Treatment of 2-amino-5-bromopyridine (I) with 2-(1-cyclohexenyl)ethyl isothiocyanate (II) in hot N-methylpyrrolidinone produced the target thiourea.
Treatment of 2-amino-5-chloropyridine (I) with 2-(1-cyclohexenyl)ethyl isothiocyanate (II) in N,N-dimethylformamide at 90 C produced the target thiourea.
2,6-Difluorophenethylamine (II) was prepared by reduction of nitrile (I) with either NaBH4 in the presence of CoCl2 or borane in THF. Reaction of amine (II) with thiocarbonyldiimidazole (III) furnished the thioimidazolide (IV). This was finally condensed with 2-amino-5-chloropyridine (V), yielding the corresponding thiourea.
Alternatively, 2-amino-5-bromopyridine (I) was reacted with 1,1'-thiocarbonyldiimidazole (III) in acetonitrile yielding thioimidazolide (IV), which was then condensed with 2-(1-cyclohexenyl)ethylamine (V) in hot DMF.
Alternatively, 2-amino-5-chloropyridine (I) was reacted with 1,1'-thiocarbonyldiimidazole (III) in acetonitrile yielding thioimidazolide (IV), which was then condensed with 2-(1-cyclohexenyl)ethylamine (V) in hot DMF.