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Microwave-Assisted Urea Catalyzed Knoevenagel Condensation of Aldehydes with ＝ Light Brown Solid, M.P

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Microwave-Assisted Urea Catalyzed Knoevenagel Condensation of Aldehydes with ＝ Light Brown Solid, M.P Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 55(2), 159-164, 2020 purification. The Chemicals 4-fluorobenzaldehyde (98%), 2-(4-nitrophenylmethylene)malononitrile (3a): yield 90%, 2-(4-Hydroxyphenylmethylene)malononitrile (3f): yield CDCl3) δ(ppm): 8.32(s, 1H), 8.01(d, J=8.4, 2H), 7.22(d, Furthermore, the treatment of aldehyde such as acknowledge the University Research Centre, SUST for Yang Y, Dong ODW, Pan W, Zhang J and Liu Q (2006), Wang C, Li Guishen S, Li G, Feng J, Li S and Xiaolu (2001), 4-hydroxybenzaldehyde (98%), 4-nitrobenzaldehyde yellowish white solid, m.p. 158-159 , (lit.160 (Sun Qi et 96%, yellow solid, m.p. 171-172 , (lit. 189-190 ( Sun J=8.4, 2H), 6.38(s, 1H, N-H), 6.11(s, 1H, N-H) . cinnamaldehyde with ethylcyanoacetate also give financial support. Facile and clean synthesis of α-alkenoyl Synthesis of 5-alkylene barbituric acid in solventless 2 Qi et al 2005 ); IR (KBr): υ (cm-1): 3354(-OH), olefinic compounds 3i under similar conditions (Table ketene-(S,S)-acetal via the aldol condensation under microwave irradiation, Chin. J. Org. Chem. (98%), 2-nitrobenzaldehyde (98%), 3-nitrobenzaldehyde al 2005)); IR (KBr): υmax: 3039(sp C-H), 2231 (C≡N), 1604 max (98%), 4-chlorobenzaldehyde (97%) and cyanoacetamide (C=C) and 1521 and 1344(N-O) cm℃-1; 1H NMR℃ (400 MHz, 3030(sp2 C-H), 2227(C≡N), and℃ 1670(C=C) cm℃-1; 1H 2-cyano-3-(4-nitrophenyl)acrylamide (3l): yield 85%, 1, Scheme 1). Both electron-rich and References reactions in water, Tetrahedron 62: 10-111. 21(4): 310-312. Microwave-assisted urea catalyzed Knoevenagel condensation of aldehydes with ＝ light brown solid, m.p. 229-230 , ; IR (KBr): υ (cm-1): electron-deficient aldehydes gave high yield of (98%) from Sigma-Aldrich, Cinnamaldehyde (98%), and CDCl ) δ(ppm): 8.41 (2H, d, J = 8.8Hz, =CH), 8.09 (2H, d, J NMR (400 MHz, CDCl3) δ(ppm): 7.89 (2H, d, J 9.0 Hz, max 3 ＝ ＝ 3442and 3346 (N-H str., NH ), 3196 (aromatic C-H str.), Acker DS and Hertler WR, (1962), Substituted active methylene compounds ethylcyanoacetate from Merck, 2-furaldehyde (98%), = 8.8Hz, Ar), 7.89 (1H, s, -CH). Ar), 7.65 (1H, s, CH), 6.97 (2H, d, J 9.0 Hz, Ar), 2 products. Heterocyclic aldehydes such as ℃ quinodimethans. I. Preparation and chemistry of 7, 7, 4-methylbenzaldehyde (98%), 4-methoxybenzaldehyde 5.75 (1H, s, OH). 3024 (sp2 C-H str.), 2224 (C≡N str.), 1695 (CO str.), 2-furaldehyde and pyridine-4-carboxaldehyde gave 8, 8-tetracyanoquinodimethan. Journal of the (99%) and malononitrile (99%) were purchased from Alfa 2-(4-methylbenzylidene)malononitrile (3b): yield 96%, 1622 (alkene C=C str.), 1600 and1494 (aromatic C=C the olefinic derivatives 2-furylmethylene, 3g and W. T. Purba, P. S. Roy, S. Jannat, S. A. Begum and M. M. Rahman 2-(2-Furylmethylene)malononitrile (3g): yield 90%, str.), 1510 and 1346 (nitro N=O str.), 1327 (C-N str), 2-(3—pyridylmethylene) olefinic 3h derivatives at American Chemical Society 84(17): 3370-3374. DOI: * Aser. GALLEN KAMP melting point apparatus was used white solid, m.p. 131-132 , (lit.134 (Ren et al 2002)); IR -1 2 3 blackish brown solid, m.p. 62-63 , (lit. 72 ( Sun Qi et 1 90% and 95% yield respectively. Similar reaction of 10.1021/ja00876a028 (KBr): υ (cm ): 3035(sp C-H), 2927(sp C-H), 2223(C≡ 1203 (C-O str.), H NMR (400 MHz, CDCl3) δ(ppm): Department of Chemistry, Shahjalal University of Science & Technology, Sylhet 3114, Bangladesh to record the melting point of the solid compound, the max -1 2 ℃-1 1 ℃ al 2005 ); IR (KBr): υmax(cm ): 3124(sp C-H), 2223 (C≡ 8.39(d, J= 8.8 Hz, 2H), 8.30(s, 1H), 8.13(d, J=8.8, 2H), 4-hydroxy, 4-fluoro, 4-nitro, and 2–furylaldeydes with heating was done carefully to ensure a steady rise of N) and 1589(C=C) cm ; H NMR (400 MHz, CDCl3) N) 1606 (C=C) and 1151(C-O-C)℃ cm-1; 1℃H NMR (400 active methylene compounds 2-cyanoacetamide gave Ahmed MR, Nasiruddin N, Alim MA, Jaman N, Islam MA, 1 δ(ppm): 7.80 (2H, d, J= 8.2Hz, Ar), 7.71 (1H, s, =CH), 7.32 8.05(s, 1H, N-H), 7.91(s, 1H, N-H). temperature. H NMR spectra were recorded on a JEOL MHz, CDCl ) δ(ppm): 7.80 (1H, d, J= 1.6 Hz, Ar), 7.50 the corresponding olefins derivatives 2-cyano Begum SA, Rahman MM, Ahmed MF and Mannan (2H, d, J=8.2 Hz, Ar.), 2.44 (3H, s, -CH ); 3 Abstract JNM ECS FT NMR at 400 MHz spectrometer using 3 (1H, s, =CH); 6.70 (1H, dd, J= 3.6 & 1.6 Hz, Ar), 7.35 2-cyano-3-(furan-2-yl)acrylamide (3m): yield 88%, light (3-(hydroxyphenyl)- propaneamide (3j), 2-cyano MA (2018), Facile and rapid Synthesis of arylidene tetramethylsilane as an internal standard. Coupling -1 (1H, d, J=4.0Hz, Ar). brown solid, m.p. 93-94 ; IR (KBr): υ (cm ): 3488and (3-(4-fluorophenyl)- propaneamide (3k), 2-cyano derivatives by microwave assisted NH4OAc catalyzed Rapid and efficient method for the synthesis of substituted olefins such as 2-(4-fluorobenzylidene)malononitrile (3c): yield 94%, light max constants J are given in Hz. Infrared spectra were 3381 (N-H str. For NH ), 3169 (aromatic C-H str.), 3024 (3-(4-nitrophenyl)- propaneamide (3l), and 2-cyano under solvent free condition, Organic Chem: Curr Res 2-(4-chlorophenylmethylene) malononitrile, 2-(4-hydroxyphenylmethylene) malononitrile and brown solid m.p. 119 , (lit.124-125 (Fan et al 2004); IR 2 observed on a Shimadzu FTIR- spectrometer (IR prestige 2-(3-pyridylmethylene)malononitrile (3h): yield 95%, ℃ (3-(furylphenyl)- propaneamide (3m) respectively. pp 7-3. 2-cyano-3-(4-hydroxyphenyl) acrylamide etc under the influence of microwave irradiation are (KBr): υ (cm-1): 3043(sp2 C-H), 2231 (C≡N) and 1658 (sp2 C-H str.), 2216 (C≡N str.), 1701 (CO str.), 1687 max brownish solid, m.p. 80-82 , (lit. 83-84 ( SunQi et al described. Urea has been utilized as an efficient catalyst for the Knoevenagel condensation of 21). Analytical TLC was performed on pre-coated alumina -1 1 ℃ ℃ (alkene C=C str.), 1600 and1504 (aromatic C=C str.), Nitro, hydroxyl, heterocyclic group are well tolerable (C=C) cm ; H NMR (400 MHz, DMSO) δ(ppm): 8.53 (1H, s, -1 2 1 Borah HN, Deb ML, Boruah RC and Bhuyan PJ (2005), aldehydes with acidic active methylene compounds such as malononitrile, ethylcyanoacetate and sheet and the product was visualized by UV light. All 2005 ); IR (KBr): υmax(cm ): 3032(sp C-H), 2227 (C≡N) 1386 (C-N str), 1233 (C-O str.). H NMR (400 MHz, due to the short reaction time and relatively mild =CH), 8.02-8.06 (2H, t, J=8 Hz, Ar), 7.48-7.52 (2H, m, Ar). 1 ℃ ℃ Stereoselective intramolecular hetero Diels–Alder cyanoacetamide to afford substituted olefins under the influence of microwave irradiation. The reactions were carried out in a domestic microwave oven 1589 (C=C) ; H NMR (400 MHz, CDCl3) δ(ppm): 8.89 reaction conditions. The reaction does not proceed CDCl3) δ(ppm): 8.10(s, 1H), 7.76(d, J=1.6, 1H), 7.25(d, reaction proceeds smoothly under mild and solvent free conditions and the products are obtained in (1H, d, J= 2.4 Hz, Ar), 8.83 (1H, dd, J = 1.2 & 4.8 Hz, under similar condition in the absence of urea catalyst. reactions of 1-oxa-1, 3-butadienes: synthesis of novel Received: 29 September 2019 (Samsung, MW76ND). 2-(4-Chlorophenylmethylene)malononitrile (3d): yield J=3.6, 1H), 6.66(dd, J=3.6, J=1.6, 1H), 6.29(s, 1H, good yield. The method is applicable for a wide range of aldehydes including aromatic and Ar), 8.50 (1H, dd, J = 1.5 , 8.0 Hz, Ar).7.83 (1H, s, =CH), The reaction does not take place at all, only starting annelated pyrrolo [1, 2-a] indoles. Tetrahedron letters, Revised: 27 October 2019 heterocyclic substrates. 95%, white solid, m.p. 158-160 , (lit. 165 (Sun Qi et al N-H), 5.76(s, 1H, N-H). General procedure 7.53(1H, dd, J = 4.8, 7.8 Hz, Ar). materials obtained in reaction mixture. 46(19): 3391-3393. Accepted: 11 Nobember 2019 2005); IR (KBr): υ (cm-1): 3034(sp2 C-H), 2227 (C≡N) max Results and discussion Keywards: Microwave; Active methylene; Green procedure; Urea catalyst; Substituted -1 1 ℃ ℃ 1 To a mixture of aromatic aldehyde 1 (2 mmol) and active and 1585 (C=C) cm ; H NMR (400 MHz, CDCl3) δ(ppm): Ethyl 2-cyano-3-styryl-2-propenoate (3i): yield 92%, All the products were characterized by IR and H NMR Bhuiyan MMH, Hossain MI, Alam MA and Mahmud MM DOI: https://doi.org/10.3329/bjsir.v55i2.47637 cyanoacetamide; Knoevenagel condesation ＝ ＝ 1 methylene compound 2 (2 mmol) was added catalytic 7.72(1H, s, CH), 7.83 (2H, d, J 8 Hz, Ar), 7.53 (2H, yellowish solid m.p. 111-112 , (lit.115 (Sun Qi et al In this report, we highlight our findings on the data analysis. The H NMR spectra of the products 3a – 3i (2012), Microwave assisted Knoevenagel d, J＝8 Hz, Ar) . -1 2 condensation: Synthesis and antimicrobial activities of amount of urea(10 mol %, 0.2 mmol) in a Pyrex glass 50 2005); IR (KBr): υmax (cm ): 3030(sp C-H), 2250 (C≡N), microwave assisted urea catalysed condensation of showed the olefinic proton around δ 7 – 9 ppm in CDCl3 ℃ -1 1 ℃ mL beaker and mixed thoroughly using a glass rod.
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