4-hydroxy-2,2-dimethylbutanoic acid

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A mixture of 2,2-dimethylbutyrolactone (6.84 g, 60 mmol) and KOH (3.36 g) in H2O (60 mL) was heated at reflux for 2 h. The solution was cooled to room temperature and acidified to pH 5 with aqueous HCl solution. The mixture was then extracted with ethyl acetate 3 times. The combined organic layers were washed with brine, dried over Na2SO4, concentrated under reduced pressure to give 4-hydroxy-2,2-dimethyl-butanoic acid compound 54-B (4 g). was heated at reflux for 2 h The mixture was then extracted with ethyl acetate 3 times The combined organic layers were washed with brine dried over Na2SO4 concentrated under reduced pressure

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A mixture of benzyl bromide (37.4 g) and 4-hydroxy-2,2-dimethylbutanoic acid, monopotassium salt, (3.4 g) in dimethylformamide (35 mL) was stirred at room temperature for 18 hours. The precipitate was filtered off and the filtrate was evaporated. The residue was chromatographed on silica gel eluting with 2:1 dichloromethane:ethyl acetate to give 3.95 g (89%) of 4-hydroxy-2,2-dimethylbutanoic acid phenylmethyl ester as a colorless oil. A sample was evaporatively distilled to give the analytical sample: bp 160°-165° C./0.25 mm; IR (CHCl3) 3595 (OH), 1707 (C=O) and 687 cm-1 (C6H5); NMR (CDCl3) δ 1.23 (s, 6, CH3), 1.85 (t, 2, CH2), 3.67 (t, 2, CH2), 5.11 (s, 2, CH2) and 7.34 (s, 5, Ph); MS m/e 222,91. The precipitate was filtered off the filtrate was evaporated The residue was chromatographed on silica gel eluting with 2:1 dichloromethane

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Step B To the mixture of 4-hydroxy-2,2-dimethyl-butanoic acid (2.2 g, 16.6 mmol) in ethyl ether (16 mL) and methanol (24 mL) at 0° C. was added a hexane solution (2.0 M) of trimethylsilyldiazomethane (Aldrich) (12.5 mL, 25 mmol). The reaction mixture was stirred at 0° C. for 1 h. The solvents were evaporated. The residue was taken up in ethyl acetate, washed with diluted aqueous HCl solution, saturated aqueous NaHCO3 solution, brine, dried over MgSO4, and concentrated to give 4-hydroxy-2,2-dimethyl-butyric acid methyl ester as a colorless oil (1.5 g, 62%). The solvents were evaporated washed with diluted aqueous HCl solution, saturated aqueous NaHCO3 solution, brine dried over MgSO4 concentrated

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Step A A mixture of 2,2-dimethylbutyrolactone (6.84 g, 60 mmol) and KOH (3.36 g) in H2O (60 mL) was heated at reflux for 2 h. The solution was cooled to room temperature, and acidified to “pH” 5 with aqueous HCl solution. The mixture was then extracted with ethyl acetate three times. The combined organic layers were washed with brine, dried over MgSO4, concentrated under reduced pressure to give 4-hydroxy-2,2-dimethyl-butanoic acid as a colorless oil (4 g, 51%). was heated at reflux for 2 h The mixture was then extracted with ethyl acetate three times The combined organic layers were washed with brine dried over MgSO4 concentrated under reduced pressure

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A mixture of 2,2-dimethylbutyrolactone (6.84 g, 60 mmol) and KOH (3.36 g) in H2O (60 mL) was heated at reflux for 2 h. The solution was cooled to room temperature and acidified to pH 5 with aqueous HCl solution. The mixture was then extracted with ethyl acetate 3 times. The combined organic layers were washed with brine, dried over Na2SO4, concentrated under reduced pressure to give 4-hydroxy-2,2-dimethyl-butanoic acid compound 54-B (4 g). was heated at reflux for 2 h The mixture was then extracted with ethyl acetate 3 times The combined organic layers were washed with brine dried over Na2SO4 concentrated under reduced pressure

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A mixture of benzyl bromide (37.4 g) and 4-hydroxy-2,2-dimethylbutanoic acid, monopotassium salt, (3.4 g) in dimethylformamide (35 mL) was stirred at room temperature for 18 hours. The precipitate was filtered off and the filtrate was evaporated. The residue was chromatographed on silica gel eluting with 2:1 dichloromethane:ethyl acetate to give 3.95 g (89%) of 4-hydroxy-2,2-dimethylbutanoic acid phenylmethyl ester as a colorless oil. A sample was evaporatively distilled to give the analytical sample: bp 160°-165° C./0.25 mm; IR (CHCl3) 3595 (OH), 1707 (C=O) and 687 cm-1 (C6H5); NMR (CDCl3) δ 1.23 (s, 6, CH3), 1.85 (t, 2, CH2), 3.67 (t, 2, CH2), 5.11 (s, 2, CH2) and 7.34 (s, 5, Ph); MS m/e 222,91. The precipitate was filtered off the filtrate was evaporated The residue was chromatographed on silica gel eluting with 2:1 dichloromethane