Ammonium Chloride → 4-Butyl-2-chloro-5-(1-hydroxy-6-methoxycarbonylhexyl)-4-trimethylsilyloxy-2-cyclopentenone

Temperature

-78 °C

54 mg of 4-butyl-4-t-butyldimethylsilyloxy-2-chloro-2-cyclopentenone was dissolved in 2 ml of dry tetrahydrofuran, and the solution was cooled to -78° C. With stirring, a lithium diisopropyl amide solution was added. At -78° C., the mixture was stirred for 30 minutes. A solution of 50 mg of methyl 7-oxoheptanoate in 1 ml of dry tetrahydrofuran was added, and the mixed solution was stirred at -78° C. to -50° C. for 1 hour. A saturated aqueous solution of ammonium chloride was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium chloride, and dried over anhydrous sodium sulfate. After filtration and concentration, the residue was chromatographed on a silica gel column (silica gel 30 g; hexane:ethyl acetate=50:1→10:1) to give 29 mg (yield 33%) of a low polarity isomer of 4-butyl-2-chloro-5-(1-hydroxy-6-methoxycarbonylhexyl)-4-trimethylsilyloxy-2-cyclopentenone and 17 mg (yield 20%) of its high polarity isomer.

1. stirringAt -78° C., the mixture was stirred for 30 minutes
2. stirringthe mixed solution was stirred at -78° C. to -50° C. for 1 hour
3. extractionthe mixture was extracted with ethyl acetate
4. washThe organic layer was washed with a saturated aqueous solution of sodium chloride
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationAfter filtration and concentration
7. customthe residue was chromatographed on a silica gel column (silica gel 30 g; hexane:ethyl acetate=50:1→10:1)

ORD record

ord-df65adf487904ead973e61d3c06b8c6c

Source dataset

uspto-grants-1987_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04711895