Beilstein J. Org. Chem. 2012, 8, 1619–1629.
(C-12), 30.0 (C-11), 27.7 (C-9), 25.9 (C-10); anal. calcd for reductive hydrolysis the heptononitriles 18 (4.5 g) were treated
C14H27NO8: C, 49.87; H, 8.09; found: C, 49.79; H, 8.11.
as described employing dist. water (90 mL), acetic acid
(1.35 mL, 1.1 equiv) and Pd/BaSO4 (2.7 g). After TLC (CHCl3/
1-(N-(6-Hydroxyhexyl)amino)-1-N,2-O-carbonyl-1-deoxy-β- MeOH 1:1 v/v containing 0.25% concd NH4OH) showed
D-galacto-hept-2-ulopyranose 26a and -furanose 26b: complete consumption of the starting material, and workup with
General method C was applied to compounds 24a and 24b ion-exchange resin IR-120 H+, 3.7 g of crude aldoheptoses 19a
(349 mg) in H2O (10 mL) and 1,4-dioxane (2 mL), employing and 19b were obtained. NMR analysis of the crude product
Na2CO3 (1.3 g, 11.8 mmol, 6 equiv) and triphosgene (0.6 g, mixture indicated the D-glycero-D-galacto-β-aldoheptose 19a
2.0 mmol, 1.8 equiv). Silica-gel chromatography (CHCl3/ as the predominant compound (4.48 ppm, J1,2 = 7.8 Hz, 1H,
MeOH 3:1 v/v containing 1% of concd NH4OH) gave a mix- H-1β) next to its α-anomer (5.14 ppm, J1,2 = 3.6 Hz, 1H, H-1α)
ture of pyranose 26a and furanose 26b (350 mg, 95%) in a 3:2 in a ratio of 5:2. This compound mixture was used for the
ratio. Pyranose 26a signals: 1H NMR (methanol-d4) δ Amadori rearrangement. General procedure A was applied to
4.07–3.99 (m, 2H, H-5, H-6), 3.87 (d, J1,1 = 10.0 Hz, 1H, H-1), the mixture of aldoheptoses 19 (400 mg) employing EtOH
3.84–3.79 (m, 2H, H-3, H-4), 3.79–3.69 (m, 2H, H-7), 3.58 (t, (5 mL) and 1,4-dioxane (1 mL) as cosovlent, dibenzylamine
2H, H-13), 3.47 (d, 1H, H-1), 3.32–3.25 (m, 2H, H-8), (360 µL, 1.9 mmol) and acetic acid (110 µL, 1.9 mmol). The
1.67–1.49 (m, 4H, H-9, H-12), 1.49–1.30 (m, 4H, H-10, H-11); reaction mixture was stirred at 50 °C for three days. Column
13C NMR δ 158.8 (C=O), 104.6 (C-2), 75.7 (C-5), 71.9, 70.6, chromatography (EE/MeOH 20:1 v/v) gave product 28 in a
70.8 (3C, C-3, C-4, C-6), 62.9 (C-13), 62.4 (C-7), 53.5 (C-1), yield of 72% (540 mg). α-Anomer 28: [α]D = +20 (c 1.1,
44.5 (C-8), 33.5 (C-12), 28.1, 27.4, 26.5 (3C, C-9, C-10, C-11); MeOH); 1H NMR (methanol-d4) δ 7.51–7.24 (m, 10H, Ph),
anal. calcd for C14H25NO8: C, 50.17; H, 7.53; found: C, 50.10; 3.94 (d, J = 13.3 Hz, 2H, CH2Ph), 3.85–3.75 (m, 4H, H-4, H-5,
H, 7.59.
2 × H-7), 3.73–3.60 (m, 3H, H-6, CH2Ph), 3.47 (d, J3,4 = 3.1
Hz, 1H, H-3), 2.93 (d, J1,1 = 13.7 Hz, 1H, H-1), 2.77 (d, 1H,
1-(N-(5-Methoxycarbonylpentyl)amino)-1-N,2-O-carbonyl- H-1); 13C NMR δ 139.8, 130.6, 130.3, 129.6 (Ph), 97.5 (C-2),
1-deoxy-β-D-galacto-hept-2-ulopyranose (27a) and -furanose 75.8, 74.2, 73.3, 68.7 (4C, C-3, C-4, C-5, C-6), 63.2 (C-7), 60.2
(27b): General method C was applied to the mixture of (2C, CH2Ph), 59.9 (C-1); anal. calcd for C21H27NO6: C, 64.77;
Amadori products 26a and 26b (200 mg, 0.6 mmol), Na2CO3 H, 6.43; found: C, 63.07; H, 6.50.
(680.0 mg, 6.4 mmol, 6.0 equiv) and triphosgene (320 mg,
1.1 mmol, 1.8 equiv) in H2O (7 mL) and 1,4-dioxane as 1-(N-(6-Hydroxyhexyl)amino)-1-deoxy-α-D-manno-hept-2-
co-solvent (1 mL). When TLC indicated complete consumption ulose (29): Following general method A, the mixture of aldo-
of the starting material, the solvents were removed under heptoses 19 (360 mg) was treated with 6-aminohexanol
reduced pressure, and silica-gel chromatography (CHCl3/MeOH (200 mg, 1.71 mmol, 1 equiv) in EtOH (5 mL) and 1,4-dioxane
6:1 v/v containing 1% of concd NH4OH) gave a mixture of as co-solvent in the presence of acetic acid (0.1 mL, 1.71 mmol,
cyclic carbamates in the pyranoid 27a and furanoid 27b form in 1 equiv) at 50 °C for three days. When TLC indicated complete
a ratio of 5:3 (280 mg, 50%) as a yellow oil. Pyranose 27a consumption of the starting material, silica-gel chromatography
signals: 1H NMR (methanol-d4) δ 4.06–3.94 (m, 2H, H-5, H-6), (CHCl3/MeOH 4:1 v/v containing 10% of concd NH4OH) gave
3.87–3.79 (m, 2H, H-1, H-4), 3.87–3.70 (m, 3H, H-3, H-7), the respective Amadori compound 29 (360 mg) exclusively in
3.68 (s, 3H, OCH3), 3.45 (d, J1,1 = 9.8 Hz, 1H, H-1), 2.37 (t, the α-pyranose form in a yield of 70%. [α]D = +7 (c 1.0,
2H, H-12), 1.72–1.55 (m, 4H, H-9, H-11), 1.42–1.31 (m, 3H, MeOH); 1H NMR (methanol-d4) δ 3.93–3.83 (m, 3H, H-3, H-5,
H-10); 13C NMR δ 176.0 (C-13), 158.6 (NCO), 104.5 (C-2), H-7), 3.83–3.71 (m, 2H, H-6, H-7), 3.71–3.62 (m, 1H, H-4),
75.7, 72.0, 70.9, 70.8 (4C, C-3, C-4, C-5, C-6), 62.5 (C-7), 53.4 3.59 (t, 2H, H-13), 3.36 (d, 1H, H-1), 3.12 (d, J1,1 = 12.6 Hz,
(C-1), 52.1 (OCH3), 44.3 (C-8), 34.7 (C-12), 27.8 (C-9), 27.0 1H, H-1), 3.04 (q, 2H, H-8), 1.81–1.69 (m, 2H, H-9), 1.64–1.53
(C-10), 25.7 (C-11); anal. calcd for C15H25NO9: C, 49.61; H, (m, 2H, H-12), 1.51–1.40 (m, 4H, H-13, H-14); 13C NMR δ
6.95; found: C, 49.58; H, 6.97.
96.3 (C-2), 75.2, 74.6, 72.6, 67.9 (4C, C-3, C-4, C-5, C-6), 62.8
(C-13), 62.6 (C-7), 55.0 (C-1), 49.4 (C-8), 33.6 (C-12), 27.5,
1-(N,N-Dibenzylamino)-1-deoxy-α-D-manno-hept-2- 26.8, 26.5 (3C, C-9, C-10, C-11); anal. calcd for C13H27NO7:
ulopyranose (28): General method for sugar elongation was C, 50.50; H, 8.82; found: C, 50.45; H, 8.89.
applied to D-mannose 17 (3 g, 16.7 mmol), pyridine (50 mL),
triethylamine (0.18 mL, 1.3 mmol, 0.08 equiv) and HCN 1-(N-(6-Hydroxyhexyl)amino)-1-N,2-O-carbonyl-1-deoxy-β-
(4.5 mL, 0.11 mmol, 6.9 equiv). After five days, complete D-manno-pyranose (30): General method C was applied to
consumption of the aldose was indicated by TLC, and 8 g of the compound 29 (200 mg, 0.6 mmol) in H2O (5 mL) and 1,4-
crude heptononitrile 18 (a and b) were obtained. For the dioxane (1 mL), Na2CO3 (0.74 g, 6.9 mmol, 6 equiv) and
1626