Carbamic acid,N-[(1S)-1-[(3S)-8-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2,3-dihydro-2-oxo-3-[2-oxo-2-[(phenylmethyl)amino]ethyl]-1H-1,4-benzodiazepin-5-yl]ethyl]-, 1,1-dimethylethyl ester