| Popis: |
The NMR spectrum of N-(benzyloxycarbonyl)-L-proline t-butyl ester shows two t-butyl signals of slowly interconverting syn and anti rotamers. The t-butyl signals have been assigned to the syn and the anti form by using Eu(fod), as a shift reagent. The thermodynamic parameters ΔG≠, ΔH≠ and ΔS≠ for rotation about the amide bond have been determined by the method of Shanan — Atidi and Bar-Eli and by complete line shape analysis, in four solvents of different polarity. The results are discussed. |
