Synthesis of 2(3H)- and 2(5H)-furanone derivatives Section A-Research paper Eur. Chem. Bull., 2014, 3(11), 1064-1068 1064 SYNTHESIS AND REACTIONS OF SOME 2(3H)- AND 2(5H)- FURANONE DERIVATIVES: A COMPARATIVE STUDY Ahmed I. Hashem, [a] Wael S. I. Abou-Elmagd [a] and Ahmed Abd-Elaziz [a] Keywords: 2(5H)-furanone, 2(3H)-furanone, nitrogen, nucleophiles, unfavored 1,4- addition , thiazolidine and tetrazole rings.. Early, it was found that benzoin condensed with ethyl cyanoacetate in the presence of ethoxide ion to give 3- cyano-3,4-diphenyl-2(5H)- furanone 1. On reinvestigating this reaction, we were able to isolate 1 together with another product, in low yield, which was proved to be 3-cyano-3,4-diphenyl-2(3H)-furanone 2. The latter is formed by isomerization of 1 under the basic conditions employed. Energy calculations revealed that the 2(5H)-furanone 1 is more stable than the 2(3H)-isomer by 24.5 KJ/mole. The behavior of the two furanones 1 and 2 towards some nitrogen nucleophiles viz. hydrazine hydrate, benzylamine and ammonium acetate is studied. The unfavored 1,4 addition of these nucleophiles to the α,β-unsaturated carbonyl moiety of 1 is explained in terms of steric and electronic effects of the phenyl group at position 4 .The nitrile groups at position 3 of the furanones 1 and 2 were utilized to construct thiazolidine and tetrazole rings by the action of thioglycollic acid and sodium azide respectively. The structures of all the products obtained were illustrated from their analytical and spectral properties. Corresponding Authors Tel./Fax: +20224831836 E-Mail: waelmagd97@yahoo.com [a] Chemistry Department, Faculty of Science, Ain Shams University, Abassia, Cairo, Egypt, post code 11566. Introduction Furanones represent a group of heterocyclic compounds of special importance. According to the relative positions of the carbonyl group and the double bond in the hetero ring, there are three types of furanones namely; 2(3H)-,2(5H)- and 3(2H)- furanones. Compounds of the first type are characterized by facile ring opening to give acyclic products which can be recyclized to give heterocyclic derivatives of synthetic and biological importance. The nucleus of the second type is the core skeleton in many natural products. The chemistry of the first two types had been reviewed by one of us. 1,2 Also, our research group were interested during the last decades in the utilization of 2(3H)- furanone derivatives in the construction of a variety of heterocyclic systems, viz. pyrrolinones, 3,4 pyridazinones, 5,6,7 isothiazolones, 8 ,oxadiazoles, 9,10 and triazoles . 11,12 Experimental section General Melting points were measured on a Gallen Kamp electric melting point apparatus. The infrared spectra were recorded using potassium bromide disks on FTIR Thermo Electron Nicolet 7600 (USA) infrared spectrometer. The 1 H-NMR spectra were run at 300 MHz on a GEMINI 300 BB NMR spectrometer using tetramethyl silane (TMS) as internal standard in deuterated dimethylsulphoxide (DMSO-d 6 ). The mass spectra were recorded on a shimadzu GC-MS QP- 1000EX mass spectrometer operating at 70 eV. The reactions were monitored by the thin layer chromatography using Merck Kiesel gel 60 F254 aluminum backed plates. General procedure for condensation of benzoin with ethyl cyanoacetate. 13 A mixture of (0.1 mol, 21.2 g) of benzoin in 70 ml of absolute alcohol there was added (0.1 mol, 11.3 ml) of ethyl cyanoacetate followed by 2.3 g of sodium dissolved in 70 ml of absolute alcohol. There was a momentary purple color on adding sodium and heat is developed. On shaking the benzoin dissolved to form a clear reddish solution. This was heated on the water bath under reflux condenser for three hours, after which it was poured into 800 ml of water. A small precipitate of unchanged benzoin was filtered off and the clear filtrate acidified. A granular semi-solid precipitate was filtered off, rubbed with a small amount of ether and the white crystals filtered from ether yield about 85 %. Recrystallization from methanol yielded 3-cyano-4,5- diphenyl-2(5H)- furanone 1. Another precipitate was collected from ether layer and recrystallized from methanol to give 3-cyano-4,5-diphenyl-2(3H)- furanone 2. 3-cyano-4,5-diphenyl-2(5H)- furanone, (1). White crystals; m.p: 139-140 o C, yield 85 %. IR (KBr) ( max , cm -1 ): 2235 (CN), 1770 (C=O lactone), 1621 (C=C). 1 H-NMR (DMSO-d 6 ):  H (ppm) 6.17 (s, 1H,CH-Ph) 6.95- 7.40 (m, 10H, ArH). MS, m/z (%): 261 (M .+ , 57), 217 (31), 91(24), 77 (100) . Anal. Calcd. For C 17 H 11 NO 2 (261): C, 78.15; H, 4.24; N, 5.36. Found: C, 78.30; H, 4.33; N, 5.76. 3-cyano-4,5-diphenyl-2(3H)- furanone, (2). Yellow crystals; m.p:167-169 o C, yield 15 %. IR (KBr) ( max , cm -1 ): 2252 (CN), 1782 (C=O lactone), 1623 (C=C). 1 H-NMR (DMSO-d 6 ):  H (ppm) 4.23 (s, 1H,CH-CN) 7.09- 7.47 (m, 10H, ArH). MS, m/z (%): 261 (M .+ , 39), 217 (54), 191(31),77 (100) . Anal. Calcd. For C 17 H 11 NO 2 (261): C, 78.15; H, 4.24; N, 5.36. Found: C, 77.96; H, 4.17; N, 5.56.