Acetic Anhydride → 3-(S)-t-butyloxycarbonylamino-1-t-butyloxycarbonylmethyl-5-acetoxy-2,3,4,5-tetrahydro-1H-[1]benzazepin-2-one

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Reaction Steps

A solution of 3-(S)-t-butyloxycarbonylamino-1-t-butyloxycarbonylmethyl-5-hydroxy-2,3,4,5-tetrahydro-1H-[1]benzazepin-2-one (described above, 3.0 g) in acetic anhydride (50 ml) was heated at 80° under a dry nitrogen atmosphere for 2 hours. The acetic anhydride was evaporated. The residue was dissolved in ethyl acetate (75 ml) and washed with saturated sodium bicarbonate (50 ml), water (50 ml), and saturated sodium chloride (50 ml). The organic phase was dried (sodium sulfate), evaporated, and the residue triturated with ether (50 ml) to give 3-(S)-t-butyloxycarbonylamino-1-t-butyloxycarbonylmethyl-5-acetoxy-2,3,4,5-tetrahydro-1H-[1]benzazepin-2-one, m.p. 164°-166.5° C., [α]D =-169° (c=0.36 in DMF).

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