Abstract
We present herein the synthesis and structural characterization of a novel, recyclable and microwave stable polymeric reagent prepared by anchoring bromoderivative of oxazolidone into the 3D matrix of divinylbenzene crosslinked polystyrene and its application for the bromination of alkenes, activated aromatic compounds and for the α-halogenation of ketones under microwave irradiation. The advantages of this protocol include a simple workup procedure, high product yield, shorter reaction time as well as solvent-free reaction pathway. Besides, this new resin was stable under standard laboratory conditions and can be kept for several months without any significant loss of activity.
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Introduction
Bromination is one of the most significant transformations in synthetic organic chemistry and can be achieved by elemental bromine and numerous other bromo compounds [1]. The conventional method of bromination of organic compounds using elemental bromine has the disadvantages of corrosive effect, toxicity, handling difficulty, poor regioselectivity, overbromination and problems in separation of products from the reaction mixture [2,3,4]. Furthermore, inhalation of bromine vapors causes breathing problems and failure in the respiratory system [5]. Owing to the risky nature of elemental bromine, alternate bromine carriers are developed such as zeolite/KBr/H2O2 [6], KBr/BTPPMS [7], KBr/BTPPPD [8], ZrBr4/diaziene [9], IQBC [10] and [BMPy]Br3 [11]. But, some of these methods include severe reaction conditions and costly reagents, so in the past few decades, a variety of polymer-bound bromine carriers are prepared for organic synthesis [4, 12,13,14,15,16,17].
Polymer supported reagents have become the subject of extensive and increasing importance in organic chemistry because of their selectivity [18,19,20], recyclability [21,22,23], ease of separation of the products [24], little toxicity [25], ease of handling [26] and stability. The nature of the polymeric backbone, solvation and swelling characteristics and overall topology of the macromolecular matrix plays a decisive role in the reactivity of the functional group attached to the polymeric backbone [27]. Takemoto et.al found that the intrinsic chemical reactivity of a supported species can be enhanced by the chemical and structural characteristics of the support [28].
But the efficacy and selectivity of polymer-supported reactions are low related to solution-phase on account of the poor diffusion of the reactants through the polymeric network [29]. This disadvantage which confines its synthetic usefulness can be overwhelmed by running polymer-supported reactions under microwave (MW) conditions. MW assisted organic reactions are fast and as a result, the product and reagent decomposition is avoided, separation of the product from the reaction mixture is simplified, and yields are higher [30]. The use of dry media facilitates organic reactions to happen expeditiously at ambient pressure is another added advantage of MW assisted reactions [31,32,33,34].
Organic synthesis based on MW assisted and polymer-supported reagents have arisen independently as a competent strategy for efficient organic synthesis. The ability of a material to absorb microwave energy depends on its dielectric constant (ε’) whereas the dielectric loss factor (ε”) characterizes its capacity to convert the MW energy into heat. A high dissipation factor (tanδ = ε”/ ε’) is responsible for a high susceptibility to MW energy [35]. Polyethylene, polytetrafluoroethylene and polystyrene are best in the aspect of dielectric properties [36, 37]. However, the mechanical properties of polyethylene and polytetrafluoroethylene are very poor whereas polystyrene has improved rigidity. Polystyrene (PS) crosslinked with divinylbenzene (DVB) is one of the most promising MW transparent polymer [38].
Within this background, we wish to disclose the synthesis and characterization of a new polymeric reagent, divinylbenzene crosslinked polystyrene supported bromo derivative of 2-oxazolidone (DVB-PS-OX-Br) and its efficacy towards bromination reactions under MW irradiation. MW stability and recyclability of the newly synthesized polymeric reagent were also investigated.
Experimental
Materials and methods
The chemicals divinylbenzene (C10H10: 130.19 g/mol), styrene (C8H8: 104.15 g/mol) and 2-oxazolidone (C3H5NO2: 87.07 g/mol) were purchased from Sigma Aldrich Germany. The monomer styrene and the crosslinking agent divinylbenzene were washed with 1% NaOH solution (5 mL × 3) and with distilled water (5 mL × 3) to remove the inhibitor. 2-oxazolidone was used without any additional purification. All other reagents and solvents used were of analytical grade and used as such. Fourier transform infrared spectroscopy (FTIR) of the synthesized resins were recorded in the range 4000–450 cm−1 using Perkin Elmer FTIR spectrometer. The surface morphology of the synthesized resin was carried out by SEM JEOL (JSM6390lV) scanning electron microscope. Thermogravimetric analyses were carried out using a Perkin Elmer, Diamond TG/DTA instrument. An Elementar Vario EL III analyzer is used for CHN analysis. Thin-layer chromatography was performed on Silica Gel pre-coated plates (Merck). The products formed in various reactions were analyzed on a Thermo scientific Trace GC 1300 equipped with ISQLT single quadrupole mass spectrometer. Mass spectra were recorded in the EI mode. The proton NMR spectra were recorded on Bruker Advance 400 MHz instrument with TMS as an internal standard. A single-mode microwave synthesis reactor - Anton Paar monowave-300 is used for carrying out MW assisted chemical reactions.
Preparation of polystyrene supported 2-oxazolidone (DVB-PS-OX)
3% DVB crosslinked polystyrene (DVB-PS), its chloromethylated derivative (DVB-PS-Cl), and chloromethyl methyl ether (CMME) were prepared using the reported procedures [39,40,41]. For preparing DVB-PS-OX, 4 g chloromethylated resin (DVB-PS-Cl) was allowed to swell in dichloromethane (DCM) for 2 h and to the swollen bead, 4 g oxazolidone and 4 mL pyridine were added and refluxed for 24 h at 110 °C. The newly synthesized resin was filtered, washed with acetone and methanol several times. The resin was drained and dried at 80 °C. Yield – 5.5 g.
Preparation of bromo derivatives of polystyrene supported 2-oxazolidone (DVB-PS-OX-Br)
Bromo derivatives of DVB-PS-OX was prepared by the reported procedure [14]. DVB-PS-OX (5 g) in CCl4 (25 mL), bromine (5 mL) was added and stirred at 0 °C for 4 h at room temperature. The resultant dark orange colored resin on filtration and washing with CCl4 (5 mL × 5) yielded a stable non-hygroscopic product. The resin was dried in vacuum at 60 °C to give dark orange polymer (DVB-PS-OX-Br). Yield-7.5 g. The bromine capacity of the newly synthesized resin was determined by iodometric titration and was found to be 2.53 mmol/g [14].
Determination of the microwave stability of DVB-PS-OX-Br
The stability of DVB-PS-OX-Br resin towards MW irradiation was examined by heating the resin at two different temperatures (100 °C and 150 °C) in an Anton Parr Monowave300 MW synthesizer at an MW power level of 300 W for about 5 min. After 1,2,3,4 and 5 min, a certain amount of the resin was taken out, and its bromine efficiency was found out by iodometric titration [42].
Microwave-assisted bromination reactions using DVB-PS-OX-Br- general procedure
The low molecular weight organic substrate (0.5 g) was dissolved in DCM (1 mL) and a fivefold molar excess of DVB-PS-OX-Br (2.5 g) was added to this. The solvent was allowed to evaporate and the polymeric reagent with the adsorbed substrate was MW irradiated for 5 min at an MW power of 300 W. After every one minute of MW irradiation, the addition of DCM (0.5 mL) followed by evaporation of the solvent was repeated. The reactions were monitored by TLC. After 5 min of MW exposure, the insoluble spent reagent was filtered and washed with more solvent. The collective washings and filtrate were dried over anhydrous sodium sulphate and the conversion and selectivity were found out by GC-MS analysis. The above procedure was repeated with different organic substrates.
Regeneration of the spent reagent
The spent reagent obtained from different reactions were combined and washed with dichloromethane (2 mL× 5) to remove any trace of the organic substrate or product. Then the bromo group is introduced into the polymer by following the original method [14]. The renewed bromo resin was used for the halogenation of various organic substrates.
Results and discussion
Preparation of DVB-PS-OX-Br
2-oxazolidone was grafted onto DVB-PS-Cl by heating under reflux in the presence of pyridine for 24 h at 110 °C. DVB-PS-OX-Br resin was synthesized by stirring a suspension of the resin DVB-PS-OX in CCl4 with bromine on a magnetic stirrer for 4 h at room temperature. According to Koshy et al. in polyvinylpyrrolidone-bromine complex, the bromine functionality exists in the form of a tribromide complex [14]. They proposed that the absorbed water may facilitate the formation of bromide ion which can also complex with Br2 to form tribromide complex. D.H. Lorenz established the structure of the PVP-iodine complex as a triiodide complex based on X-ray analysis and infrared spectroscopic investigation [43]. Based on these we suggest a tribromide structure for our complex (Scheme 1).
FTIR studies
DVB-PS-Cl and DVB-PS-OX were characterized by FTIR spectroscopy. The FTIR spectra of DVB-PS-Cl (Fig.1a) shows a characteristic band for C-Cl stretching at 691 cm−1. The peak at 835 cm−1 is typical of the benzene ring of DVB. Another band at 2924 cm−1 indicates the presence of the –CH2 group. This is by the data reported by Jincy et.al [44]. The spectrum also shows a band at 3082 cm−1 corresponds to aromatic hydrogen. The grafting of DVB-PS-Cl with 2-oxazolidone has been confirmed by the appearance of a new peak at 1642 cm−1 in the IR spectrum of DVB-PS-OX (Fig.1b). This stretching band is attributed to the C=O group of the oxazolidone unit [45, 46]. The spectrum also exhibits bands at 1505 cm−1 and 1150 cm−1. These bands originate from the C-N stretching and ether group of the oxazolidone ring.
CHN analysis
The grafting of 2-oxazolidone to DVB-PS-Cl was again confirmed by CHN analysis. The CHN content of DVB-PS-Cl and DVB-PS-OX are given in Table.1.
Thermogravimetric analysis
The thermal stability of DVB-PS-Cl and DVB-PS-OX was investigated by thermogravimetric analysis. The Thermogram of DVB-PS-Cl (Fig.2, a) shows that it is stable up to 275 °C and undergoes degradation in two steps. Elimination of the chloromethyl group takes place in the first step at 275 °C and in the second step the degradation of the polymer chain starts from about 460 °C. The results are in good agreement with thermal studies reported by Zhao et al. [47]. Thermogram of DVB-PS-OX shows an initial mass loss of 10% due to the removal of absorbed water. The second mass loss of about 21% starting around 190 °C can be attributed to the loss of oxazolidone ring. (Fig.2, b). After that, the polymer chain follows the same degradation pattern as that of the chloromethylated resin.
SEM analysis
Figure 3(a,b) shows the SEM images of DVB-PS-OX at various magnification. The SEM micrographs show that the particles are spherical and almost uniform in size. The average particle size measured from the SEM image is observed to be 51.82 μm. The particle size distribution was shown in the histogram (Fig. 3,c).
Determination of the microwave stability of DVB-PS-OX-Br
The bromo resin DVB-PS-OX-Br should be stable to MW irradiation to perform synthetic reactions under MW conditions. To study the stability of DVB-PS-OX-Br polymer towards MW irradiation, 1 g of the bromo resin was MW irradiated at an MW power level of 300 W for about 5 min at two different temperatures (100 °C and 150 °C). After 1,2,3,4 and 5 min, a definite amount of the resin was taken out and its bromine capacity was estimated iodometric titration. The bromine capacity was found to be 2.48 mmol/g after 1 min of MW irradiation and there is only a decrease of 0.4 mmol/g in bromine efficiency after 5 min at 100 °C. When the temperature was elevated to 150 °C, the bromine capacity was found to be 1.93 mmol/g after 1 min of MW irradiation and there is a rapid fall in the bromine efficiency after 2 min. It may be because of the more vigorous release of bromine at high temperatures. Moreover, the resin gets charred after 3 min. Therefore we carried out all organic reactions at 100 °C for about 5 min at an MW power of 300 W.
Microwave-assisted halogenation reactions using DVB-PS-OX-Br
The novel method of synthesis of organic compounds always remains popular in synthetic organic chemistry [48, 49]. Our new resin, DVB-PS-OX-Br, is a safe and an environmentally stable reservoir of bromine. The resin is found to be effective for the bromination of olefinic and activated aromatic compounds and also for α-bromination of ketones under MW irradiation. The slow release of bromine from the reagent improves the safety of the experiments. The solvent-free condition further adds on to green chemistry protocols.
The various organic substrates undergo bromination by the reagent, time taken; products, conditions, conversion and selectivity are given in Table 2. As shown in Table 2, several olefinic compounds (entries 1–4) undergo bromination when MW irradiated with DVB-PS-OX-Br. Decarboxylative bromination leading to the formation of β-bromostyrene was observed for cinnamic acid. For cinnamaldehyde, instead of addition across the double bond, the substitution of bromine took place at the double bond. Styrene and cyclohexene are very efficiently converted to styrene dibromide and dibromocyclohexane on reaction with DVB-PS-OX-Br. We could achieve 100% conversion and selectivity for cinnamic acid, styrene and cyclohexene. Activated aromatic compounds were also treated with DVB-PS-OX-Br (Table 2 entries 6–7). Methyl substituted phenol smoothly reacted with reagent and gave the corresponding mono brominated product (selectivity-95%) whereas the bulky substituted phenol afford its dibrominated product (selectivity-80%) and mono brominated product (selectivity-16%). We have also studied the bromination of activated aniline such as N,N-dimethyl aniline (Table 2, entry-5) and obtained parabrominated product in moderate yield (conversion-40%, selectivity- 100%). In the α-bromination of acetanilide a low yield of the corresponding α-brominated isomer was formed (Table 2, entry-8).
One of the significant features of this polymeric reagent is the probability of recycling. The spent PS-DVB-OX-Br complex obtained after bromination reactions can be recycled back to the original reagent by washing with dichloromethane followed by treatment with Br2 in CCl4 (Scheme.2). In the current study, the reagent has been reused up to five times very competently. The bromine capacity of the regenerated resin was found to be almost the same even after five cycles of regeneration and reuse. The bromine capacity of the resin in different cycles is shown in the histogram (Fig.4).
Conclusion
We have prepared and characterized an innovative, powerful, recyclable and microwave stable polymeric reagent, divinylbenzene crosslinked polystyrene supported bromoderivatives of 2-oxazolidone and studied its behavior to act as an efficient halogenating agent under microwave irradiation. The major benefits of this method are shorter reaction time and a simple workup procedure. Moreover, the reagent has the advantage of improved shelf-life and recyclability. The use of microwave heating considerably decreases the reaction time and reduces environmental pollution through the usage of solvent-free reaction protocols. Besides, this new resin was stable under standard laboratory condition and can be kept for an extended time without any significant loss of activity.
Data availability
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References
Saikia I, Borah AJ, Phukan P (2016) Use of bromine and Bromo-organic compounds in organic synthesis. Chem Rev 116(12):6837–7042. https://doi.org/10.1021/acs.chemrev.5b00400
Smith K (1995) Advances in Organobromine chemistry II. Elsevier, New York, pp 4–64
Vanotterlo W (2004) Unforeseen formation of 2-bromo-3-hydroxybenzaldehyde by bromination of 3-hydroxybenzaldehyde. Tetrahedron Lett 45:5091–5094. https://doi.org/10.1016/s0040-4039(04)01010-x
El-Hamshary H, Selim AI, Salahuddin NA, Mandour HS (2015) Clay-polymer Nanocomposite-supported brominating agent. Clay Clay Miner 63(4):328–336. https://doi.org/10.1346/ccmn.2015.0630406
Rogers JV, Price JA, Wendling MQS, Perry MR, Reid FM, Kiser RC, Graham JS (2011) An assessment of transcriptional changes in porcine skin exposed to bromine vapor. J Biochem Mol Toxicol 25(4):252–262. https://doi.org/10.1002/jbt.20383
Narender N, Krishna Mohan KV, Reddy RV, Srinivasu P, Kulkarni S, Raghavan K (2003) Liquid phase bromination of phenols using potassium bromide and hydrogen peroxide over zeolites. J Mol Catal A Chem 192(1–2):73–77. https://doi.org/10.1016/s1381-1169(02)00131-0
Tajik H, Mohammadpoor-Baltork I, Albadi J (2007) Bromination of some aromatic compounds with potassium bromide in the presence of Benzyltriphenylphosphonium Peroxodisulfate. Synth Commun 37(2):323–328. https://doi.org/10.1080/00397910601033906
Adibi H, Hajipour AR, Hashemi M (2007) A convenient and regioselective oxidative bromination of electron-rich aromatic rings using potassium bromide and benzyltriphenylphosphonium peroxymonosulfate under nearly neutral reaction conditions. Tetrahedron Lett 48(7):1255–1259. https://doi.org/10.1016/j.tetlet.2006.12.033
Stropnik T, Bombek S, Kočevar M, Polanc S (2008) Regioselective bromination of activated aromatic substrates with a ZrBr4/diazene mixture. Tetrahedron Lett 49(11):1729–1733. https://doi.org/10.1016/j.tetlet.2008.01.07
Khansole SV, Patwari SB, Vibhute AY, Vibhute B (2009) Isoquinolinium bromochromate: an efficient and stable reagent for bromination of hydroxylated aromatic compounds and oxidation of alcohols. Chin Chem Lett 20(3):256–260. https://doi.org/10.1016/j.cclet.2008.11.015
Borikar SP, Daniel T, Paul V (2009) An efficient, rapid, and regioselective bromination of anilines and phenols with 1-butyl-3-methylpyridinium tribromide as a new reagent/solvent under mild conditions. Tetrahedron Letters 50(9):1007–1009. https://doi.org/10.1016/j.tetlet.2008.12.053
Zupan M, Segatin N (1994) Bromination of organic molecules with polymer-supported bromine complexes. Synthetic Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry 24(18):2617–2626. https://doi.org/10.1080/00397919408010574
Lakouraj MM, Tajbakhsh M, Mokhtary M (2005) Poly(vinylpyrrolidone)-bromide complex; a mild and efficient reagent for selective Bromination of alkenes and oxidation of alcohols. J Chem Res 8:481–483. https://doi.org/10.3184/030823405774663246
Koshy EP, Zacharias J, Rajasekharan Pillai VN (2006) Poly (N-vinylpyrrolidone)-hydrotribromide: a new gel type resin for alcohol oxidation ad alkene dibromination. Reactive & Functional Polymers 66(8):845–850. https://doi.org/10.1016/j.reactfunctpolym.2005.11.0
Mokhtary M, Lakouraj MM (2011) Polyvinylpolypyrrolidone–bromine complex: mild and efficient polymeric reagent for bromination of activated aromatic compounds. Chin Chem Lett 22(1):13–17. https://doi.org/10.1016/j.cclet.2010.06.002
Mokhtary M, Lakouraj MM (2012) Polyvinylpyrrolidone-bromine complex: an efficient polymeric reagent for selective preparation of benzyl bromides in the presence of hexamethyldisilane. Bull Chem Soc Ethiop 26(2):305–309. https://doi.org/10.4314/bcse.v26i2.14
Mokhtary M (2018) Recent advances in synthetic applications of polyvinyl pyrrolidone supported reagents and catalysts. Academic Journal of Polymer Science 2(1):555580. https://doi.org/10.19080/AJOP.2018.02.555580
Hodge P (1997) Polymer-supported organic reactions: what takes place in the beads? Chem Soc Rev 26:417–424. https://doi.org/10.1039/CS9972600417
Trost BM, Warner RW (1982) Macrocyclization via an isomerization reaction at high concentrations promoted by palladium templates. J Am Chem Soc 104(22):6112–6114. https://doi.org/10.1021/ja00386a045
Trost BM, Keinan E (1978) Steric steering with supported palladium catalysts. J Am Chem Soc 100(24):7779–7781. https://doi.org/10.1021/ja00492a084
Shuttleworth SJ, Allin SM, Wilson RD, Nasturica D (2000) Functionalised polymers in organic chemistry; part 2. Synthesis 8:1035–1074. https://doi.org/10.1055/s-2000-6310
McNamara CA, Dixon MJ, Bradley M (2002) Recoverable catalysts and reagents using recyclable polystyrene-based supports. Chem Rev 102:3275–3300. https://doi.org/10.1021/cr0103571
Hajjami M, Ghorbani-Choghamarani A, Norouzi M (2012) An efficient and facile procedure for synthesis of acetates from alcohols catalyzed by poly(4-vinylpyridinium tribromide). Chin J Catal 33(9–10):1661–1664. https://doi.org/10.1016/s1872-2067(11)60441-5
Ghorbani-Choghamarani A, Azadi G (2011) Polyvinylpolypyrrolidone-supported hydrogen peroxide (PVP-H2O2), silica sulfuric acid and catalytic amounts of ammonium bromide as green, mild and metal-free oxidizing media for the efficient oxidation of alcohols and sulphides. J Iran Chem Soc 8(4):1082–1090. https://doi.org/10.1007/bf03246566
Ghorbani-choghamarani A, Pourbahar N (2012) Polyvinylpolypyrrolidoniume Tribromide as an efficient catalyst for the acetylation of alcohols and phenols. Chin J Catal 33(9–10):1470–1473. https://doi.org/10.1016/s1872-2067(11)60428-2
Veerakumar P, Lu ZZ, Velayudham M, Lu KL, Rajagopal S (2010) Alumina supported nanoruthenium as efficient heterogeneous catalyst for the selective H2O2 oxidation ofaliphatic and aromatic sulfides to sulfoxides. Journal of Molecular catalysis A: Chemical 332:128–137. https://doi.org/10.1016/j.molcata.2010.09.008
Akelah A (1988) The use of functionalised polymers as polymeric reagents in solid phase organic synthesis- a review. Reactive Polvmers, Ion Exchangers, Sorbents 8(3):273–284. https://doi.org/10.1016/0167-6989(88)90303-0
Takemoto K, Inaki Y, Ottenbrite RM (1987) Functional monomers and polymers Dekker, N Y: 1–100
Thomas JM (1999) Design, synthesis, and in situ characterization of new solid catalysts. Angew Chem Int Ed 38(24):3588–3628. https://doi.org/10.1002/(sici)1521-3773(19991216)38:24<3588::aid-anie3588>3.0.co;2-4
De la Hoz A, Loupy A (2013) Microwaves in organic synthesis3rd edn. Wiley, Weinheim, Germany
Jaśkowska J, Drabczyk A, Kułaga D, Zaręba P, Majka Z (2018) Solvent-free microwave-assisted synthesis of aripiprazole. Current Chemistry Letters 7(3):81–86. https://doi.org/10.5267/j.ccl.2018.08.002
Ramírez JR, Caballero R, Guerra J, Ruiz-Carretero A, Sánchez-Migallón A, de la Hoz A (2015) Solvent-free microwave-assisted synthesis of 2, 5-Dimethoxyphenylaminotriazines. ACS Sustain Chem Eng 3(12):3405–3411. https://doi.org/10.1021/acssuschemeng.5b0113
Kamil F, Abid Hubeatir K, Shamel M, Al-Amiery AA (2015) Microwave-assisted solvent-free synthesis of new polyimine. Cogent Chemistry 1(1). https://doi.org/10.1080/23312009.2015.1075853
Patel JP, Avalani JR, Raval DK (2013) Polymer supported sulphanilic acid: a highly efficient and recyclable green heterogeneous catalyst for the construction of 4,5-dihydropyrano[3,2-c]chromenes under solvent-free conditions. J Chem Sci 125(3):531–536. https://doi.org/10.1007/s12039-013-0408-8
De la Hoz A, Díaz-Ortis A, Moreno A, Langa F (2000) Cycloadditions under microwave irradiation conditions: methods and applications. Eur J Org Chem 2000(22):3659–3673. https://doi.org/10.1002/1099-0690(200011)2000:22<3659::aid-ejoc3659>3.0.co;2-0
Subodh G, Deepu V, Mohanan P, Sebastian MT (2009) Polystyrene/Sr2Ce2Ti5O15composites with low dielectric loss for microwave substrate applications. Polym Eng Sci 49(6):1218–1224. https://doi.org/10.1002/pen.21220
O’Keefe S, Luscombe CK (2016) Microwave dielectric properties of polytetrafluoroethylene-polyacrylate composite films made via aerosol deposition. Polym Int 65(7):820–826. https://doi.org/10.1002/pi.5138
Chen Y, Mao J, Zhu Y, Zhang K, Wu G, Wu J, Zhang H (2017) Structure and properties of microwave transparent crosslinked polystyrene prepared through 3D printing bulk polymerization. J Appl Polym Sci 134(30):44865. https://doi.org/10.1002/app.44865
Sherrington DC, Hodge P (1980) Polymer supported reactions in organic synthesis, J. Wiley & Sons, New York
Arunan C, Pillai VNR (2003) 1,6-hexanediol diacrylate-crosslinked polystyrene: preparation, characterization, and application in peptide synthesis. Journal of Applied Polymer Science 87(8):1290–1296. https://doi.org/10.1002/app.11538
Marvel CS, Porter PK (1941) Organic synthesis collection, Vol.I, 2nd edition, Wiley, New York,
Sebastian SM (2013) Microwave assisted reactions using polyvinylpyrrolidone supported reagents. Mahatma Gandhi University, Kottayam, Kerala, India, Dissertation
Lorenz DH (1971) N-Vinylamide polymers. Encyclopedia of Polymer Science and Technology 14:239–251
Jose J, John M, Mathew B (2003) Effect of the nature of crosslinking agent on the catalase-like activity of polystyrene-bound glycine–metal complexes. Journal of Macromolecular Science, Part A: Pure and Applied Chemistry 40(8):863–879. https://doi.org/10.1081/MA-120022276
Suhas DP, Jeong HM, Aminabhavi TM, Raghu AV (2013) Preparation and characterization of novel polyurethanes containing 4,4′-{oxy-1,4-diphenyl bis(nitromethylidine)}diphenol schiff base diol. Polym Eng Sci 54(1):24–32. https://doi.org/10.1002/pen.23532
Raghu AV, Anita G, Barigaddi YM, Gadaginamath GS, Aminabhavi TM (2007) Synthesis and characterization of novel polyurethanes based on 2,6-bis(4-hydroxybenzylidene) cyclohexanone hard segments. J Appl Polym Sci 104(1):81–88. https://doi.org/10.1002/app.25518
Zhao HC, Guo JL, Li JT, Gao LL, Bian CC (2010) Synthesis and thermal property of linear Chloromethylated polystyrene. Adv Mater Res 150-151:1504–1507. https://doi.org/10.4028/www.scientific.net/amr
Donawade DS, Raghu AV, Gadaginamath GS (2007) Synthesis and antimicrobial activity of novel linearly fused 5-Substituted-7-acetyl-2,6-dimethyloxazolo[4,5-f]indoles. ChemInform 38(31). https://doi.org/10.1002/chin.200731099
Donawade DS, Raghu AV, Gadaginamath GS (2006) Synthesis and antimicrobial activity of some new 1-Substituted-3-pyrrolyl Aminocarbonyl/Oxadiazolyl/Triazolyl/5-Methoxy-2-methylindoles and Benz[g]indoles. ChemInform 37(28) http://hdl.handle.net/123456789/6383
Acknowledgements
The financial assistance to Anjaly Mathew from University Grants Commission, Government of India under minor research project, is gratefully acknowledged. The authors would like to thank SAIF STIC, CUSAT, Kerala, India for characterization facilities.
Funding
This work was supported by the University Grants Commission Government of India, under the Minor Research Project. [No. 2265-MRP /15–16/KLCA029/UGC-SWRO dated 25th April 2016].
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Highlights
• Divinylbenzene crosslinked polysterene supported bromoderivative of 2 –oxazolidone (DVB-PS-OX-Br) is an efficient, recyclable, microwave-safe and an environmentally stable reservoir of bromine
• DVB-PS-OX-Br is used for the bromination of alkenes, activated aromatic compounds and for the α-bromination of ketones under microwave irradiation
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Figure S1 GC-MS spectra of bromostyrene Fig.S2 GC-MS spectra of α-Bromo cinnamaldehyde Fig.S3 GC-MS spectra of Styrene dibromide Fig.S4 GC-MS spectra of Dibromo cyclohexane Fig.S5 GC-MS spectra of 4-Bromo-N,N-dimethylaniline Fig.S6 GC-MS spectra of 4-Bromo-2,6-Dimethyl phenol Fig.S7 GC-MS spectra of 2,6-Dibromo-4-tert-butyl phenol Fig.S8 GC-MS spectra of α-Bromoacetanilide Fig. S9 1H NMR spectrum of β-Bromostyrene Fig. S10 1H NMR spectrum of Styrenedibromide (DOCX 733 kb)
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Mathew, A., Mathew, B. & Koshy, E.P. Polystyrene supported bromoderivative of 2-oxazolidone – an efficient reagent for microwave assisted bromination reactions. J Polym Res 27, 271 (2020). https://doi.org/10.1007/s10965-020-02251-w
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DOI: https://doi.org/10.1007/s10965-020-02251-w