反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.
实验步骤: A solution of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (4.89 g) in dichloromethane (80 ml) was added to a solution of (±)-1,2,4,5-tetrahydro-7,8-dimethoxy-5-oxo-3-benzothiepin-2-carboxylic acid (6.0 g) and methyl (R)-(+)-lactate (4.43 g) in N,N-dimethylformamide (DMF) (80 ml) at 0° C., followed by the addition of 4-dimethylaminopyridine (DMAP) (1.3 g). This mixture was stirred at 0° C. for 1 hour and at room temperature for 15 hours, and concentrated under reduced pressure. Ethyl acetate (500 ml) and water (500 ml) were added to the residue and then the organic layer was collected. The organic layer was washed with water and dried (MgSO4), after which the solvent was distilled off; the residual solid was collected by filtration and washed with ether, followed by recrystallization twice from ethyl acetate-hexane to yield (R)-1-methoxycarbonylethyl ester of (2R)-(−)-1,2,4,5-tetrahydro-7,8-dimethoxy-5-oxo-3-benzothiepin-2-carboxylic acid (2.2 g, 28%). Colorless needles. Melting point 161-162° C. Optical rotaion [α]D (16° C.) −194.1° (c=0.50, CHCl3). A filtrate of the above-mentioned solid was concentrated and the resulting crystals were collected by filtration with ether-hexane, followed by recrystallization twice from ethyl acetate-hexane to yield (R)-1-methoxycarbonylethyl ester of (2S)-(+)-1,2,4,5-tetrahydro-7,8-dimethoxy-5-oxo-3-benzothiepin-2-carboxylic acid (1.6 g, 20%). Colorless Plates. Melting point 121-122° C. Optical rotaion [α]D (16° C.) +234.3° (c=0.50, CHCl3).
concentrated under reduced pressure
Ethyl acetate (500 ml) and water (500 ml) were added to the residue
the organic layer was collected
The organic layer was washed with water
dried (MgSO4)
after which the solvent was distilled off
the residual solid was collected by filtration
washed with ether
followed by recrystallization twice from ethyl acetate-hexane
来源 ID: ord-c7f10dd902b647989c7f298d77547fef