434286-39-2

Upstream product

• 1078691-95-8 (+)-D-glucosamine hydrochloride 
• 791790-05-1 phenyl 4,6-O-(p-methoxybenzylidene)-2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside 
• 79528-49-7 phenyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside 
• 136882-36-5 2-((2S,3R,4R,5S,6R)-4,5-Dihydroxy-6-hydroxymethyl-2-phenylsulfanyl-tetrahydro-pyran-3-yl)-isoindole-1,3-dione 
• 10022-13-6 1,3,4,6-tetra-O-acetyl-2-deoxy-2-phthalimido-D-glucopyranose 
• 31505-45-0 2-deoxy-2-phthalimido-D-glucopyranose 
• 85-44-9 phthalic anhydride 
• 791790-08-4 phenyl 3-O-(tert-butyldimethylsilyl)-4,6-O-(p-methoxybenzylidene)-2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside 

Relevant academic research and scientific papers

Temperature-controlled regioselectivity in the reductive cleavage of p-methoxybenzylidene acetals

The regioselective ring opening of pyranosidic 4,6-p-methoxybenzylidene acetals with BH3/Bu2BOTf in THF can be tuned by adjusting the reaction temperature and reagent concentrations. Reductive cleavage at 0 °C resulted in the exclusive formation of 4-O-p-methoxybenzyl (PMB) ethers, whereas reaction at -78 °C produced 6-O-PMB ethers in high yields. The latter condition was observed to be compatible with a variety of acid-sensitive functional groups, including allyl and enol ethers. The presence of water does not interfere with reductive ring opening and may contribute toward in situ generation of H+ as a catalyst for 6-O-PMB ether formation. Reductive cleavage under rigorously aprotic conditions is greatly decelerated, and yields only the 4-O-PMB ether. The temperature-dependent reductive cleavage of the 4,6-acetal can be described in terms of kinetic versus thermodynamic control: Lewis-acid coordination of the more accessible O-6 is favored at higher temperatures, whereas protonation of the more basic but sterically encumbered O-4 predominates at low temperatures.

Optimized synthesis of an orthogonally protected glucosamine

Glucosamine hydrochloride was transformed into an orthogonally protected intermediate in seven steps and 34% overall yield. The synthesis includes an optimized preparation of N-phthaloyl-β-D-glucosamine tetraacetate, a commonly used precursor in carbohydrate chemistry.