Methanol → 2,4-Bis-(N-(Cbz-valinyl)amino)-1,5-diphenyl-3-pentyl alpha-bromoacetate

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Reaction Steps

The resultant compound of Example 70 (600 mg, 0.81 mmol) was dissolved in 8 mL of methylene chloride and 72 μL (0.9 mmol) of pyridine. The solution was cooled in an ice bath with stirring under a nitrogen atmosphere. α-Bromoacetyl bromide (181 mg, 0.9 mmol) was added in one portion and the ice bath was removed. The reaction mixture was stirred at ambient temperature for 3 h and then diluted with 150 mL of chloroform. The chloroform solution was washed with 150 mL of water, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue (644 mg) was taken up in a mixture of chloroform and methanol and adsorbed onto approximately 1.5 g of 40 mesh silica gel in vacuo @ 40° C. The silica gel with the product adsorbed onto it was applied to a 1.0×40 cm column of 40 mesh silica gel and the column was eluted @ ~5 p.s.i. sequentially with 100 mL of chloroform and 100 mL of 1% methanol in chloroform to give 378 mg (55% yield) of the title compound; FAB MS M/Z: 859 (M+H)+. The 300 MHz 1H NMR spectrum was consistent with the assigned structure.

Provenance & Evidence