An activated trifluoromethyl group as a new synthon for 4,5‐dihydro‐1H‐imidazole and 1,4,5,6‐tetrahydropyrimidine systems

Treatment of 4‐(trifluoromethyl)benzenamine 1a and 2‐(trifluoromethyl)benzamine 1b with lithium 2‐aminoethylamide gives 2‐(4‐aminophenyl)‐4,5‐dihydro‐1H‐imidazole 3a and 2‐(2‐aminophenyl)‐4,5‐dihydro‐1H‐imidazole 3b, respectively. Similar reactions of 1a and 1b with lithium 3‐aminopropylamide produce the respective 2‐(aminophenyl)‐1,4,5,6‐tetrahydropyrimidines 4a and 4b. 3‐(Trifluoromethyl)benzenamine 1c is recovered unchanged from analogous mixtures. The mechanism is discussed.