+ ArCH NAr¢ ArCHNHAr¢ CH3CN, room temp. 1 2a–e 3a–e 2,3 abcde Ar Ph Ph Ph Ph 2-furyl Ar¢ Ph 4-ClC6H4 4-BrC6H4 4-NO2C6H4 Ph 50% NaOH, TEBA J. CHEM. RESEARCH (S), 1998 57 J. Chem. Research (S), 1998, 57† Addition of Fluorene to Schiff Bases† Kostadinka Popandova-Yambolieva Department of Chemistry, University of Sofia, 1 J.Bourchier Avenue, 1126 Sofia, Bulgaria Addition of fluorene to N-arylmethylideneanilines under conditions of phase-transfer catalysis gives N-aryl-N-[9H-fluoren- 9-yl(aryl)methyl]amines 3a–e.It is known that indene and fluorene have acidic properties, but their application in the Michael addition has been little described. The addition of fluorene to some a,b-unsaturated ketones,1 nitriles and esters2 has been realized under various conditions. Some years ago we reported our preliminary results on the Michael addition of fluorene to some a,b-unsaturated ketones, esters and nitriles under conditions of phase-transfer catalysis (PTC) in acetonitrile.3 Later a similar addition was realized with other a,b-unsaturated ketones and nitriles under PTC conditions in benzene.4 There is no report in the literature on the addition of fluorene to Schiff bases.Having in mind that some fluorenyl derivatives of aminobenzoic acids are anti-inflammatory agents,5 we decided to study the behaviour of fluorene (1) towards N-arylmethylideneanilines (2). We now present the results of our studies on the reaction of 1 with 2 under PTC conditions.The expected compounds 3a–e were obtained (Scheme 1). The reaction was carried out at room temperature with an excess of aqueous sodium hydroxide, a catalytic amount of TEBA (triethylbenzylammonium chloride) and acetonitrile as solvent. For 4-methoxy- and 4-dimethylamino-benzylideneanilines only the starting Schiff bases were recovered. Also, owing to steric hindrance, there was no reaction with either N-phenylbenzophenone imine or with N-benzylidenetert- butylamine.The structures of the new compounds 3a–e were assigned by IR and 1H NMR spectroscopy and by elemental analysis. Experimental Melting points were determined by a Boetius micropoint apparatus and are uncorrected. IR spectra were recorded on a Specord 71 spectrophotometer (Carl Zeiss, Iena). 1H NMR spectra were measured with a TESLA BS 487-C spectrometer (80 MHz) using CDCl3 solutions and Me4Si as internal standard. The starting Narylmethylideneanilines were prepared by reported procedures.Typical Procedure.·Aqueous sodium hydroxide (50% w/v; 3 cm3) was added to a stirred solution of fluorene (1.66 g, 10 mmol), the corresponding Schiff base 2 (10 mmol) and TEBA (0.23 g, 1 mmol) in acetonitrile (10 cm3). The reaction mixture was stirred at room temperature for 1 h. Water (100 cm3) was added and the solid was filtered off, washed until neutral and recrystallized from methanol–ethyl acetate. The following products were obtained: N-[9H-fluoren-9-yl(phenyl)methyl]-N-phenylamine (3a) (1.48 g, 43%), mp 152–153 °C; vmax/cmµ1 (CHCl3) 3430 (NH) (Found: C, 89.78; H, 6.3; N, 3.9.C26H21N requires C, 89.9; H, 6.05; N, 4.0%); dH 3.18 (1 H, br s, NH), 4.48 (1 H, d, J 4.5 Hz), 5.18 (1 H, d, J 4.5 Hz), 6.15–7.80 (18 H, m, aromatic); N-(4-chlorophenyl)-N-[9H-fluoren- 9-yl(phenyl)methyl]amine (3b) (0.8 g, 22%), mp 162–164 °C; vmax/ cmµ1 (CDCl3) 3430 (NH) (Found: C, 81.6; H, 5.3; N, 3.6. C26H20ClN requires C, 81.7; H, 5.2; N, 3.7%); dH 3.44 (1 H, br s, NH), 4.45 (1 H, d, J 4.1 Hz), 5.08 (1 H, d, J 4.1 Hz), 6.08–7.80 (17 H, aromatic); N-(4-bromophenyl)-N-[9H-fluoren-9-yl(phenyl- )methyl]-amine (3c) (0.7 g, 17%), mp 170–172 °C; vmax/cmµ1 (CHCl3) 3420 (NH) (Found: C, 73.1; H, 4.7; N, 3.4.C26H20BrN requires C, 73.2; H, 4.7; N, 3.3%); dH 3.36 (1 H, br s, NMH), 4.40 (1 H, d, J 4.0 Hz), 5.11 (1 H, d, J 4.0 Hz), 6.10–7.80 (17 H, m, aromatic); N-[9H-fluoren-9-yl(phenyl)methyl]-N-(4-nitrophenyl)amine (3d) (0.8 g, 20%, mp 127–128 °C; vmax/cmµ1 (CHCl3) 3370 (NH), 1590 (NO2) (Found: C, 79.3; H, 5.1; N, 6.9.C26H20N2O2 requires C, 79.5; H, 5.1; N, 7.1%); N-[9H-fluoren-9-yl(2-furyl)methyl]- N-phenylamine (3e) (0.95 g, 29%), mp 178–180 °C; vmax/cmµ1 (CDCl3) 3430 (NH) (Found: C, 85.5; H, 5.7; N, 3.9. C24H19NO requires C, 85.4; H, 5.7; N, 4.1%). dH 3.46 (1 H, br s, NH), 4.68 (1 H, d, J 4.1 Hz), 5.26 (1 H, d, J 4.1 Hz), 6.04 and 6.30 (2 H, 2 d, J 6; J 6 Hz), 6.62 (1 H, d, J 14 Hz), 6.90–7.75 (13 H, m, aromatic). Received, 23rd September 1997; Accepted, 2nd October 1997 Paper E/7/06890E References 1 S. Hashimoto, K. Matsumoto, S. Otani and J. Haiami, Syntheis, 1984, 164. 2 G. Bram, J. Sansoulet, H. Galon, Y. Ben Said, G. Gomber- Farnoux and M. Miocque, Tetrahedron Lett., 1985, 26, 4601. 3 K. Popandova-Yambolieva and S. Georgieva, Proceedings of the anniversary session ‘100 years of the Faculty of Chemistry’, Sofia, 1990, pp. 113–117. 4 Ch. Yan. W. Lu and J. Wu, Org. Prep. Proced. Int., 1993, 25, 241 (Chem. Abstr., 1993, 119, 95059p). 5 J. Perumattam, US Pat., 5472 973, 1995 (Chem. Abstr., 1996, 124, p201802r). *To receive any correspondence. †This is a Short Paper as defined in the Instructions for Authors, Section 5.0 [see J. Chem. Research (S), 1998, Issue 1]; there is therefore no corresponding material in J. Chem. Research (M). Scheme 1