Reaction of 2,6-dinitrotoluene (I) with hydroxylamine and KOH provides 2,4-dinitro-3-methylaniline (II). Sandmeyer reaction of aniline (II) with tert-butyl nitrite and CuCl2 leads to aryl chloride (III). Selective reduction of one nitro group by transfer hydrogenation with cyclohexene and Pd/C affords the nitro aniline (IV). Further diazotization of (IV), followed by hydrolysis of the resultant diazonium fluoroborate in aqueous H2SO4 yields 4-chloro-2-methyl-3-nitrophenol (V). The intermediate clorophenol (V) can be alternatively prepared by chlorination of 2-methyl-3-nitrophenol (VI) with N-chlorosuccinimide in the presence of triflic acid. Alkylation of phenol (V) with bromoacetonitrile produces the aryloxyacetonitrile (VII). Nitro group reduction in (VII) with Zn/AcOH, followed by acylation of the resultant aniline (VIII) with mesyl chloride in pyridine leads to sulfonamide (IX). Then, Me3Al-catalyzed addition of ethylenediamine to nitrile (IX) generates the target imidazoline, which is finally isolated as the corresponding hydrochloride salt. (1)
In a related method, 2-methyl-3-nitrophenol (I) is reduced to the corresponding amine (II) by catalytic hydrogenation over Pd/C. Alkylation of phenol (II) with bromoacetonitrile provides the aryloxyacetonitrile (III). The amino group of (III) is then acylated by methanesulfonyl chloride producing sulfonamide (IV). Subsequent chlorination of (IV) employing tert-butyl hypochlorite leads to aryl chloride (V). Nitrile (V) is further converted into imidate (VI) with HCl/EtOH. Finally, reaction of imidate (VI) with ethylenediamine provides the target imidazoline. (1)