Synthesis of a novel Schiff base {3,4-Bis[(2-Hydroxy-benzylidene) amino] phenyl} phenyl methanone

A mixture of (3,4-diaminophenyl) phenyl methanone 1 (2.12 g, 10.00 mmol), 2-hydroxybenzaldehyde 2 (2.44 g, 20.00 mmol) and sodium sulfate (5.00 g) in dry dichloromethane (50.00 ml) was stirred at room temperature for five hours. The suspension was filtered and washed with dichlormethane. The solvent was evaporated and compound 3 was formed as an orange solid which was recrystalized from ethanol (3.41 g, 81.30%).

m.p. 159-161^oC.

IR (KBr) (cm^-1): 1600 (C=N), 1650 (CO), 3100-3300 (OH)

¹H-NMR (CDCl₃) (250 MHz)δ(ppm): 6.95-7.76 (16H, m, 4Ph), 8.59 (2H, s, N=CH), 12.71 (2H, br, OH)

¹³C-NMR (CDCl₃) (62.90 MHz)δ(ppm): 115.00-144.25 (aromatic carbons), 159.45 (C-OH), 163.05 (C=N), 193.00 (CO).

MS (m/z, %): 420 (M ⁺, 8.40), 314 ( PhCOPh(N)(N=CHPhOH, 100.00), 237 (PhCOPh(N=CH)₂, 70.00) , 209 (PhCOPh(N)₂, 23.50 ), 182 (PhCOPh, 5.00), 105 (PhCO, 41.20), 77 (PhH)