Sodium Sulfate → HCID 68565229, compound

Participants

Reaction Steps

A solution of cis-4-amino-1-tert-butoxycarbonyl-3-fluoropiperidine (5a) (340 mg, 1.60 mmole) in ClCH2CH2Cl (8 mL) and EtOH (0.8 mL) was treated with anhydrous Na2SO4 (450 mg) and 3-oxo-3,4-dihydro-2-benzo[1,4]thiazine-6-carboxaldehyde (1n) (330 mg, 1.80 mmole). The resulting solution was stirred at room temperature for 6 hr, then sodium triacetoxy borohydride (500 mg, 2.40 mmole) was added. The resulting slurry was stirred at room temperature for a further 10 hr, then was quenched by the addition of water (2 mL) and the volatiles were removed in vacuo. The residue was partitioned between EtOAc (2×50 mL) and brine (20 mL). The organic phases were combined, dried (MgSO4), and concentrated in vacuo. The residue was passed through a column of silica gel (100% ethyl acetate), the eluant was concentrated in vacuo and the residue was disolved in 10 mL of CH2Cl2 and treated with 1.25 mL of 4N HCl in dioxane for 2 h. The volitiles were removed in vacuo and the residue was dissolved in 10 mL of CH3OH. MP-carbonate resin (1.08 g) was added and stirred at rt for 1 h. The reaction was filtered to remove the resin and concentration under reduced pressure gave the desired compound as a white solid:

Provenance & Evidence