The Structure of N‐(1‐Deoxy‐β‐D‐fructopyranos‐1‐yl)‐L‐proline Monohydrate (“D‐Fructose‐L‐proline”) and N‐(1,6‐Dideoxy‐α‐L‐fructofuranos‐1‐yl)‐L‐proline (“L‐Rhamnulose‐L‐proline”)

Abstract

D-Fructose-L-proline is an important food-related precursor for thermally generated aromas. We report the crystal structure analysis of N-(1-deoxy-b-D-fructopyranos-1-yl)-L-proline monohydrate (1) and its analog, N-(1,6-dideoxy-a-L-fructofuranos-1-yl)-L-proline ("L-rhamnulose-L-proline") (2). The carbohydrate rings adopt the normal 2 C 5 pyranose chair conformation in 1 and the 5 E 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.

Matched/Mismatched Cases in Proline-Catalyzed Cascade Reactions with Carbohydrates: A Computational Insight into the Role of d- and l-Proline

“…The formation of the iminium-intermediate rib - IV is consistent with the well-documented reaction mechanism of the Maillard reaction . However, the classical subsequent Amadori rearrangement, which would have been expected under these reaction conditions, was in fact not observed …”

Development of a Method and Validation for the Quantitation of FruArg in Mice Plasma and Brain Tissue Using UPLC–MS/MS

“…Several amino acids and sugars have the ability to cross the BBB. , The molecular weight of FruArg is 336, and it has 11 heteroatoms theoretically capable of participating in hydrogen bonding. However, the available crystallographic data consistently demonstrated a propensity of 3–4 heteroatoms in FAs to form strong intramolecular hydrogen bonds, whereas the furanose oxygen did not involve in any hydrogen bond formation . We therefore have hypothesized that the low molecular weight and structural characteristics of FruArg may allow it to cross the BBB and enter the brain.…”

“…However, the available crystallographic data consistently demonstrated a propensity of 3–4 heteroatoms in FAs to form strong intramolecular hydrogen bonds, whereas the furanose oxygen did not involve in any hydrogen bond formation. 36 We therefore have hypothesized that the low molecular weight and structural characteristics of FruArg may allow it to cross the BBB and enter the brain.…”