Hydrochloric Acid → (3S,4R,5S,6R)-3-Amino-6-(hydroxymethyl)tetrahydro-2H-pyran-2,4,5-triol hydrochloride

Temperature

45 °C

The crude mixture of N-benzyl-2-amino-2-deoxy-D-mannose and N-benzyl-2-amino-2-deoxy-D-glucose obtained according to example 2A was suspended in methanol (20-100 mL), and the pH was adjusted to approximately 1-2 with HCl (10-40 mL 2M HCl and additional 2-8 mL conc. HCl). 10% Pd on charcoal (0.4-1.6 g) was added and the reaction mixture was stirred at r.t. or at 45° C. under H2-atmosphere (up to 5 bar) until all the starting material was consumed. The reaction mixture was filtered through Celite® and washed with 20-50 mL of methanol:water (2:1). The solvents were evaporated until approx. 20-40 mL of volume remained. The crystallization of glucosamine hydrochloride was initiated by adding methanol (40-80 mL) to the aqueous sugar solution and kept at 0-5° C. for overnight. The crystals were separated by filtration and washed with cold methanol. Methanol from the mother liquor was evaporated, and to the remaining aqueous solution 20-80 mL isopropanol was added. The solution was kept at 0-5° C. overnight, the crystals formed were filtered, washed with cold isopropanol and dried: 3.9 g of D-mannosamine hydrochloride was isolated.

1. customobtained
2. customwas consumed
3. filtrationThe reaction mixture was filtered through Celite®
4. washwashed with 20-50 mL of methanol:water (2:1)
5. customThe solvents were evaporated until approx. 20-40 mL of volume
6. customThe crystallization of glucosamine hydrochloride
7. additionby adding methanol (40-80 mL) to the aqueous sugar solution
8. customThe crystals were separated by filtration
9. washwashed with cold methanol
10. customMethanol from the mother liquor was evaporated
11. additionto the remaining aqueous solution 20-80 mL isopropanol was added
12. waitThe solution was kept at 0-5° C. overnight
13. customthe crystals formed
14. filtrationwere filtered
15. washwashed with cold isopropanol
16. customdried

ORD record

ord-6ad1ad3fdd034b2cbbcc9b42d5ec729a

Source dataset

uspto-grants-2015_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09187513B2