反应详情

A mixture of 90 g of 4-(4-chloro-2-methylphenoxy)butyric acid (Aldrich) and 1000 g of polyphosphoric acid was stirred for 4.5 h at 85° C. The batch was then poured onto 5 L of ice water, stirred for 1 h and extracted with ether. The combined organic phases were washed several times with sodium carbonate solution and water, dried over magnesium sulfate and concentrated in a rotary evaporator. The dark residue was then taken up in ether again and boiled several times with active carbon and silica gel, and filtered until the solution was only slightly colored. After concentrating, 48.4 g of 7-chloro-9-methyl-3,4-dihydro-2H-1-benzoxepin-5-one were obtained, m.p. 56-58° C. b) 3.0 g of 7-chloro-9-methyl-3,4-dihydro-2H-1-benzoxepin-5-one, 50 ml of anhydrous methanol, 10.9 g of ammonium acetate and 0.63 g of sodium cyanoborohydride were stirred for 5 h at 60° C. and then for 2 days at RT. The reaction mixture was then acidified with hydrochloric acid and then concentrated on a rotary evaporator. The residue was taken up in water, and the solution was rendered alkaline with ammonia solution and extracted with EA. After drying and concentrating, the product was purified by chromatography on silica gel using ethyl acetate/methanol 9:1 and 1.3 g of 5-amino-7-chloro-9-methyl-2,3,4,5-tetrahydro-1-benzoxepine were obtained. c) 0.86 g of ethanesulfonyl chloride was added dropwise with ice-cooling to a solution of 1.3 g of 5-amino-7-chloro-9-methyl-2,3,4,5-tetrahydro-1-benzoxepine and 2.4 g of triethylamine in 30 ml of THF. The mixture was allowed to come to room temperature and was stirred overnight, and the solvent was distilled off in vacuo. After stirring the residue with water, the deposited product was filtered off with suction and dried in vacuo. 1.6 g of 7-chloro-9-methyl-5-(N-ethylsulfonylamino)-2,3,4,5-tetrahydro-1-benzoxepine were obtained, m.p. 144-145° C. d) A solution of 0.6 g (2.0 mmol) of 7-chloro-9-methyl-5-(N-ethylsulfonylamino)-2,3,4,5-tetrahydro-1-benzoxepine in 8 ml of THF was added dropwise under nitrogen to a suspension of 0.1 g (2.7 mmol) of 80 percent sodium hydride in 5 ml of THF. After stirring at RT for 1 h, 0.41 g (2.9 mmol) of methyl iodide was added dropwise and the mixture was additionally stirred overnight at RT. After distilling off the solvent, the residue was treated with water and extracted with EA. After washing the organic phase with dil. hydrochloric acid and water, and drying over magnesium sulfate, it was concentrated in vacuo and the crude product was recrystallized from methylene chloride. 0.4 g of 7-chloro-9-methyl-5-(N-ethylsulfonyl-N-methylamino)-2,3,4,5-tetrahydro-1-benzoxepine was obtained, m.p. 141-143° C. 1H-NMR (CDCl3): δ (ppm)=1.35 (3H), 1.9-2.2 (4H), 2.2 (3H), 2.9 (3H), 3.05 (2H), 3.7 (1H), 4.2 (1H), 5.15 (1H), 7.1 (2H).

1. concentrationconcentrated on a rotary evaporator
2. extractionextracted with EA
3. customAfter drying
4. concentrationconcentrating
5. customthe product was purified by chromatography on silica gel