Example 54
To a mixture of 1-methyl-3-{[4-(piperidin-4-yl)phenyl]amino}-5-(1,3-thiazol-2-yl)pyrazin-2-one (24 mg, 0.065 mmol) and 1-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]piperidine-4-carbaldehyde (24 mg, 0.065 mmol) in 1,2-dichloroethane (1.0 mL) was added sodium triacetoxyborohydride (41 mg, 0.20 mmol). After 30 minutes, additional portions of 1-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]piperidine-4-carbaldehyde (24 mg, 0.065 mmol) and sodium triacetoxyborohydride (41 mg, 0.20 mmol) were added. After 30 more minutes, water was added and the mixture was extracted twice with dichloromethane. The combined organic layers were concentrated then purified by preparative TLC eluted with 10% MeOH/DCM to provide 2-(2,6-dioxopiperidin-3-yl)-5-(4-{[4-(4-{[4-methyl-3-oxo-6-(1,3-thiazol-2-yl)pyrazin-2-yl]amino}phenyl)piperidin-1-yl]methyl}piperidin-1-yl)isoindole-1,3-dione (0.017 g, 35%).
