DL-[3', 5'-13C2]Tyrosine (91% 13C enriched) was synthesized by a ten-step synthetic scheme in an overall yield of 22% (86+% per step) using [l, 3-13C2]acetone as the source of label. The enantiomers were resolved by enzymatic methods, and the labeled DL amino acid or purified enantiomers readily converted to the Nα-Boc acids suitable for peptide synthesis. BOC-DL-[3', 5'-13C2]tyrosine was used for the total synthesis of the specifically labeled peptide hormone derivatives [2-DL-[3',5'-13C2]tyrosine]oxytocin and [2-DL-[3',5,-13C2]tyrosine, 8-arginine]vasopressin by solid phase methods. The diastereoisomers were separated from each other by partition chromatography on Sephadex G-25 followed by gel filtration to give the following specifically labeled hormone derivatives : [2-[3',5'-l3C2]tyrosine]oxytocin, [2-D-[3',5'-13C2]tyrosine]oxytocin, [2-[3',5'-13C2]tyrosine, 8-arginine]vasopressin, and [2-D-[3', 5'-13C2]tyrosine, 8-arginine]vasopressin. The milk ejecting activities were determined.
ASJC Scopus subject areas
- Organic Chemistry