反应详情

To a slurry of NaH (60% in oil) (6.92 g, 288.28 mmol) in anhydrous THF (1500 ml) at 0° C. under argon with vigorous mechanical stirring added the trimethyl phosphonoacetate (52.50 g, 288.28 mmol) dropwise. Stirred this mixture an additional 30 minutes before adding the 1,4-cyclohexanedione mono-ethylene ketal (40.93 g, 262.07 mmol) in THF (170 ml) dropwise. The mixture was stirred an additional 18 h at 20° C. and then concentrated under reduced pressure. This residue was taken up in diethyl ether (1000 ml) and washed consecutively with H2O and brine, dried (MgSO4), filtered and concentrated to give 60.08 g (98%) of the unsaturated ester 1 which was carried on without further purification. To a solution of unsaturated ester 1 in EtOAc (500 ml) added the palladium (10 wt. % on activated carbon) (2.13 g). This slurry was saturated with H2 by repeated evacuations and H2 backfills and then stirred for 16 h under one atmosphere pressure of H2. Celite (5 g) was added to the reaction, the palladium was filtered off and the filtrate was concentrated under reduced pressure to give 59.45 g (98%) of the saturated ester 2 which was carried on without further purification. To a solution of LiAlH4 (200.00 ml, 1 M in diethyl ether) at −78° C. under argon was added the unsaturated ester 2 in anhydrous THF (400 ml) in a slow stream with vigorous mechanical stirring. Upon warming to 20° C. additional THF (600 ml) was added and the reaction was stirred 1 h. The mixture was cooled to 0° C. and quenched by the careful, consecutive addition of H2O (7.60 ml), NaOH (7.60 ml of a 15% aqueous solution), and an additional portion of H2O (22.80 ml). The solids were filtered off and the filtrate was concentrated under reduced pressure. Subsequent purification by chromatography on SiO2 with 20-50% EtOAc:hexanes gave 50.93 g (98%) of the alcohol 3 as a pale oil. To a solution of oxalyl chloride (20.65 ml, 41.29 mmol) in anhydrous CH2Cl2 (100 ml) at −78° C. under argon was added dropwise a solution of DMSO (6.72 g, 86.02 mmol) in CH2Cl2 (25 ml). After mechanical stirring for 15 minutes a solution of the alcohol 3 (6.40 g, 34.41 mmol) in CH2Cl2 (80 ml) was added dropwise and the mixture was stirred an additional 15 min at −78° C. before adding triethylamine (27.85 g, 275.30 mmol). The reaction was stirred 2 h at 20° C. and then quenched with saturated aqueous NaHCO3. This mixture was extracted CH2Cl2 and the combined organic fractions were washed consecutively with H2O and brine, dried (MgSO4) and concentrated under reduced pressure. The resulting solids were purified by chromatography on SiO2 with 20-30% EtOAc:hexanes to give 5.08 g, (79%) of the aldehyde 4 as a white solid. A solution of aldehyde 4 (5.08 g, 27.59 mmol) in EtOH (40 ml) was treated with tosylmethyl isocyanide (TosMIC) (5.15 g, 26.27 mmol) and NaCN (0.13 g, 2.68 mmol) at 20° C. for 3 h and then refrigerated. After 2 h refrigeration the solids were filtered off, dissolved in anhydrous MeOH saturated with NH3 (30 ml) and heated in a sealed tube at 100° C. for 3.5 h. The reaction was then concentrated under reduced pressure and the residues were taken up in CHCl3, washed consecutively with saturated aqueous NaHCO3 and brine, dried (MgSO4) and concentrated to a red oil. This-residue was further purified by chromatography on SiO2 with 5-10% MeOH (saturated with NH3): CH2Cl2 to give 1.87 g (31%) of the imidazole 5 as a pink oil. A solution of 5 (0.55 g, 2.48 mmol) in acetone (20 ml) containing HCl (5 N, 0.5 ml) was stirred for 5 h. The reaction was concentrated under reduced pressure, the residues were taken up in H2O, neutralized to pH 7 with saturated aqueous NaHCO3 and extracted exhaustively with CHCl3/isopropyl alcohol (3:1). The combined organic portions were washed consecutively with H2O and brine, dried (MgSO4) and concentrated. Chromatography on SiO2 with 5-10% MeOH (saturated with NH3): CH2Cl2 gave 0.43 g (97%) of the desired ketone 6. A solution of 6 (0.20 g, 1.11 mmol) in anhydrous DMF (4 ml) under argon was treated with triethylamine (0.14 g, 1.33 mmol) and dimethylsulfamoyl chloride (0.19 g, 1.33 mmol) under argon and stirred 16 h. The solids were filtered off and the filtrate was concentrated at via kugelrohr at 100° C. and 0.5 torr. The residues were taken up in CHCl3 and washed consecutively with H2O and brine, dried (MgSO4) and concentrated. Chromatography on SiO2 with 1-5% MeOH:CH2Cl2 gave 0.22 g (69%) of the desired protected imidazole 7 as a mixture of regioisomers which were carried on without separation. A solution of 7 (0.18 g, 0.62 mmol) in anhydrous THF (10 ml) under argon was treated with methylmagnesium chloride (0.32 ml, 3.0 M in THF) and the resulting mixture was stirred 16 h. The reaction was quenched with a small amount of MeOH, concentrated under reduced pressure and the residues were taken up in H2O. The mixture was acidified by the dropwise addition of 1 N HCl until the solution was homogenious and then the pH was adjusted to 7 with saturated aqueous NaHCO3. The organic materials were extacted into CHCl3 and the combined organic portions were washed consecutively with H2O and brine, dried (MgSO4) and concentrated. Chromatography on SiO2 with 5% MeOH:CH2Cl2 gave 0.18 g (95%) of the alcohol 8 as a mixture of regioisomers which were carried on without separation. A solution of 8 (0.14 g, 0.46 mmol) in anhydrous benzene (3 ml) at 0° C. under argon was treated with (methoxycarbonylsulfamoyl) triethylammonium hydroxide, inner salt (Burgess reagent) (0.12 g, 0.51 mmol) and stirred 1 h at 20° C. The reaction was concentrated under reduced pressure and subsequent purification by chromatography on SiO2 with 5% MeOH:CH2Cl2 gave 0.12 g (92%) of the alkenes 9 and 10 as a mixture of isomers which were carried on without separation. The mixture of isomers 9 and 10 (0.12 g, 0.42 mmol) were refluxed in a solution composed of MeOH (2 ml) and KOH (2 ml of a 5 N solution) for 30 h. The reaction was concentrated under reduced pressure and the residues were taken up in H2O and extracted exhaustively with CHCl3. The combined organic portions were washed consecutively with H2O and brine, dried (MgSO4) and concentrated. Chromatography on SiO2 with 5-10% MeOH (saturated with NH3): CH2Cl2 gave 0.05 g (67%) of alkenes 11 and 12 as a mixture of isomers which were carried on without separation.

1. filtrationThe solids were filtered off
2. concentrationthe filtrate was concentrated at via kugelrohr at 100° C.
3. washwashed consecutively with H2O and brine
4. dry with materialdried (MgSO4)
5. concentrationconcentrated
6. customChromatography on SiO2 with 1-5% MeOH:CH2Cl2 gave 0.22 g (69%) of the
7. additionas a mixture of regioisomers which
8. customwere carried on without separation
9. stirringthe resulting mixture was stirred 16 h
10. customThe reaction was quenched with a small amount of MeOH
11. concentrationconcentrated under reduced pressure
12. additionThe mixture was acidified by the dropwise addition of 1 N HCl until the solution
13. washthe combined organic portions were washed consecutively with H2O and brine
14. dry with materialdried (MgSO4)
15. concentrationconcentrated