Determination of Relative Stereochemistry of an Unknown Carbohydrate: Application of Two-dimensional NMR and the Karplus Relationship

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 16 (2011) pp 304-306

Determination of Relative Stereochemistry of an Unknown Carbohydrate: Application of Two-dimensional NMR and the Karplus Relationship

Jonathan S. Rhoad

Department of Chemistry, Missouri Western State University, 4525 Downs Drive, St. Joseph, MO 64507, jrhoad1@missouriwestern.edu
Received July 5, 2011. Accepted September 19, 2011.

Published: 21 November 2011

Abstract. An experiment designed for the second semester organic chemistry course is described. An unknown carbohydrate is derivatized and recrystallized to give a single diastereomer. The absolute assignment of all hydrogen peaks can be made based on the correlation spectroscopy (COSY) spectrum, and the relative stereochemistry can be assigned based on the ³J_HH coupling constants according to the Karplus relationship.

Key Words: Laboratories and Demonstrations; organic chemistry; nuclear magnetic resonance; pyranoside stereochemistry

(*) Corresponding author. (E-mail: jrhoad1@missouriwestern.edu)

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Supporting Materials:

The 1D ¹H and ¹³C spectra for the derivatives are included (222 KB)