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1 Electronic Supplementary Material (ESI) for RSC Advances. This journal is The Royal Society of Chemistry Supporting Information ano Fe 3 O supported Biimidazole Cu(I) Complex as a retrievable catalyst for the synthesis of imidazo[,-a]pyridines in aqueous medium Mahmood Tajbakhsh,* Maryam Farhang, Rahman Hosseinzadeh, Yaghoub Sarrafi Faculty of Chemistry, Mazandaran University, Babolsar,, Iran Fax: (+)0, Tajbaksh@umz.ac.ir Tajbaksh@iauamol.ac.ir. General information S. Characterizations of Catalyst S-S 3. Synthesis of Catalyst S 3.. General details S 3.. Preparation of, -biimidazole(biim)i S 3.3. Preparation of 3-chloropropyl-functionalized magnetic nanoparticles (MP@CPS) S 3.. Preparation of MP@BiimCu catalyst S. General procedure for synthesis of imidazo[,-a]pyridine derivatives S. Spectral data for selected compounds S- Copies of H and C MR for selected imidazo[,-a]pyridines products S S

2 . General Information: The catalyst was characterized by various techniques such as elemental analyzed (CH), MR, FT-IR, TG, SEM, TEM, EDS, XRD, AAS, ICP- OES and vibrating sample magnetometer (VSM) which revealed the superparamagnetic nature of the particles. All chemicals were purchased and used without any further purification. MR spectra were recorded at 00 MHz for proton and at 0 MHz for carbon nuclei in (CDCl 3 ).. Characterizations of Catalyst: The FT-IR spectra of MPs (a), MP@SiO (b), MP@CPS (c), Bim (d) and MP@BiimCu (e) were shown in Fig.. Fig. FTIR spectra of MPs (a), MP@SiO (b), MP@CPS (c), Bim (d), MP@BiimCu (e). XRD pattern: The X-ray diffraction analysis was done in a Philips PW 30 X-ray diffractometer with CuKα source. S

3 Fig.. XRD patterns of MPs (a) and (b) Thermo gravimetric analysis (TG) results indicate the loading amount of functionalized organic groups on magnetic were. mmol/g. Fig. 3.The TGA thermogram of (a) (b) C/min under atmosphere The morphology of the powders was investigated by scanning electron microscopy (SEM). SEM analysis (Fig. ) of the ano-magnetic catalyst showed uniform-sized particles with spherical morphology with an average size range of nm. Fig. displays HRTEM image of MP@BiimCu nanoparticles. As may be seen in the TEM image, the size of particles is around nm and the particles are spherical in shape with some agglomeration, which is obvious because of the magnetic nature of the particles. S3

4 Fig.. SEM images of synthesized (left) used (right) Fig.. Transmis sion elect ron microscopy (TEM) image of Elemental analysis for and were carried out and the data were tabulated in Table which is shown to be in good agreement with the result obtained from TGA (Fig. 3). Further to support the above observation, the EDX analysis of magnetic nanocatalyst indicates that CuI was chelated on the surface of nanoparticles (Fig. ). Table. Elemental analysis for and Samples C% H% % Cu% MP@SiO MP@ CPS MP@BiimCu....3 a,. b,. b. c a, b The amount of copper was determined using a AAS and b ICP, c Recycled after ten times S

5 Fig.. EDS pattern of Cu The magnetic hysteresis measurements of both and nanocrystallites obtained by VSM at 300 K, with the field sweeping from 000 to +000 Oe. As shown in Fig. the relatively high saturation magnetization of synthesized nanoparticles is sufficient for magnetic separation with a conventional magnet (Fig. c). Fig.. VSM curve of MP@SiO (a) vs. MP@BiimCu (b), (c) MP@BiimCu ability to effective recovery at the end of reaction S

6 3. Synthesis of Catalyst: 3. General details Chemical materials were purchased from Merck and Aldrich Chemical Company in high purity. All the solvents were distilled, dried and purified by standard procedures. Melting points were measured on an Electrothermal 0 apparatus. The samples were analyzed using FT-IR spectroscopy (Bruker Vector Perkin Elmer in KBr matrix). The X-ray powder diffraction (XRD) of the catalyst was carried out on a Philips PW 30 X-ray diffractometer with CuKα source (λ=. Å) in a range of Bragg s angle (-0 ) at room temperature. Scanning electron microscope (SEM) pictures-eds analyses were taken using VEGA//TESCA KYKY-EM30 microscope (acceleration voltage kv). Transmission electron microscopy (TEM) experiments were conducted on a Philips EM electron microscope. The samples for TEM measurements were suspended in ethanol by sonication and then drop drying on a copper grid (00 mesh) coated with carbon film. H, C MR spectra were recorded on a BRUKER DRX-00 AVACE spectrometer. Elemental analyses for C, H and were performed using a Heraeus CH-O-Rapid analyzer. Mass spectra were recorded on a FIIGA-MATT 30 mass spectrometer operating at an ionization potential of ev.magnetic measurements were performed using vibration sample magnetometry (VSM, (MDK Co. Kashan, Iran) analysis. A simultaneous ICP-OES (Varian Vista-Pro, Springvale, Australia) coupled to a V-groove nebulizer and equipped with a charge cou-pled device (CCD) was applied for determination of the trace. 3.. Preparation of, -biimidazole(biim)i To a mixture of ammonium acetate (0. mol, 3. g) and H O (. ml) was added dropwise glyoxal (0.3 mol,.0 g) solution (%) at 0 C over a period of 3 h then the mixture was allowed to stir for an additional h at room temperature. The reaction mixture was filtered and then washed with distilled water (3 ml) and acetone (3 ml) to give a crude product. The brown solid was dissolved in 0 ml of hot ethylene glycol, and decolorized with activated carbon. After hot filtration, the product precipitated instantly to provide 3. g (%) of white crystalline I[] Preparation of 3-chloropropyl-functionalized magnetic nanoparticles (MP@CPS) A mixture of FeCl 3 H O (.3 g,. mmol) and FeCl H O (0. g,.3 mmol) were dissolved in 0 ml deionized water. The resultant solution was left to be stirred for 30 min at 0 ºC. Then ml of H OH solution was added with vigorous stirring to produce a black solid and the reaction was continued for another 30 min. The black magnetite nanoparticles were isolated by magnetic decantation, washed several times with deionized water and then dried at 0 ºC for h. 0. g of dried Fe 3 O nanoparticles were suspended in a mixture of 0 ml ethanol and ml of H 3 H O. Then, 0. ml of tetraethoxysilane (TEOS) was added to solution and the mixture was ultrasonicated for h. Afterward silica coated MP (MP@SiO ) was magnetically separated, washed three times with ethanol and dried at 0 ºC for h. S

7 (0mg) was dispersed in ml of dry toluene by ultrasonication under nitrogen atmosphere. ext, 3-chloropropyltriethoxysilane (0. ml, 0.mml) was dropwise added into the solution under reflux condition for h[].the CPS functionalized magnetic nanoparticles was washed with 30 ml of toluene and ethanol before being dried at 0 ºC for h. 3.. Preparation of MP@BiimCu catalyst Sodium hydride. g (0.0 mol) was suspended in ml of dry DMF under inert atmosphere. To this suspension,. g of Biimidazole (0.0 mol) was added and stirred for 30 more minutes at room temperature. The MP@CPS (. gr) was then added to this suspension and mixture was stirred at ºC for days. The dark brown precipitate formed was filtered, washed with water and methanol and then soxhlet extraction by hot methanol to remove no reacted specie and dried under vacuum at 0 ºC. A mixture of MP@Biim ( g), copper iodide (00 mg) and dry acetonitrile (30 ml) was stirred at room temperature under nitrogen atmosphere for h. The resulting solid was then separated by an external magnet and washed with acetonitrile and acetone for several times. The residue was dried for h in air to afford the ano Fe 3 O supported Biimidazole Cu(I) Complex (MP@BiimCu). Preparation of MP@BiimCu a) 0 ml EtOH (0mL), H 3 H O ( ml), TEOS (0. ml) for h; b) dry toluene ( ml), CPTES (0. ml), reflux for h; c) Bim (. g), ah (.g) in DMF ( ml) in ºC for h, d) CuI (0.g) and dry CH 3 C (30 ml) under for h S

8 . General procedure for the synthesis of imidazo[,-a]pyridine derivatives In a ml round bottomed flask, a mixture of -aminopyridine ( mmol) and benzaldehyde ( mmol) was stirred. After min, phenylacetylene (. mmol), MP@Bim Cu (0.0 g,. mol %), 0.00g CTAB and ml H O were added to the above mixture and the resulting mixture was allowed to stir under reflux conditions for specified period of time. The progress of the reaction was monitored by thin-layer chromatography (TLC). After completion of the reaction the catalyst was magnetically separated. The residue was extracted with EtOAc ( ml) followed by drying with anhydrous a SO. After evaporation of the solvent, the residue was purified by flash chromatography to afford the desired product. Cl 3-Benzyl--(-chlorophenyl)imidazo[,-a]pyridine (Table,Entry ),3,, and. White solid, mp C. H MR (00 MHz, CDCl 3 ) δ =..3 (m, H),.3-.3 (m, H),.. (m, 3H),.. (m, H),. (d, J =. Hz, H),.3 (dt, J =.0 Hz, J =. Hz, H),. (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =.(C),.(C),.(C),.(C),0.(C and ),.(C),.(C and ),.0(C and ),.(C),.(C),.(C and ), 3.(C),.(C),.(C),.(C),.(C). HRMS (ESI) [M+H] calcd for C H Cl : 3.0, found: Benzyl--phenylimidazo[,-a]pyridine (Table, Entry).,3,, and White crystalline solid, mp - C. S

9 H MR (00 MHz, CDCl 3 ) δ =.0. (m, H),.0. (m, H),.3 (td, J =.0 Hz, J =. Hz, H),.-.3 (m, H),..3 (m, H),. (d, J =. Hz, H),. (dt, J =. Hz, J =. Hz, H),.3 (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =.(C),.(C),.(C),.(C),.0(C, ),.(C, ),.(C,),.(C, ),.3(C).(C),.(C), 3.(C),.(C),.3(C),.(C),.(C). HRMS (ESI) [M+H] calcd for C H :., found:.0. o 3-Benzyl--(-methoxyphenyl)imidazo[,-a]pyridine (Table, Entry3)., White crystalline solid; mp 0- C. H MR (CDCl 3, 00MHz) δ =.3 (m, H),.3. (m, H),. (m, H),.0 (d, J =. Hz, H),. (m, H),.0 (s, H, CH ), 3. (s, 3H, OCH 3 ). C MR (0 MHz, CDCl 3 ) δ =.3(C),.(C),.(C),.(C),.(C, ),.3(C,),.(C, ),.(C),.(C),.(C), 3.(C),.(C),.(C),.(C),.(C, ),.(C), 30.(C). HRMS (ESI) [M+H] calcd for C H O: 3., found: 3.3. Br 3-Benzyl--(-bromophenyl)imidazo[,-a]pyridine (Table, Entry)., and Yellow crystals: decomposes at 0 -C. H MR (00 MHz, CDCl 3 ) δ =.3. (m, H),.3 (d, J =. Hz, H),. (d, J =. Hz, H),.33. (m, 3H),. (t, J =. Hz, H),. (d, J =. Hz, H),. (t, J =. Hz, H),.3 (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =.(C), 3.(C),.(C), 3.(C,),.(C, ), 0.(C),.3(C, ),.(C),.3(C),.(C, ), 3.(C),.(C),.(C),.(C),.3(C),.(C). S

10 HRMS (ESI) [M+H] calcd for C H Br : 33.3, found: Benzyl--p-tolylimidazo[,-a]pyridine (Table,Entry )., and Light yellow solid; mp 0 C. H MR (00 MHz, CDCl 3 ) δ =. (m, H),.3-.3 (m, H),.-. (m, H),. -. (m, 3H),. (t, J =. Hz, H),. (s, H, CH ),. (s, 3H, CH 3 ). C MR (0 MHz, CDCl3) δ =.(C),.(C),.(C),.(C),.(C, ),.(C),.(C, ),.3(C, ),.(C, ),.(C),.(C), 3.(C),.(C),.(C),.0(C),.(C),.3. (C3). HRMS (ESI) [M+H] calcd for C H :.3, found:.. 3 -(3-Benzylimidazo[,-a]pyridin--yl)benzonitrile (Table,Entry )., and Light yellow solid; mp C. H MR (00 MHz, CDCl 3 ) δ =. (d, J =. Hz, H),. (d, J =. Hz, H),.0. (m, 3H),.3. (m, 3H),.. (m, H),. (d, J=. Hz, H),. (m, H),. (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =.(C),.(C),.(C),.3(C, ),.(C),.(C, ),.(C, ),.(C, ),.(C),.0(C), 3.(C),.(C),.(C3),.(C),.(C),.(C),.(C). HRMS (ESI) [M+H] calcd for C H 3 : 30.3, found: CF3 3-Benzyl--(-(trifluoromethyl)phenyl)imidazo[,-a]pyridine (Table,Entry ). White solid; mp - C. S

11 H MR (00 MHz, CDCl 3 ) δ =. (d, J =. Hz, H),.-. (m, H),. -.3 (m, 3H),. (t, J =.0 Hz, H),. (d, J =.0 Hz, H),. (t, J =. Hz, H),. (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =.(C), 3.(C),.(C),.(C),.(C3),.3(C, ),.(C),.(C, ),.(C, ),.(C),.(C),.(C, ),.(C),.(C),.(C),.(C),.(C). HRMS (ESI) [M+H] calcd for C H F 3 : 3., found: 3.. F 3-Benzyl--(-fluorophenyl)imidazo[,-a]pyridine (Table,Entry )., and Light yellow oil; mp C. H MR (00 MHz, CDCl 3 ) δ =.-. (m, H),..3 (m, 3H),.-.3 (m, H),.. (m, H),. (t, J =. Hz H),. (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =. (d, J C F =. Hz) (C),.(C), 3.3(C),.(C),.(C, ),. (d, J C C C F =.3 Hz) (C, ),.(C),.(C, ),.0(C), 3. (d, J C C F =. Hz) (C, ),.(C),.(C),.(C),.3(C),.(C). HRMS (ESI) [M+H] calcd for C H F : 30.3, found: Benzyl--(-methylphenyl)imidazo[,-a]pyridine (Table,Entry ). Semisolid. H MR (00 MHz, CDCl 3 ) δ =.. (m, H),.-.3 (m, H),..3 (m, H),. (d, J =. Hz, H),. (t, J =. Hz, H),. (s, H, CH ),. (s, 3H, CH 3 ). C MR (0 MHz, CDCl 3 ): δ =.(C),.(C),.(C),.3(C),.(C), 0.(C, ), 0.(C),.(C),.(C, ),.(C),.(C, ),.(C),.(C),.(C, ),.(C),.(C),.3(C3). HRMS (ESI) [M+H] calcd for C H :., found:.. S

12 Cl 3-Benzyl--(-chlorophenyl)imidazo[,-a]pyridine (Table,Entry )., Brown crystalline solid; mp ºC. H MR (00 MHz, CDCl 3 ) δ =.3. (m, H),.. (m, H).. (m, H),.3.30 (m, H). (d, J =.0 Hz, H),.. (m, H),.03 (d, J =.3 Hz, H),. (t, J =.0 Hz, H),.3 (s, H, CH ). CMR (CDCl3, MHz) δ =.3(C),.(C),.(C), 3.(C),.(C), 0.(C, ),.(C),.(C),.(C),.(C, ),.(C),.(C),.(C),.(C),.(C, ),.(C),.(C). HRMS (ESI) [M+H] calcd for C H Cl : 3.0, found: 3.0. Br 3-Benzyl--(3-bromophenyl)imidazo[,-a]pyridine (Table,Entry ). 3 White solid; mp = - C. H MR (00 MHz, CDCl 3 ) δ=.03 (t, J = Hz, H),.-. (m, 3H),.. (m, H),.30.3 (m, H),.. (m, H),. (d, J =.0 Hz, H),. (td, J =. Hz, J =.0 Hz, J =. Hz, H ),. (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ=.(c),.(c),.(c),.3(c),. (C, ),.(C),.(C),.(C, ),.(C),.3(C),.(C),.(C),.(C), 3.(C),.(C),.(C),.3(C),.(C). HRMS (ESI) [M+H] calcd for C H Br : 33.3, found: 33.3 Cl 3-Benzyl--(3-chlorophenyl)imidazo[,-a]pyridine (Table,Entry ).,, and S

13 White solid; mp = - C. H MR (00 MHz, CDCl 3 ):. (s, H),.-. (m, H),.-. (m, H),.-.3 (m, H),. -. (m, H),.0 (d, J =. Hz, H),. (dt, J =. Hz, J =. Hz, H),. (s, H, CH ). C MR (0 MHz, CDCl3):.(C),.(C),.(C),.(C, ),.(C),.(C),.(C),. (C),.(C, ),.3(C),.(C),.(C),.(C), 3.(C),.(C),.3(C),.(C),.(C). HRMS (ESI) [M+H] calcd for C H Cl : 3.03, found: Benzyl--(naphthalen--yl)-imidazo[,-a]pyridine (Table,Entry). 3 White solid; mp = - C. H MR (00 MHz, CDCl 3 ) δ=. (d, J =. Hz, H),. (d, J =. Hz, H),. (d, J =. Hz, H),.3. (m, H),.. (m, H),. (d, J =. Hz, H),. (t, J =. Hz, H),.3 (s, H, CH ). C MR (0 MHz, CDCl 3 ) δ =.3(C),.(C),.(C), 3.(C, ),.(C),.(C),.(C, 3),.(C),.(C),.(C),.3(C),.(C),.(C),.(C),.3(C),.(C), 3.(C),.(C),.(C),.(C),.(C). HRMS (ESI) [M+H] calcd for C H : 33., found: 33.. o 3 3-Benzyl--(furan--yl)imidazo[,-a]pyridine (Table,Entry)., Brown crystalline solid; mp= - C. H MR (CDCl 3, 00 MHz) δ =. (d, J =. Hz, H),. (d, J =. Hz, H),. (s, H),.. (m, H),.03 (d, J =. Hz, H),. (t, J =. Hz,H),.0. (m, H),,3 (s, H, CH ). S

14 C MR (CDCl 3, 0 MHz) δ =.3(C),.0(C),.(C),.(C),.3(C),.(C, ),.(C, ),.(C),.3(C),.(C),.(C),.(C),.(C),.(C),.(C3),.(C). HRMS (ESI) [M+H] calcd for C H O:., found:.. 3-Benzyl--(propyl)imidazo[,-a]pyridine (Table,Entry). Yellow oil; H MR (00 MHz, CDCl 3 ) δ =. (t, J=. Hz, H),..30 (m, H),.. (m, H),. (t, J=. Hz, H),. (s, H, CH ),.3 (t, J=. Hz, H, C H),.. (m, H, C H),. (t, J=. Hz, 3H, CH 3 ). C MR (0 MHz, CDCl 3 ) δ =.(C),.(C),.3(C), 3.(C, ), 3.(C, ),.3(C),.(C),.(C),.(C, ),.(C),.(C),.(C),.3(C),.(C). HRMS (ESI) [M+H] calcd for C H :., found:.. 3-Benzyl--(isopropyl)imidazo[,-a]pyridine (Table,Entry)., Yellow crystals; mp= -3 ºC. H MR (00 MHz, CDCl 3 ) δ =. (t, J =. Hz, H), (m, H),. (s, H),. (s, 3H),. (t, J =. Hz, H),.3 (s, H, CH ), (m, H, C H),. (d, J=.3 Hz, H, CH 3 ). C MR (0 MHz, CDCl 3 ) δ =.(C),.3(C),.(C),.(C, ),.(C), 3.(C, ), 3.(C),.(C),.(C, ),.(C),.(C),.(C),.(C, ). HRMS (ESI) [M+H] calcd for C H :., found:.. S

15 3 3 3-Benzyl-(-methyl--phenyl)imidazo[,-a]pyridine(Table, Entry )., White solid; mp= -º C. H MR(00 MHz, CDCl 3 ) δ =.. (m, H),. (d, J =.3 Hz, H),. (s, H),.. (m, H),..3 (m, H),. (d, J =. Hz, H),. (dd, J=.,. Hz, H),. (s, H, CH ),. (s, 3H, CH 3 ). C MR (0 MHz, CDCl 3 ) δ =.(C), 3.(C),.(C),.(C),.3(C, ),.(C),.(C, ),.(C),.(C),.3(C, ),.(C, ),.(C),.(C),.3(C),.(C),.(C),.(C3). HRMS (ESI) [M+H] calcd for C H :.3, found: Benzyl-(-methyl--phenyl)imidazo[,-a]pyridine (Table, Entry ). light yellow crystals; mp= - ºC. H MR (00 MHz, CDCl 3 ) δ =. (s, H),.3 (d, J =. Hz, H),.3 (s, H),. -.3 (m, H),. (d, J =. Hz, H),.03 (d, J =. Hz, H),. (t, J =. Hz, H),. (s, H, CH ),. (s, 3H, CH 3 ). C MR ( MHz, CDCl 3 ) δ =.3(C),.(C),.(C),.(C),.(C, ),.(C),.(C),.(C, ),.(C, ),.(C,),.(C),.(C),.(C),.(C),.(C),.(C),.(C3). HRMS (ESI) [M+H] calcd for C H :., found:.. Reference [] J-C. Xiao, B. Twamley, and J-M. Shreeve, Org. Lett. 0,, 3 3. [].Chernyak, and V. Gevorgyan, Angew. Chem., Int. Ed.,, 3. [3] B.V.S. Reddy, P.S. Reddy, Y.J. Reddy and J.S. Yadav, Tetrahedron Lett.,, 3. S

16 [] S.K. Guchhait, A.L. Chandgude and G. Priyadarshani, J. Org. Chem.,, 3. [] P. Liu, C-L. Deng, X. Lei, G.-q. Lin, Eur. J. Org. Chem., [] P. Liu, L.S. Fang, X. Lei and G.Q. Lin, Tetrahedron Lett.,, 0 0. [] T. Guntreddi, B.K. Allam and K.. Singh, Synlet,t, 3, 3 3. [] S. Mishra and R.Ghosh, Synthesis, S

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