Reacción #2137845

Ecuación de reacción

Benzyl chloroformate

Methyl 3-O-benzyl-2,5-dideoxy-2,5-imino-α-D-lyxofuranoside

sodium bicarbonate

→

methyl 3-O-benzyl-N-benzyloxycarbonyl-2,5-dideoxy-2,5-imino-α-D-lyxofuranoside

Rendimiento 76.1%

Disolventes

ether

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroThe ether layer was separated
2. 2
   Extracciónthe aqueous phase further extracted with ether (4×25 ml)
3. 3
   OtroThe combined extracts were dried
4. 4
   Filtraciónfiltered
5. 5
   Otrothe solvent removed
6. 6
   OtroPurification by flash chromatography (ether-hexane 1:10-1:3)

Procedimiento

Methyl 3-O-benzyl-2,5-dideoxy-2,5-imino-α-D-lyxofuranoside (13α) (870 mg, 3.70 mmol) was stirred with a 3:2 mixture of ether and saturated aqueous sodium bicarbonate (60 ml). Benzyl chloroformate (1.57 ml, 11.1 mmol) was added to the mixture which was stirred at room temperature for 12 hours. The ether layer was separated and the aqueous phase further extracted with ether (4×25 ml). The combined extracts were dried, filtered and the solvent removed. Purification by flash chromatography (ether-hexane 1:10-1:3) afforded methyl 3-O-benzyl-N-benzyloxycarbonyl-2,5-dideoxy-2,5-imino-α-D-lyxofuranoside (1.04 g, 76%) as a white crystalline solid, m.p. 74°-75° C., Rf 0.2 (ether-hexane 1:3); [α]20D +12.0° (c, 0.98 in chloroform); νmax (chloroform) 2940, 1695 (C=O), 1420, 1260, 1230, 1090 and 750 cm-1 ; 1H NMR δ 3.38, 3.41 (3H, 2× s, CH3); 3.3-3.7 (2H, m, 5,5'-H); 4.05-4.90 (5H, m, H-3, H-2, H-4, CH2Ph); 5.12-5.20 (3H, m, H-1, CH2 -Z); 7.2-7.4 (10H, m, 2×H-Ph). 13C NMR δ 50.71 (t, C-5); 55.15, 55.33 (2×q, Me); 59.63, 60.17 (2×d, C-2); 66.95, 67.08 (2×t, CH2 -Z); 72.28 (t, CH2Ph); 75.09, 75.49, 77.93, 78.48 (4×d, C-3, C-4); 105.67, 105.90 (d, C-1); 127.83, 127.92, 128.15, 128.64 (4×d, HC-Ph); 136.68, 137.46 (2×s, C-Ph); 155.68, 155.81 (2×s, C=O). m/z: 91 (100%), 108 (25%), 158 (20%), 370 (M+H+, 10%). (Found C, 67.98; H, 6.39; N, 3.60. C21H23NO5 requires C, 68.28; H, 6.28; N, 3.79). Methyl 3-O-benzyl-2,5-dideoxy-2,5-imino-β-D-lyxofuranoside (13β) (829 mg, 3.53 mmol) was treated likewise giving methyl 3-O-benzyl-N-benzyloxycarbonyl-2,5-dideoxy-2,5-imino-β-D-lyxofuranoside (1.18 g, 90%) as a clear oil, Rf 0.35 (ether-hexane 1:3); [α]20D -75.2° (c, 0.83 in chloroform); νmax (film) 2930, 1705 (C=O), 1425, 1275, 1255, 1105 and 750 cm-1 ; 1H NMR δ 3.36, 3.42 (3H, 2×s, CH3); 3.50 (1H, 2×d 5-H); 3.67 (1H, 2×d, H-5'); 4.02-4.06 (1H, m, H-3); 4.29 (1H, bs, H-2); 4.49, 4.54 (1H, bs and dd, H-4); 4.52-4.65 (2H, m, CH2Ph); 5.0-5.2 (2H, 2×dd, CH2Ph); 5.21 (1H, s, H-1); 7.28-7.38 (10H, m, H-Ph). 13C NMR δ 50.02 (t, C-5); 55.70, 55.89 (2×q, Me); 60.17, 59.52 (2×d, C-2); 66.79 (t, CH2 -Z); 72.00, 72.10 (t, CH2Ph); 77.56, 78.08, 78.52, 79.18 (4×d, C-3, C-4); 104.71, 105.11 (2×d, C-1); 128.79, 127.96, 128.33, 128.61, 128.78 (5×d, HC-Ph); 137.09, 137.22 (2×s, C-Ph); 156.20, 156.45 (2×s, C=O). m/z: 91 (100%), 370 (M+H+, 60%), 202 (30%). (Found C, 68.08; H, 6.39; N, 3.40. C21H 23 NO5 requires C, 68.28; H, 6.28; N, 3.79).

Fuente