Diisopropylethylamine → Ethyl 6-{[2-cyclopentyl-2-{4-[(5-oxo-2-phenyl-5,6-dihydro-4H-1,3,4-oxadiazin-4-yl)methyl]-phenyl}acetyl]amino}-2-methylhexanoate

Participants

Reaction Conditions

Reaction Steps

At RT, 72 μl (0.415 mmol) of DIEA were added to a solution of 148 mg (0.377 mmol) of (+)-cyclopentyl{4-[(5-oxo-2-phenyl-5,6-dihydro-4H-1,3,4-oxadiazin-4-yl)methyl]phenyl}acetic acid and 98 mg (about 0.66 mmol, crude material) of ethyl 6-amino-2-methylhexanoate in 1.0 ml of DMF. The resulting mixture was cooled to 0° C., and four portions of altogether 186.4 mg (0.49 mmol) of HATU were then added. The reaction mixture was slowly warmed to RT, stirred at RT for 16 h and then added to water and extracted three times with ethyl acetate. The combined organic phases were dried over sodium sulfate and concentrated under reduced pressure. Purification of the residue by preparative RP-HPLC (acetonitrile/water gradient) gave 134.0 mg (64.9% of theory) of the target compound as a diastereomer mixture.

Provenance & Evidence