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Synthesis and carbon-13 nuclear magnetic resonance spectra of Cyclo(D-leucyl-L-leucine) and Cyclo(L-leucyl-L-leucine)

✍ Scribed by Mary M. Exner; Robert J. Kostelnik

Publisher
Wiley (John Wiley & Sons)
Year
1977
Tongue
English
Weight
493 KB
Volume
16
Category
Article
ISSN
0006-3525

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✦ Synopsis

Abstract

Cyclo(D‐Leu‐L‐Leu) and cyclo(L‐Leu‐L‐Leu) were synthesized, and their carbon‐13 nmr spectra at 65 MHz were examined in dimethylsulfoxide and trifluoroacetic acid solutions. The chemical shift data are consistent with a boat or “twisted” boat conformation of the diketopiperazine ring in both solvents. There was no indication of protonation of the cyclic dipeptides by trifluoroacetic acid. Attempts at polymerizing the cyclic dipeptides were unsuccessful.

📜 SIMILAR VOLUMES

Influence of D and L amino-acid residues
Influence of D and L amino-acid residues on the conformation of peptides in solution: A carbon-13 nuclear magnetic resonance study of cyclo(prolyl-leucyl)
✍ Roxanne Deslauriers; Z. Grzonka; Roderich Walter 📂 Article 📅 1976 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 375 KB 👁 2 views

## Abstract The ^13^C chemical shifts and spin‐lattice relaxation times are reported for __cyclo__(L‐Pro‐L‐Leu) and __cyclo__(L‐Pro‐D‐Leu). The chemical shifts of the D and L leucyl residues in the cyclic peptides differ from each other by 1.8 and 3.6 parts per million for the α and β carbons, resp