Diisopropylethylamine → 2-(trimethylsilyl)ethyl (S)-2-(3-benzoylcyclohexanecarboxamido)-3-cyclohexylpropylmethylcarbamate

Participants

Reaction Steps

To a stirred solution of cis-3-benzoylcyclohexane-1-carboxylic acid (78 mg, 0.34 mmol), 2-(trimethylsilyl)ethyl (S)-2-amino-3-cyclohexylpropylcarbamate (116 mg, 0.37 mmol) and diisopropylethylamine (0.13 mL, 0.70 mmol) in CH2Cl2 (2 mL) were added solid 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU, 200 mg, 0.53 mmol) and DMF (0.5 mL). The mixture was stirred at rt for 3 h, diluted with ether (90 mL), washed with 5% aqueous HCl (25 mL), sat'd aqueous NaHCO3 (25 mL), and brine (25 mL) and dried over Na2SO4. Removal of the solvent under reduced pressure left an oil (260 mg) which was applied to a 2-g silica SPE cartridge and eluted sequentially with 0, 10, 25, 50, 75, and 100% EtOAc in hexanes (15 mL of each) to give six fractions. Fractions 2-4 were pooled and evaporated to afford 2-(trimethylsilyl)ethyl (S)-2-(3-benzoylcyclohexane-carboxamido)-3-cyclohexylpropylmethylcarbamate (170 mg, 91%) as an oil. MS ESI +ve m/z 528 (M+1).

Provenance & Evidence