2,2,4-Trimethyl-1,2-dihydroquinoline → Quinoline, 1,2,3,4-tetrahydro-2,2,4-trimethyl-

Beteiligte Stoffe

Reaktionsschritte

In 10 ml of ethanol was dissolved 2.0 g (11.5 millimoles) of 1,2-dihydro-2,2,4-trimethylquinoline, and 0.4 g of 10% Pd-C was added to the solution and reaction was carried out at 60° C. in a hydrogen atmosphere for 7 hours. The catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to obtain 1.8 g (the yield was 89%) of 2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline in the form of a light-brown oil. To 0.5 g (3.7 millimoles) of 4-hydroxymethylimidazole hydrochloride was added 3 ml of thionyl chloride and reaction was carried out at 50° C. for 2 hours. The excess of thionyl chloride was removed by distillation under reduced pressure. The residue was dissolved in 10 ml of DMF and a solution of 1.1 g (6.3 millimoles) of 2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline in 5 ml of DMF was added to the above solution at 100° C. Reaction was carried out for 1 hour. DMF was removed from the reaction mixture by distillation under reduced pressure. An aqueous solution of sodium hydrogen-carbonate was added to the residue and the mixture was extracted with dichloromethane. The organic layer was dried with anhydrous sodium sulfate and concentrated under reduced pressure to obtain a light-green oil. The oil was purified by the silica gel column chromatography (developing solvent; ethyl acetate) to obtain 0.35 g (the yield was 39%) of 4-[1-(2,2,4-trimethyl-1,2,3,4-tetrahydroquinolyl)methyl]imidazole in the form of a colorless crystal. Reaction was carried out in the same manner as described in Example 3 by using 4-[1-(2,2,4-trimethyl-1,2,3,4-tetrahydroquinolyl)methyl]imidazole to obtain 0.35 g (the yield was 30%) of intended compound No. 8 in the form of a light-brown oil.

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