Synthesis of a Substituted Benzazepin-2-oneDihydrate

Synthesis of the title compound was accomplished via couplingof ( S)-alaninyl-( S)-1-amino-3-methyl-4,5,6,7-tetrahydro-2 H-3-benzazepin-2-one with the activatedtrimethylsilyl ester of ( S)-2-trimethylsilyloxy-3-methylbutyricacid, followed by deprotection and crystallization in situ. Thestarting material was prepared by the condensation of ( S)-1-amino-3-methyl-4,5,6,7-tetrahydro-2 H-3-benzazepin-2-one with activated N-(2-methoxycarbonyl-1-methylvinyl)-( S)-alanine sodium salt in the form ofthe mixed carboxylic carbonic anhydride, followed by enamine hydrolysisusing methanesulfonic acid.