4.2.1. Synthesis Procedure of the 9H-Fluoren-9-one Oxime and Spectral Data

In a round-bottomed, 4-necked flask fitted with a shaker, thermometer, water-cooled condenser, and drip funnel, are placed 5 g of 9-fluorenone (molecular weight (Mw) 180.19) (0.028 mol) dissolved in 20 mL of methanol, over which gradually add, under stirring, 5.5 g of sodium hydroxide (Mw 39.99). Over the mixture, gradually add, with stirring, at 75–80 °C, 2.5 g of hydroxylamine hydrochloride (Mw 69.49) (0.036 mol), dissolved in 10 mL of methanol. Then, the reaction mixture was refluxed for 5 h. After cooling to room temperature, a mixture of 12.5 mL hydrochloric acid and 27 mL of water is gradually added until pH 8, when the oxime precipitates. The mixture stirs at room temperature for one hour, and then, the oxime is filtered under low pressure and washed thoroughly on the filter with water. After isolating the precipitate, it was dried, then purified from xylene.

Result 4.80 g of compound (Mw 195.22), crystallized, yellow, in 88.5% yield, T.t. 194.3–195.2 °C, soluble in cold ethyl acetate, DMF, DMSO, pyridine and in hot methanol, ethanol, isopropanol, isobutanol, chloroform and xylene, insoluble in hexane and water.

¹H-NMR (DMSO-d6, δ ppm, J Hz): 12.58 (s, N-OH); 8.37 (d, J = 7.3 Hz, 1H, H-1); 7.90 (d, J = 7.6Hz, 1H, H-4); 7.85 (d, J = 7.6, Hz, 1H, H-5 or H-8); 7.73 (d, J = 7.3 Hz, 1H, H-5 or H-8); 7.32–7.54 (m, 4H, H-2, H-3, H-6, H-7).

¹³C-NMR (DMSO-d6, δ ppm): 150.96 (C-9); 140.13 (C-4a); 139.25 (C-5a); 135.28 (C-8a); 130.73 (C-1a); 129.65 (C-6 or C-7); 129.60 (C-6 or C-7); 128.48 (C-1); 128.35 (C-2); 127.98 (C-3); 120.80 (C-4); 120.38 (C-5 or C-8); 120.31 (C-5 or C-8).

FT-IR (solid in ATR, ν cm⁻¹): 3166w; 3039w; 2617m; 1642m; 1603m; 1588vs; 1485s; 1433m; 1319m; 1167s; 1090m; 1001s; 947s; 873s; 737w; 676vs; 621vs.