The Structure of N-(1-Deoxy-beta-D-fructopyranos-1 -yl)-L-proline Monohydrate ('D-Fructose-L-proline') and N-(l ,6-Dideoxy-a-L-fructof uranos-1 -yl)-L-proline ('L-Rhamnulose-L-proline')

摘要

D-Fructose-L-proline is an important food-related precursor for thermally generated aromas. We report the crystal structure analysis of iV-(l-deoxy-beta-D-fructopyranos-l-yl)-L-proline monohydrate (1) and its analog, N-(l,6-dideoxy-alpha-L-fructofuranos-l-yl)-L-proline ("L-rhamnulose-L-proline") (2). The carbohydrate rings adopt the normal ~2C_5 pyranose chair conformation in 1 and the 5E furanose envelope conformation in 2. Bond lengths and valence angles in 1 and 2 compare well with the average values from related pyranose and furanose structures. All hydroxyl and carboxyl oxygen atoms, ammonium groups, and the water molecule in 1 are involved in an extensive hydrogen bonding, which forms a system of infinite chains with attached side chains. The hydrogen bonding network in 2 is an infinite three-dimensional network and is represented by separate short finite and infinite chains. Keywords Amadori compound, Crystal structure, Fructose-amino acid, D-Fructose-L-proline, Rhamnulose-amino acid, L-Rhamnulose-L-proline