1-Hydroxybenzotriazole → Tert-Butyl 6-{[2-cyclopentyl-2-{4-[(5-oxo-2-phenyl-5,6-dihydro-4H-1,3,4-oxadiazin-4-yl)-methyl]phenyl}acetyl]amino}heptanoate

Participants

Reaction Conditions

Reaction Steps

At RT, 41.3 mg (0.306 mmol) of HOBt and 126 μl (0.764 mmol) of DIEA were added to a solution of 100 mg (0.255 mmol) of (+)-cyclopentyl{4-[(5-oxo-2-phenyl-5,6-dihydro-4H-1,3,4-oxadiazin-4-yl)methyl]phenyl}acetic acid and 76.9 mg (0.382 mmol) of tert-butyl(+/−)-6-aminoheptanoate in 0.3 ml of DMF. The resulting mixture was cooled to 0° C., after which 116.3 mg (0.306 mmol) of HATU were added. The reaction mixture was slowly warmed to RT, stirred at RT for 1 h and then diluted with ethyl acetate. The organic phase was washed with saturated sodium bicarbonate solution and with saturated sodium chloride solution, dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by preparative RP-HPLC (acetonitrile/water gradient). This gave 118 mg (about 83% pure, about 67% of theory) of the target compound as a diastereomer mixture.

Provenance & Evidence