Sparteine → 3-[(2R,3S)-2-{[(4S)-4-benzyl-2-oxo-1,3-thiazolidin-3-yl]carbonyl}-5-(3',5'-difluorobiphenyl-4-yl)-3-hydroxypentyl]-1,2,3-benzotriazin-4(3H)-one

Participants

Reaction Conditions

Reaction Steps

In a flame-dried flask, 3-{3-[(4S)-4-benzyl-2-oxo-1,3-thiazolidin-3-yl]-3-oxopropyl}-1,2,3-benzotriazin-4(3H)-one (0.25 g) was taken up in dichloromethane (10 mL) and cooled to 0° C. Titanium tetrachloride (0.76 mL, 1 M solution) was added drop-wise and the reaction mixture was stirred for 10 to 15 minutes. (−)-Sparteine (0.36 mL) was added slowly to the reaction mixture and stirred at 0° C. for 20 minutes. A solution of the compound obtained from step e above (0.187 g) in dichloromethane (10 mL) was added slowly and stirring was continued at 0° C. After 3 hours, the reaction was quenched with the drop-wise addition of saturated ammonium chloride solution, and dichloromethane was added. The organic layer was separated and the aqueous layer was extracted with dichloromethane. The organic layer was washed with brine, dried over anhydrous sodium sulphate, and concentrated under reduced pressure. The crude product thus obtained was purified by silica gel flash column chromatography using 30% ethyl acetate in hexane as eluant to afford the title compound (0.24 g).

Provenance & Evidence