Diisopropylethylamine → HCID 86746935, compound

Participants

Reaction Steps

Hydroxybenzotriazole 85.7 mg, 0.56 mmol), diisopropylethylamine (90.6 μl, 0.52 mmol) and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (107.3 mg, 0.56 mmol) were sequentially added to a solution of the title D compound (114.2 mg, 0.4 mmol) and compound B from Example 17 (126.2 mg, 0.48 mmol) in 2 ml dimethylformamide at 0°. The reaction mixture was warmed and stirred at room temperature for 60 hours after which it was concentrated, then treated with 15 ml pH=4.01 buffer and extracted with ethyl acetate (3×25 ml). Drying and concentration gave 425 mg crude product which after flash chromatographic purification (20 g silica gel, 19:1 CHCl3 /MeOH) gave 146 mg (74%) of the title compound Isomer A which was characterized by MS, IR, 1H NMR and 13C NMR. After repeated chromatography and finally, crystallization from hexane/ethyl acetate, the title compound Isomer A (56 mg) was obtained, m.p. 165°-170° C. [α]D =-67.1° (c=0.66, CH3OH).

Provenance & Evidence