• Omprakash G. Bhusnure Channabasweshwar Pharmacy College, Latur Kawa Road, Mahatambasweshwar Chowk, latur
  • Yaswant B. Vibhute Yeshwant Mahavidyalaya
  • Padmaja S Giram Channabasweshwar Pharmacy College (Degree), Latur (MS), India
  • Archana Y. Vibhute Yeshwant Mahavidyalaya
  • Sachin B. Gholve Yeshwant Mahavidyalaya


Schiff bases, Nil, Solvent-free, Microwave heating, Environmentally friendly


Objective: To optimize microwave assisted solvent free synthesis of Schiff bases of aromatic aldehydes and aromatic amines (ethyl 4-aminobenzoate) by using wetting reagent ð›½-ethoxyethanol. The goal of this study was to investigate the % yields and time required for the completion of reaction for Schiff bases by microwave and conventional conditions.

Methods: Schiff bases have been synthesized by condensation of substituted various aromatic aldehyde (.001 mol) with Ethyl 4-aminobenzoate (.001 mol) by two different methods as by conventional method (Heating) & Microwave accelerated synthesis by using wetting reagent ð›½-ethoxyethanol. The reaction time for conventional method and microwave method is in the range of 60-240 min and 10-180s respectively. All the synthesized compounds recrystallized & characterized by IR, NMR, and Mass and element analysis.

Results: The simple microwave assisted solvent-free method for the synthesis of Schiff bases using a wetting reagent (ð›½-ethoxyethanol) led to improvement in the yield of all the target compounds with reduction in their reaction byproducts & substantially reduced the overall process time as expected as compare to traditional method. Excellent isolated yields (up to 96%) were attained within short reaction times (typically, 60s) when the reaction was performed under microwaves irradiation.

Conclusion: The advantages of this environmentally benign and safe protocol include a simple reaction set-up, high product yields, short reaction times as well as the elimination of side products.



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Author Biography

Omprakash G. Bhusnure, Channabasweshwar Pharmacy College, Latur Kawa Road, Mahatambasweshwar Chowk, latur

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AM Asiri, SA Khan. Synthesis and anti-bacterial activities of some novel Schiff bases derived from aminophenazone. Molecules 2010;15(10):6850–8.

RW Layer. The chemistry of imines. Chem Rev 1963;63:489–510.

HK Fun, R Kia, AM Vijesh, AM Isloor. 5-Diethylamino-2-[(E)-(4-methyl-3-nitrophenyl) iminomethyl]phenol: a redetermination. Acta Crystallogr Sect E: Struct Rep Online 2009;65:349–50.

H Schiff. Surquelques derives pheniques des aldehydes. Annl Chim 2008;131:118.

KTaguchi, FH Westheimer. Catalysis by molecular sieves in the preparation of ketimines and enamines. J Org Chem 1971;36:1570–72.

ME Kuehne. The application of enamines to a new synthesis of ð›½-ketonitriles. J Am Chem Soc 1959;81(20):5400–4.

MA Vazquez, M Landa, L Reyes, R Miranda, J Tamariz, F Delgado. Infrared irradiation: effective promoter in the formation of N-benzylideneanilines in the absence of solvent. Synth Commun 2004;34(15):2705–18.

AK Chakraborti, S Bhagat, S Rudrawar. Magnesium perchlorate as an efficient catalyst for the synthesis of imines and phenylhydrazones. Tetrahedron Lett 2001;45(41):7641–4.

H Naeimi, H Sharghi, F Salimi, K Rabiei. Facile and efficient method for preparation of Schiff bases catalyzed by P2O5/SiO2 under free Solvent conditions. Heteroat Chem 2008;19(1):43–7.

JH Billman, KM Tai. Reduction of Schiff bases. II: benzhydrylamines and structurally related compounds. J Org Chem 1958;23(4):535–9.

M Gopalakrishnan, P Sureshkumar, V Kanagarajan, J Thanusu. New environmentally-friendly solvent-free synthesis of imines using calcium oxide under microwave irradiation. Res Chem Intermed 2007;33(6):541–8.

JS Bennett, KL Charles, MR Miner. Ethyl lactate as a tunable solvent for the synthesis of aryl aldimines. Green Chem 2009;11(2):166–8.

RS Varma, R Dahiya, S Kumar. Clay catalyzed synthesis of imines and enamines under solvent-free conditions using microwave irradiation. Tetrahedron Lett 1997;38(12):2039–42.

WA White, H Weingarten. A versatile new enamine synthesis. J Org Chem 1967;32(1):213-4.

F Texier-Boullet. A simple, convenient and mild synthesis of imines on alumina surface without solvent. Synthesis 1985;6(7):679–81.

L Ravishankar, SA Patwe, N Gosarani, A Roy. Cerium (III)-catalyzed synthesis of schiff bases: a green approach. Synth Commun 2010;40(21):3177–80.

KP Guzen, AS Guarezemini, R Cella, CMP Pereira, HA Stefani. Eco-friendly synthesis of imines by ultrasound irradiation. Tetrahedron Lett 2007;48(10):1845–8.

R Annunziata, M Benaglia, M Cinquini, F Cozzi. Poly(ethylene glycol)-supported 4-alkylthio-substituted aniline: a useful starting material for the soluble polymer-supported synthesis of imines and 1,2,3,4-tetrahydroquinolines. Eur J Org Chem 2002;7:1184–90.

M Hosseini-Sarvari. Nano-tube TiO2 as a new catalyst for eco-friendly synthesis of imines in sunlight. Chin Chem Lett 2011;22(5):547–50.

G Dutheuil, S Couve-Bonnaire, X Pannecoucke. Diastereomeric fluoroolefins as peptide bond mimics prepared by asymmetric reductive amination of ð›¼-fluoroenones. Angewandte Chemie: Int Edition 2007;46(8):1290–2.

JF Collados, E Toledano, D Guijarro, M Yus. Microwave-assisted solvent-free synthesis of enantiomerically pure N-(tert-Butylsulfinyl) imines. J Org Chem 2012;77:5744–50.

National Research Council (US). Subcommittee on Spacecraft Maximum Allowable Concentrations (1996). Spacecraft maximum allowable concentrations for selected airborne contaminants. National Academies Press; 2012. p. 189.

CO Kappe, D Dallinger, SS Murphree. Practical microwave synthesis for organic Chemists Strategies, instruments, and protocols. 1st Edition. Wiley-VCH, Verlag GMBH & Co Weinheim; 2009. p. 205-12.

M Larhed, A Hallberg. Microwave accelerated homogenous catalysis in organic chemistry. Acc Chem Res 2002;35:717-27.

JP Tierney, P Lidstrom. Microwave assisted organic synthesis. 1stEdition. Blackwell Publishing, Oxford; 2005. p. 311-89.

NR Pai, DS Dubhashi, S Vishwasrao, D Pusalkar. An efficient synthesis of neuroleptic drugs under microwave irradiation. J Chem Pharm Res 2010;2(5):506-17.

P Lidstrom, J Tierney, B Wathey. J Westman. J Tetrahedron 2001;57:9225–83.

R Martinez-Palou. Ionic liquids and microwave-assisted organic synthesis a green and synergic couple. J Mex Chem Soc. 2007;51:252-64.

S Balasubramanian, G Aridoss, P Parthiban, C Ramalingan, S Kabilan. Synthesis and biological evaluation of novel benzimidazol/benzoxazolylethoxypiperidone oximes. Biol Pharm Bull 2006;29(1):125-30.

S Savithiri, MA Doss, RV Thanikachalam. Synthesis, Spectral, Stereochemical and antimicrobial evaluation of some 3t-pentyl-2r,6c-diarylpiperidin-4-one Thiosemicarbazone derivatives. Can Chem Trans 2014;2(4):403-17.

CR Noller, V Baliah. The preparation of some piperidine derivatives by the mannich reaction. J Am Chem Soc 1948;70:3853-4.

Yunus Bekdemir, Kür Gat Efil. Microwave assisted solvent-free synthesis of some Imine Derivatives. Org Chem Int 2014;5: 8164-87.



How to Cite

Bhusnure, O. G., Y. B. Vibhute, P. S. Giram, A. Y. Vibhute, and S. B. Gholve. “OPTIMIZATION OF MICROWAVE ASSISTED SOLVENT-FREE SYNTHESIS OF SOME SCHIFF BASES”. International Journal of Pharmacy and Pharmaceutical Sciences, vol. 7, no. 6, June 2015, pp. 124-8, https://innovareacademics.in/journals/index.php/ijpps/article/view/5552.



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