Table 5: Physical data for Methyl 4-[2-(4-phenethylpiperazino)-1-diazenyl]benzoate (7).

Crude Mp Recryst. Crystal
No. X yield appearance IR (cm-1)
(%) (℃) Solv.
1722(C=O)
1278(C-O)
Creamy white 859(para)
7a 699&774
p-CO2CH3 97.1% 98-99 Ethanol prisms (mono-sub)