A simple and efficient microwave-induced ruthenium trichloride-catalyzed synthesis of pyrrole fused with indole system in water is developed by reacting commercially available isatin and 4-hydroxyproline

Bandyopadhyay, Debasish

Banik, Antara

Banik, Bimal K.

Bhatta, Sahil

English

Scholarworks@UTRGV Univ. of Texas RioGrande Valley

University of Texas Rio Grande ValleyScholarWorks @ UTRGVChemistry Faculty Publications and Presentations College of Sciences1-1-2009Microwave-Assisted Ruthenium Trichloride-Catalyzed Synthesis of Pyrrole Fused With IndoleSystem in WaterDebasish BandyopadhyayThe University of Texas Rio Grande Valley, debasish.bandyopadhyay@utrgv.eduAntara BanikSahil BhattaBimal K. BanikFollow this and additional works at: https://scholarworks.utrgv.edu/chem_facPart of the Chemistry CommonsThis Article is brought to you for free and open access by the College of Sciences at ScholarWorks @ UTRGV. It has been accepted for inclusion inChemistry Faculty Publications and Presentations by an authorized administrator of ScholarWorks @ UTRGV. For more information, please contactjustin.white@utrgv.edu, william.flores01@utrgv.edu.Recommended CitationBandyopadhyay, Debasish; Banik, Antara; Bhatta, Sahil; and Banik, Bimal K., "Microwave-Assisted Ruthenium Trichloride-CatalyzedSynthesis of Pyrrole Fused With Indole System in Water" (2009). Chemistry Faculty Publications and Presentations. 34.https://scholarworks.utrgv.edu/chem_fac/34MICROWAVE-ASSISTED RUTHENIUM TRICHLORIDE-CATALYZEDSYNTHESIS OF PYRROLE FUSED WITH INDOLE SYSTEM IN WATER*Debasish Bandyopadhyay, Antara Banik, Sahil Bhatta and Bimal K. Banik*Department of Chemistry,, The University of Texas-Pan American, 1250 West UniversityDrive, Edinburg, Texas 78541; E-mail: banik&panam. eduuDedicated to the memory of Dr. R. R. GuptaAbstractA simple and efficient microwave-induced ruthenium trichloride-catalyzed synthesis ofpyrrole fused with indole system in water is developed by reacting commerciallyavailable isatin and 4-hydroxyproline.IntroductionPyrroles important classes of compounds with many medicinal activities.1 Many methodsfor the synthesis of substituted pyrroles are known in the literature.2 However, synthesisof pyrroles fused to indole system has not been explored systematically.3 In a previouspaper, we have described the preparation of these types of products using iodine in ethylalcohol.4 We describe herein a new method for the synthesis of substituted pyrrolesfused to indole skeleton by microwave-induced ruthenium trichloride-catalyzed reactionin water.Results and DiscussionWe5 have demonstrated bismuth nitrate-catalyzed synthesis of pyrroles following Paal-Knorr method. During the course of our investigation, we have identified a rutheniumtrichloride-catalyzed method for the preparationRuCI3/H20COOH MW. 10 min>80%a: Rb:Fc: R[1 =t1 =1 =H,R2H.R2CH3 >s=RHCH32 = HScheme 1121UnauthenticatedDownload Date | 10/2/19 7:31 PMVol. 15, No. 2, 2009 Microwave-Assisted Ruthenium Trichloroide-CatalyzedSynthesis of Pyrroleof pyrrole-substituted with indole using microwave-induced reactions in water (Scheme1). The reaction of isatin (1) with 4-hydroxyproline (2) in water was irradiated in thepresence of ruthenium trichloride (20 mol%) and water. The reaction was completedwithin 10 minutes. This method is therefore, unique because there are no other methodsthat describe the preparation of these types of heterocycles in water and within this shorttime. Other methods needed acidic reagents and were more time consuming.3> 4The reaction did not proceed without ruthenium trichloride. The mechanism of thereaction is not investigated.ExperimentalTo isatin (1 mmol), hydroxyproline (1 mmol), ruthenium trichlorde (20 mol%) was addedwater (2 mL) and the reaction mixture was irradiated in a CEM automated microwaveoven for 10 min (Power 300 watts and temperature 50°C). The reaction was dilutedextracted with dichloromethane and dried (Na2SC>4). Pure product (approximately, 80%)was isolated through column chromatography (ethyl acetate/hexane=30/70).6ConclusionIn conclusion, we have demonstrated synthesis of pyrrole substituted indoles usingruthenium trichloride-catalyzed microwave-induced reaction under environmentallybenign conditions.AcknowledgmentWe gratefully acknowledge the financial support for this research project from NationalInstitutes of Health -SCORE (2SO6GM008038-37).References and notes(1) For some biologically active pyrroles. See: (a) J. A. H. Lainton, J. W. Hoffman,B. R. Martin, D. R. Compton, Tetrahedron Lett., 36, 1401, (1995); (b) C. Y. DeLeon, B. Ganem, Tetrahedron, 53, 7731, (1997).(2) (a) T. L. Gilchrist, J. Chem. Soc. Perkin Trans 1, 615, (1998). (b) R. K. Dieter, H.Yu, Org. Lett., 2, 2283, (2000). (c) N. Iwasawa, K. Maeyama, M. Saitou, J. Am.Chem. Soc., 119, 1486, (1997).(3) J. Azizian, A. R. Karimi, Z. Kazemizadeh, A. A. Mohammadi, M. R.Mohammadizadeh, J. Org. Chem., 70,1471, (2005).(4) B. K. Banik, I. Garcia, F. Morales, C. Aguilar Heterocyclic Commun., 13, 109,(2007).(5) B. K. Banik, S. Samajdar, I. Banik, J Org. Chem., 69, 213, (2004).(6) The compounds 3a, 3b and 3c were found to be identical in all aspects as reportedin reference 4.Received on March 8, 2009122UnauthenticatedDownload Date | 10/2/19 7:31 PM

Microwave-Assisted Ruthenium Trichloride-Catalyzed Synthesis of Pyrrole Fused With Indole System in Water

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Microwave-Assisted Ruthenium Trichloride-Catalyzed Synthesis of Pyrrole Fused With Indole System in Water

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