Sodium Hydroxide → tert-butyl ((1S,4S)-4-(2-mercaptoethyl)-4-(3-(trifluoromethyl)-5,6,7,8-tetrahydro-1,6-naphthyridine-6-carbonyl)cyclopent-2-en-1-yl)carbamate

To a solution of the product of Step A (1.74 g, 3.39 mmol, 1 eq) in methanol (100 mL) at rt under Ar (degassed) was added 0.2 N NaOH (85 mL, 85 mmol, 5 eq) that was degassed by bubbling Ar through the solution prior to addition. After 2 hr, the methanol was concentrated, 6 N HCl was added until the solution was acidic, the aqueous was extracted with DCM, the organics combined, dried over MgSO4 and concentrated to afford the product of Step B which was used unpurified in the next step. Calculated for C22H28F3N3O3S: 494.2 (M+23). found: 494.1.