iranpoor, K. Amini, J. Mol. Catal. A 195 (2003) 289. S.K. Chaudhuri, S. Roy, M. Saha, et al. Synth. Commun. 37 (2007) 579. H. Tajik, I. Mohammadpoor Baltork, J. Albadi, Synth. Commun. 37 (2007) 323. S.B. Patwari, M.A. Baseer, Y.B. Vibhute, et al. Tetrahedron Lett. 44 (2003) 4893. N. Narender, K.V.V. Krishna Mohan, R.V. Reddy, et al. J. Mol. Catal. A 192 (2003) 73. H. Adibi, A.R. Hajipour, M. Hashemi, Tetrahedron Lett. 48 (2007) 1255. T. Stropnik, S. Bombek, M. Kocˆerar, S. Polanc, Tetrahedron Lett. 49 (2008) 1729. S.V. Khansol, S.B. patwari, S.B. Patwari, et al. Chin. Chem. Lett. 20 (2009) 256. S.P. Borikar, T. daniel, V. Paul, Tetrahedron Lett 50 (2009) 1007. S.V. Ley, I.R. Baxendale, R.N. Bream, et al. J. Chem. Soc., Perkin Trans. 1 (2000) 3815. C. Liu, S. Cui, Z. Wang, X. Zhang, J. Phys. Chem. B 109 (2005) 14807. G. Ester, E.H. Immergut, J. Am. Chem. Soc. 76 (1954) 1393. M.M. Lakouraj, M. Tajbakhsh, M. Mokhtary, J. Chem. Res. (2005) 481. M.M. Lakouraj, M. Mokhtary, Lett. Org. Chem. 4 (2007) 64. J. Buckingham, S.M. Donaghy, Dictionary of Organic Compounds, sixth ed., Chapman and Hall, London, 1982. F. Kaiser, L. Schwink, J. Velder, H.G. Schmalz, Tetrahedron 59 (2003) 3201. T. Ooi, K. Maruoka, H. Yamamoto, Org. Synth. Coll. 9 (1942) 356. B. Jones, J. Chem. Soc. (1941) 358. D.L. Fox, E.E. Turner, J. Chem. Soc. (1930) 1853.