.beta.-D-Glucofuranose, pentapropanoate synthesis

Yield:-

Reaction Conditions:

with boric acid

Steps:

1 1,2,3,5,6-Penta-O-propanoyl-β-D-glucofuranose

Example 1 1,2,3,5,6-Penta-O-propanoyl-β-D-glucofuranose D-Glucose (5.0 g, 27.8 mmol), boric acid (3.5 g, 56.9 mmol, 2.05 eq.) and propanoic acid (75 mL) were stirred at 70° C. for one hour. By this time, all the D-glucose had dissolved. Propanoic anhydride (75 mL) was added slowly and the resulting mixture was heated at 70° C. for 48 hours. The reaction mixture was diluted to 1000 mL with ice (100 g) and water and the mixture stirred vigorously for one hour. The resulting precipitate was collected by filtration and recrystallized twice from ethanol (20 mL) to give the title compound as white prisms (7.4 g, 58%); mp 74.5-75.5° C., [α]_D²²-30.8 (c 5.0, CHCl₃). IR (CDCl₃) 2987, 1740 cm^-1. ¹H NMR (CDCl₃): δ 6.14 (s, 1H, H1), 5.42 (d, 1H, J=4.8 Hz, H3), 5.29 (ddd, 1H, J=9.4, 5.2, 2.5, Hz, H5), 5.10 (s, 1H, H2), 4.63 (dd, 1H, J=12.3, 2.5 Hz, H6a), 4.55 (dd, 1H, J=9.4, 4.7 Hz, H4), 4.10 (dd, 1H, J=12.3, 5.2 Hz, H6b), 2.40 (q, 2H, J=7.6 Hz), 2.38 (q, 2H, J=7.6 Hz), 2.37 (q, 2H, J=7.6 Hz), 2.34 (q, 2H, J=7.6 Hz), 2.26 (q, 2H, J=7.6 Hz) (5*CH₂), 1.17 (t, 6H, J=7.6 Hz), 1.13 (t, 6H, J=7.6 Hz), 1.09 (t, 3H, J=7.6 Hz) (5*CH₃) ppm. ¹³C NMR (CDCl₃): δ 174.3, 173.4, 173.0, 172.9 (2) (5*C=O), 99.2 (C1), 80.2 (C4), 79.9 (C2), 73.2 (C3), 68.6 (C5), 63.3 (C6), 28.0, 27.7 (3), 27.6 (5*CH₂), 9.4, 9.2 (2), 9.1 (2) (5*CH₃) ppm. LRMS (FAB) 387 (M⁺-C₃H₅O₂, 100%), 183 (24), 137 (25), 57 (52) m/z. HRMS (FAB): calcd for C₂₁H₃₂O₁₁ (M⁺-H) 459.186360, found 459.186637. Anal: calcd for C₂₁H₃₂O₁₁: C 54.78; H 7.00. Found: C 54.80; H 6.96. The perpropanoylated glucofuranose of Example 1 was obtained in crystalline form and in greater than approximately 90% anomeric purity. The compound is therefore desirable is a starting material for the synthesis of other compounds containing chiral carbon atoms.

References:

US6620921,2003,B1