THE AMINO ALCOHOL PROLINOL: A ROTATIONAL STUDY

Alonso, Elena R.

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https://hdl.handle.net/2142/107383 Copy

Description

Title

THE AMINO ALCOHOL PROLINOL: A ROTATIONAL STUDY

Author(s)

Alonso, Elena R.

Contributor(s)

Cocinero, Emilio J.; Calabrese, Camilla ; Insausti, Aran

Issue Date

23-Jun-20

Keyword(s)

Structure determination

Abstract

\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.8]{abstractprolinol.eps} \end{wrapfigure} The amino alcohol prolinol is a reduction product of the chiral amino acid proline, which is widely used as a chiral auxiliary in noted reactions. Up to date, only IR data for prolinol is available.\footnote{J.J. Lee, S. Hesse, M.A. Suhm. \textit{Journal of Molecular Structure}, \textbf{2010}, \underline{976}, 397–404} Here, we report the first high-resolution microwave study of this system. Two endo-like and exo-like conformations stabilized by strong intramolecular hydrogen bonds O-H···N have been detected in the supersonic expansion of our CP-FTMW technique.\footnote{I. Uriarte, C. P\'{e}rez, E. Caballero-Mancebo, F. J. Basterretxea, A. Lesarri, J. A. Fern\'{a}ndez and E. J. Cocinero, \textit{Chem. - A Eur. J.}, \textbf{2017}, \underline{23}, 7156}$^{,}$\footnote{C. Calabrese, W. Li, G. Prampolini, L. Evangelisti, I. Uriarte, I. Cacelli, S. Melandri,and E. J. Cocinero, \textit{Angew.Chem.}, \textbf{2019}, \underline{131},8525–8530} These structures have been successfully identified by comparison of the experimental rotational and $^{14}$N nuclear quadrupole coupling constants with those predicted theoretically. Given the high sensitivity reached in our experiment, the seven monosubstituted species of $^{13}$C, $^{15}$N and $^{18}$O have also been observed in their natural abundance for both conformers, and the corresponding r$_{s}$ substitution structure has been derived. The monohydrate of the most abundant endo form has also been detected. The water interacts simultaneously, acting as a proton donor to the imine nitrogen atom and accepting a proton from the hydroxyl group. This configuration benefits from two intermolecular hydrogen bonds, OH···O and O-H···N, closing a six-membered ring configuration. These first results pave the way for future studies on the chiral recognition of prolinol.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

English

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