185754-29-4

Upstream product

• 2872-72-2 phenyl-2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside 
• 108-95-2 phenol 
• 3068-32-4 1-bromo-1-deoxy-2,3,4,6-tetra-O-acetyl-a-D-galactopyranoside 
• 25878-60-8 D-galactose pentaacetate 
• 2186-92-7 p-Anisaldehyde dimethyl acetal 
• 2818-58-8 phenyl-β-D-galactopyranoside 

Downstream Products

• 461026-31-3 phenyl 2,3-di-O-acetyl-4-methylumbelliferyl-6-O-para-methoxybenzyl-β-D-glucopyranoside 
• 461026-30-2 phenyl 2,3-di-O-acetyl-6-O-para-methoxybenzyl-4-O-trifluoromethanesulfonyl-β-D-galactopyranoside 
• 461026-33-5 phenyl 2,3-di-O-acetyl-4-methylumbelliferyl-β-D-glucopyranosiduronic acid 
• 461026-32-4 phenyl 2,3-di-O-acetyl-4-methylumbelliferyl-β-D-glucopyranoside 
• 461026-34-6 phenyl 4-methylumbelliferyl-β-D-glucopyranosiduronic acid 

Relevant academic research and scientific papers

Elucidation of the mechanism of polysaccharide cleavage by chondroitin AC lyase from Flavobacterium heparinum

Chondroitin AC lyase from Flavobacterium heparinum degrades chondroitin sulfate glycosaminoglycans via an elimination mechanism resulting in disaccharides or oligosaccharides with Δ4,5-unsaturated uronic acid residues at their nonreducing end. Mechanistic details concerning the ordering of the bond-breaking and -forming steps of this enzymatic reaction are nonexistent, mainly due to the inhomogeneous nature of the polymeric substrates. The creation of a new class of synthetic substrates for this enzyme has allowed the measurement of defined and reproducible kcat and Km values and has expanded the range of mechanistic studies that can be performed. The primary deuterium kinetic isotope effect upon kcat/Km for the abstraction of the proton α to the carboxylic acid was measured to be 1.67 ± 0.07, showing that deprotonation occurs in a rate-limiting step. Using substrates with leaving groups of differing reactivity, a flat linear free energy relationship was produced, indicating that the C4-O4 bond is not broken in a rate-determining step. Taken together, these results strongly suggest a stepwise mechanism. Consistent with this was the measurement of a secondary deuterium kinetic isotope effect upon kcat/Km of 1.01 ± 0.03 on a 4-{2H}-substrate, indicating that no sp2 character is developed at C4 during the rate-limiting step, thereby ruling out a concerted syn-elimination.

Asymmetric hydrogenation - Influence of the structure of carbohydrate derived catalysts on the relative enantioselectivity Q(H/Me) regarding acid and ester substrates and its inversion - Selectivity increase in water by amphiphiles

4,6-O-Benzylidene protected 2,3-bis(O-diphenylphosphino)-D-glycopyranoside rhodium(I) chelate precatalysts 1-4 e,f showed for the hydrogenation of methyl (Z)2-N-acylamidoacrylates 6-8 a stepwise decrease of the enantioselectivity with increasing number of axially oriented hexopyranoside substituents. The decrease is even stronger for the analogous substrate acids 6h-8h resulting in an unusual low relative enantioselectivity Q = q(H)/q(Me) of 0.3 for the precatalysts 4e and 4f. Deprotected, 4,6-OH-group bearing catalysts 1-4 g,h generally show smaller differences of %ee in methanol or benzene, however, not in water. Under addition of amphiphiles a in comparison with blanks b the relative enantioselectivity Q = q(a)/q(b) clearly increases for both groups of catalysts in most cases to Q-values between 3 up to 8 - independent of a neutral or ionic nature of the amphiphile.