197853-41-1Relevant articles and documents
Synthesis of Glucuronoxylan Hexasaccharides by Preactivation-Based Glycosylations
B?hm, Maximilian,Madsen, Robert,Underlin, Emilie N.,d'Errico, Clotilde
supporting information, (2020/05/16)
The synthesis of two glucuronoxylans is described, which both consist of a pentaxylan backbone and a glucuronic acid linked to the 2 position in the fourth xylose residue from the reducing end. The two target molecules differ in the 4 position of the glucuronic acid where one is unsubstituted while the other contains a methyl ether. The pentaxylan backbone is assembled in four glycosylation reactions with phenyl thioglycoside donors. The couplings are performed by preactivation of the donor with in-situ-generated p-nitrobenzenesulfenyl triflate prior to addition of the acceptor. The glucuronic acids are then attached by Koenigs-Knorr glycosylations followed by deprotections. The syntheses employ a total of 8 steps from monosaccharide building blocks and afford the two glucuronoxylans in 12 and 15 % overall yield. The hexasaccharide products are valuable substrates for investigating the activity and specificity of glucuronoxylan-degrading enzymes.
Contribution of phosphates and adenine to the potency of adenophostins at the IP3 receptor: Synthesis of all possible bisphosphates of adenophostin A
Sureshan, Kana M.,Riley, Andrew M.,Thomas, Mark P.,Tovey, Stephen C.,Taylor, Colin W.,Potter, Barry V. L.
supporting information; experimental part, p. 1706 - 1720 (2012/05/04)
Although adenophostin A (AdA), the most potent agonist of d-myo-inositol 1,4,5-trisphosphate receptors (IP3R), is thought to mimic IP 3, the relative roles of the different phosphate groups and the adenosine motif have not been established. We synthesized all three possible bisphosphate analogues of AdA and glucose 3,4-bisphosphate (7, AdA lacking the 2′-AMP). 2′-Dephospho-AdA (6) was prepared via a novel regioselective dephosphorylation strategy. Assessment of the abilities of these bisphosphates to stimulate intracellular Ca2+ release using recombinant rat type 1 IP3R (IP3R1) revealed that 6, a mimic of Ins(4,5)P2, is only 4-fold less potent than IP3, while 7 is some 400-fold weaker and even 3′3-dephospho-AdA (5) is measurably active, despite missing one of the vicinal bisphosphate groups normally thought to be crucial for IP3-like activity. Compound 6 is the most potent bisphosphate yet discovered with activity at IP3R. Thus, adenosine has a direct role independent of the 2′-phosphate group in contributing toward the potency of adenophostins, the vicinal bisphosphate motif is not essential for activity at the IP3R, as always thought, and it is possible to design potent agonists with just two of the three phosphates. A model with a possible adenine-R504 interaction supports the activity of 5 and 6 and also allows a reappraisal of the unexpected activity previously reported for the AdA regioisomer 2′3-phospho-3′3- dephospho-AdA 40.
Influence of the 4,6-O-benzylidene, 4,6-O-phenylboronate, and 4,6-O-polystyrylboronate protecting groups on the stereochemical outcome of thioglycoside-based glycosylations mediated by 1-benzenesulfinyl piperidine/triflic anhydride and N-iodosuccinimide/t
Crich, David,De la Mora, Marco,Vinod
, p. 8142 - 8148 (2007/10/03)
The effect of 4,6-O-benzylidene acetals, 4,6-O-phenylboronate esters, and 4,6-O-polystyrylboronate esters on the stereoselectivity of couplings to galacto-, gluco-, and mannopyranosyl thioglycosides, otherwise protected with benzyl ethers, has been invest
