Synthesis of 2,5-anhydro-(β-d-glucopyranosyluronate)- and (α-l-idopyranosyluronate)-d-mannitol hexa-O-sulfonate hepta sodium salt

Synthesis and Scalable Conversion of l-Iduronamides to Heparin-Related Di- and Tetrasaccharides

“…This provides a new methodology for the conversion of amides to esters, efficiently illustrated by this synthesis of iduronate acceptor 5 (previously reported as a mixture of anomers) in 60% yield over 2 steps. This mild amide-to-ester chemistry offers considerable synthetic value underpinning the viable exploitation of iduronamide intermediate 2 for the synthesis of a number of iduronic acid derivatives on scale.…”

“…The crude product was purified by flash column chromatography (EtOAc/hexane, 2:1 containing 1% formic acid), yielding 4 (3.14 g, 8.5 mmol, 69%) as an oil: R f 0.06 (EtOAc/hexane 2:1 + 1% HCOOH); [ Methyl 1,2-Di-O-acetyl-3-O-benzyl-β-L-idopyranuronate (5). 21 Method A. To the acid 4 (1.73 g, 4.70 mmol) was added dry DCM (25 mL), and then dimethylformamide dimethylacetal (DMF•DMA) was added dropwise over 40 min (0.7 mL, 4.93 mmol) at 0 °C .…”

Two approaches to the synthesis of 3-β-d-glucopyranosyl-d-glucitol

“…When the reaction was carried out at À40°C, two compounds, the rearranged 6-O-glycoside 8 as well as the orthoester 9 were formed in a 1:2 ratio. The structure of the latter is evident from its NMR spectra as in the 1 signal of the orthoester appears at d 1.76 ppm, well separated from the three acetyl signals (d 2.06, 2.06 and 2.07 ppm), and in the 13 C NMR spectrum the signal of the quaternary carbon atom can be detected at d 121.4 ppm, while the three carbonyl atoms appear at d 168.9, 169.5 and 170.0 ppm, respectively. The NOE effect observed between the methyl group of the orthoester, H-3 0 and H-5 0 proved the exo orientation of the aglycon that is the S-configuration of the orthoester carbon.…”

Crystal Polymorphism of Methyl 2,3,4-tri-O-acetyl-1-O-(trichloroacetimidoyl)-α-d-glucopyranouronate

“…Hence, specific trichloroacetimidates, such as 2,3,4,6-tetra-O-benzyl-1-Otrichloroacetimidoyl-α-D-glucopyranose [10] and methyl 2,3,4-tri-O-acetyl-1-O (trichloroacetimidoyl)-α-D-glucopyranouronate 1 [6], are stable but reactive compounds.…”