B 3607 (OTTO) (3R)-N-(tert-Butoxycarbonyl)-3-amino-4-(2,4,5-trifluorophenyl)butanoic acid, 98% Cas 486460-00-8 - used as a reactant for the preparation of dipeptidyl peptidase-4 (DPP4) inhibitors for the treatment of type 2 diabetes, such as sitagliptin.