Acetic Acid → HCID 52935018, compound

Participants

Reaction Steps

A suspension of 1-methylethyl[(2S,4R)-1-acetyl-6-(4-formylphenyl)-2-methyl-1,2,3,4-tetrahydro-4-quinolinyl]carbamate (for a preparation see Intermediate 68) (1.078 g, 2.73 mmol) in dichloromethane (DCM) (20 mL) under nitrogen was treated with acetic acid (0.313 mL, 5.47 mmol) and piperidine (0.279 g, 3.28 mmol). The resulting mixture was stirred at room temperature for 1 h then sodium triacetoxyborohydride (0.695 g, 3.28 mmol) was added and the reaction left to stir at room temperature over 60 h then concentrated in vacuovacuo. The residue was partitioned between a saturated NaHCO3 aqueous solution (25 mL) and AcOEt (40 mL) and the layers were separated. The aqueous phase was extracted with AcOEt (25 mL) and the combined organic phases were washed with brine, dried over Na2SO4 and concentrated in vacuovacuo. The residue was loaded on a 20 g SCX cartridge and eluted with MeOH (45 mL) then with 2M NH3 in MeOH (2×45 mL). The ammonia fractions were combined and concentrated in vacuo to give a first residue. The methanol fractions were concentrated and the residue obtained was loaded on a 20 g SCX cartridge and eluted with MeOH (45 mL) then with 2M NH3 in MeOH (2×45 mL). The ammonia fractions were combined and concentrated in vacuo to give a second residue. The two residues were combined and purified by flash chromatography on silica gel using an SP4 and a 100 G cartridge (gradient:1 to 5% (2M NH3 in MeOH) in DCM) to give 1-methylethyl {(2S,4R)-1-acetyl-2-methyl-6-[4-(1-piperidinylmethyl)phenyl]-1,2,3,4-tetrahydro-4-quinolinyl}carbamate (0.9195 g, 1.884 mmol, 68.9% yield) as a yellow oil.

Provenance & Evidence