Saxagliptin STD-(1S,3S,5S)-2-[(2S)-2-Amino-2-(3-hydroxytricyclo[3.3.1.13,7]dec-1-yl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carbonitrile: Saxagliptin-IMP-C-(1aS,4S,6aR,7aS)-4-(3-Hydroxyadamantan-1-yl)hexahydro-1H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazine-3,6-dione