Table 5: Summary of physical and IR spectroscopic data of the 1-(ortho-tolyl)-4-(2-aryl-1-diazenyl)-piperazine series (16).

Series #	X	% Yield	M.P. (°C)	Recr. Solv.	Crystal Appearance	IR (cm-1)
16a	p-NO2	46	143.0 - 144.1	Cyclohexane	Blood-red Needles	OOP NO2	855 1321, 1507
16b	p-Cl	60	104.9 - 105.5	Ethanol	Creamy yellow needles	OOP	846
16c	p-CO2C2H5	62	105.5 - 106.1	Ethanol	Large orange needles	OOP C=O C-O	859 1711 1269
16d	p-COCH3	53	115.1 - 115.9	Ethanol	Red-gold lustrous needles	OOP C=O	845 1675
16e	p-CONH2	11	222.2 - 223.4	Ethanol	Orange prisms	OOP C=O N-H	857 1658 3289, 3328
16f	p-OCH3	53	131.6 - 133.2	Cyclohexane	Dark red prisms	OOP C-O	833 1010, 1242
16g	H	61	Oil	Oil	-	OOP	813