87251-89-6

Upstream product

• 50-99-7 D-glucose 
• 60-18-4 L-tyrosine 
• 492-61-5 β-D-glucose 
• 32786-02-0 2,3:4,5-bis-O-(isopropylidene)-D-fructopyranose aldehyde 
• 173966-40-0 (S)-3-(4-Hydroxy-phenyl)-2-[((3aS,5aR,8aR,8bS)-2,2,7,7-tetramethyl-tetrahydro-bis[1,3]dioxolo[4,5-b;4',5'-d]pyran-3a-ylmethyl)-amino]-propionic acid 

Relevant academic research and scientific papers

An unusual decarboxylative maillard reaction between L-DOPA and D-glucose under biomimetic conditions: Factors governing competition with Pictet-Spengler condensation

In 0.1 M phosphate buffer at pH 7.4 and 37°C, the tyrosine metabolite L-3,4-dihydroxyphenylalanine (L-DOPA) reacts smoothly with D-glucose to afford, besides diastereoisomeric tetrahydroisoquinolines 1 and 2 by Pictet-Spengler condensation, a main product shown to be the unexpected decarboxylated Amadori compound N-(1-deoxy-D-fructos-1-yl)-dopamine (3). Under similar conditions, dopamine gave only tetrahydroisoquinoline products 4 and 5, whereas L-tyrosine gave exclusively the typical Amadori compound 6. Fe3+ and Cu2+ ions, which accumulate in relatively high levels in parkinsonian substantia nigra, both inhibited the formation of 3. Cu2+ ions also inhibited the formation of 1 and 2 to a similar degree, whereas Fe3+ ions increased the yields of 1 and 2. Apparently, the formation of 3 would not be compatible with a simple decarboxylation of the initial Schiff base adduct, but would rather involve the decarboxylative decomposition of a putative oxazolidine-5-one intermediate assisted by the catechol ring. These results report the first decarboxylative Maillard reaction between an amino acid and a carbohydrate under biomimetic conditions and highlight the critical role of transition metal ions in the competition with Pictet-Spengler condensation.

Synthesis and 13C NMR investigation of novel Amadori compounds (1-amino-1-deoxy-D-fructose derivatives) related to the opioid peptide, leucine-enkephalin

The N-(1-deoxy-D-fructos-1-yl) derivatives (Amadori compounds) of the endogenous opioid pentapeptide, leucine-enkephalin (11), leucine-enkephalin methyl ester (12) and of structurally related peptides (9, 10) are synthesized. The equilibrium compositions of the prepared Amadori compounds 9-12 in D 2O and [2H6]DMSO are determined using 13C NMR spectroscopy. In water, the β-pyranose, α-furanose and β-furanose forms are detected, the β-pyranose tautomer being the most abundant at equilibrium (67-75%). The α-pyranose form and open-chain keto form are not detected. In dimethyl sulfoxide, the equilibrium compositions of 9-12 are markedly shifted towards a higher proportion of furanose forms, amounting to two-thirds of the mixture. In addition to the α- and β-furanoses and β-pyranose tautomers, DMSO solutions of compounds 9-12 contain at equilibrium a relatively high proportion of the acyclic hydrate (gem-diol) form (ca. 10%).