2-Isopropylaniline → 2-Isopropylphenylhydrazine

A mixture of the substituted aniline, 2-isopropylaniline (27g, 0.2 mole), concentrated hydrochloric acid (150 ml) and water (160 ml) is stirred mechanically for 30 minutes at room temperature. After cooling to 0° C., the mixture is diazotized by adding dropwise a solution of sodium nitrite (14 g, 0.203 mole) in water (140 ml) over a period of 20 minutes. Stirring is continued for an additional one hour at 0° C. The diazo solution is reduced by adding dropwise a solution of stannous chloride dihydrate (112 g, 0.497 mole) in concentrated hydrochloric acid (90 ml) over a period of 30 minutes at -10° C. to -15° C. The reaction mixture is stirred for an additional 1.5 hour at -10° C. to -15° C. The precipitate is collected by filtration to give the hydrochloric acid addition salt of the title compound. The salt is purified further by dissolving it in ethanol, concentrating the solution and adding a saturated solution of hydrochloric acid in ether to give the hydrochloride salt with mp 206°-210° C.