tert-butyl 2-(3-(3-cyanophenethoxy)-N-cyclohexylpropanamido)ethyl(2-(5-hydroxy-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-8-yl)ethyl)carbamate → tert-Butyl 2-(N-cyclohexyl-3-(3-formylphenethoxy)propanamido)ethyl(2-(5-hydroxy-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-8-yl)ethyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of tert-butyl 2-(3-(3-cyanophenethoxy)-N-cyclohexylpropanamido)ethyl(2-(5-hydroxy-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-8-yl)ethyl)carbamate [Examples 81-175, step e] (7.3 g) in pyridine (115 mL), acetic acid (58 mL) and water (58 mL), pre-cooled in ice-water under nitrogen, was added sodium hypophosphite monohydrate (14.6 g) followed by Raney® nickel (50% in water, 3.0 g). The reaction mixture was stirred at 45° C. for 8 hours, then allowed to cool and stand over a weekend. Celite was added and the suspension was filtered through a pad of Celite, washing the residue well with acetic acid and ethyl acetate. The filtrate was washed three times with water, once with brine, then dried (MgSO4), filtered and concentrated in-vacuo. The residue was azeotroped twice with toluene to afford the subtitled compound as a pale yellow foam. Yield 6.6 g.

Provenance & Evidence