反应详情

To a solution of t-butyl 4-aminobenzoate (2.0 g, 10.3 mmol) in CH2Cl2 (20 mL) was added 1,3-bis(benzyloxycarbonyl)-2-methyl-2-thiopseudourea (5.6 g, 15.5 mmol), Et3N (5.0 mL, 36 mmol), and mercuric chloride (3.37 g, 12.4 mmol). The reaction mixture was stirred overnight at room temperature. The reaction mixture was filtered through Celite®, and the filtrates were concentrated in vacuo and purified by column chromatography (1:1 CH2Cl2/hexanes to 100% CH2Cl2, and then 10% EtOAc/CH2Cl2) to provide tert-butyl 4-(2,3-bis(benzyloxycarbonyl)guanidino)benzoate (3.9 g, 75%). To a pressure bottle was charged 20% palladium hydroxide on carbon (2 g) followed by a solution of t-butyl 4-(2,3bis(benzyloxycarbonyl)guanidine)benzoate (3.9 g, 7.7 mmol) in EtOAc (80 mL). The mixture was stirred under hydrogen at 50 psi at room temperature overnight. The solution was filtered through Celite® and the filtrate evaporated in vacuo to provide t-butyl guanidinobenzoate (1.8 g, 100%). To the guanidine (855 mg, 3.6 mmol) in EtOAc (50 mL) was add 2M HCl in Et2O (1.9 mL, 3.8 mM). The solution was concentrated and the precipitate was collected by filtration, washed with Et2O and dried in vacuo to yield (840 mg, 85%) of the HCl salt.

1. filtrationThe reaction mixture was filtered through Celite®
2. concentrationthe filtrates were concentrated in vacuo
3. custompurified by column chromatography (1:1 CH2Cl2/hexanes to 100% CH2Cl2