Table 2: Physical data for series of 1-(4-methylbenzyl)-4-(aryldiazenyl)-piperazines (4).

Crude Recryst. Crystal
No. X yield mp(℃) Appearance IR (cm-1)
(%) Solv.
4a p-CN 99.6% 83-89 (a) Dull orange 2225(CN)
Powder 842&784(para)
Hexanes & Fibrous 1707(C=O)
Pale yellow 1274(C-O)
4b p-CO2CH3 95.7% 118-119 cyclohexane Needles 827&799(para)
4c p-Br 70.6% 91-92 Isopropanol Pale yellow 832&801(para)
4d p-CH3 70.2% 93-94 Isopropanol Plates 827&790(para)
lustrous 1509 &
4e p-NO2 90.5% 124-125 Ethanol Red-brown 1379(NO2)
needles 848&795(para)
Off-white 695 & 765
4f H 93.2% 94.5-95.5 Isopropanol Needles (monosub)

(a) This compound was soluble in a variety of solvents, but it did not recrystallize from any of them.