Reacción #330933

Ecuación de reacción

6

Benzyl 2-acetamido-4,6-di-O-benzyl-2-deoxy-3-O-(2,3-dihydroxypropyl)-α-D-glucopyranoside

acetic anhydride

dichloromethane pyridine

methanol

→

crystalline compound 10

Rendimiento 94.0%

Benzyl 2-acetamido-3-O-(2,3-diacetoxypropyl)-4,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside

Rendimiento 94.0%

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas slowly added at 0° C.
2. 2
   TemperaturaThe mixture was cooled to 0° C.
3. 3
   workup.WAITthe stirring was continued at room temperature for 2 h
4. 4
   OtroThen the mixture was evaporated

Procedimiento

To a stirred solution of 6 (566 mg, 1 mmol) and 4-dimethylaminopyridine (12 mg, 0.1 mmol) in a mixture of dry dichloromethane-pyridine (25:1, 21 ml) acetic anhydride (380 μl, 4 mmol) was slowly added at 0° C. and the mixture was stirred at the same temperature for 1 h and at room temperature overnight. The mixture was cooled to 0° C., methanol (2 ml, 50 mmol) was added and the stirring was continued at room temperature for 2 h. Then the mixture was evaporated and the residue was co-evaporated with toluene (3×10 ml). Chromatography of the residue on a silica gel column (20 g) in toluene-ethyl acetate (1:1) yielded 613 mg (94%) of crystalline compound 10. An analytical sample was crystallized from toluene-N-heptane to give colorless needles corresponding to a mixture of diastereomers of 10 A and B; m.p. 151.5-152.5° C., [α]D +70° (c 0.2, chloroform). IR (tetrachloromethane): 3 446 (N—H, NHAc); 3 090, 3 067, 3 033 (C—H, arom.); 1 747 (C═O, OAc); 1 692 (amide I); 1 498 (amide II); 1 498, 1 454 (arom. ring); 1 371 (CH3, OAc). 1H NMR (ratio diastereomers 5:2); diastereomer A: 1H NMR: 7.16-7.38 m, 15H (H-arom.); 5.68 d, 1H, J=9.8 (NHCOCH3); 5.07 ddt, 1H, J=3.9, 5.0, 5.0, 6.1 [CH2CH(OAc)CH2(OAc)]; 4.88 d, 1H, J=3.7 (H-1); 4.73 d, 1H, J=12.0 (CH2-Ph); 4.69 d, 1H, J=11.7 (CH2-Ph); 4.63 d, 1H, J=12.1 (CH2-Ph); 4.5 d, 1H, J=12.1 (CH2-Ph); 4.45 d, 1H, J=11.7 (CH2-Ph); 4.31 dd, 1H, J=3.9, 11.9 [CH2CH(OAc)CH2(OAc)]; 4.29 ddd, 1H, J=3.7, 9.8, 10.6 (H-2); 4.20 dd, 1H, J=6.1, 11.9 [CH2CH(OAc)CH2(OAc)]; 4.09 d, 1H, J=12.0 (CH2-Ph); 3.91 dd, 1H, J=4.9, 10.5 [CH2CH(OAc)CH2(OAc)]; 3.80 ddd, 1H, J=2.0, 4.0, 10.0 (H-5); 3.72 dd, 1H, J=5.1, 10.5 [CH2CH(OAc)CH2(OAc)]; 3.72 dd, 1H, J=4.0, 10.8 (H-6b); 3.68 dd, 1H, J=8.8, 10.0 (H-4); 3.63 dd, 1H, J=2.0, 10.8 (H-6a); 3.56 dd, 1H, J=8.8, 10.6 (H-3); 1.99 s, 3H (COCH3); 1.99 s, 3H (COCH3); 1.98 s, 3H (NHCOCH3); diastereomer B: 7.16-7.38 m, 15H (H-arom.); 5.76 d, 1H, J=9.5 (NHCOCH3) 5.07 ddt, 1H, J=3.9, 5.0, 5.0, 6.1 [CH2CH(OAc)CH2(OAc)]; 4.92 d, 1H, J=3.6 (H-1); 4.75 d, 1H, J=10.8 (CH2-Ph); 4.73 d, 1H, J=11.9 (CH2-Ph); 4.64 d, 1H, J=12.1 (CH2-Ph); 4.52 d, 1H, J=12.1 (CH2-Ph); 4.51 d, 1H, J=10.8 (CH2-Ph); 4.26 dd, 1H, J=3.9, 11.9 [CH2CH(OAc)CH2(OAc)] 4.25 ddd, 1H, J=3.6, 9.5, 10.6 (H-2); 4.20 dd, 1H, J=6.1, 11.9 [CH2CH(OAc)CH2(OAc)] 4.10 d, 1H, J=11.9 (CH2-Ph); 3.91 dd, 1H, J=4.9, 10.5 [CH2CH(OAc)CH2(OAc)] 3.80 ddd, 1H, J=2.0, 4.0, 10.0 (H-5); 3.76 dd, 1H, J=5.1, 10.5 [CH2CH(OAc)CH2(OAc)] 3.72 dd, 1H, J=4.0, 10.8 (H-6b); 3.68 dd, 1H, J=8.9, 10.0 (H-4); 3.64 dd, 1H, J=2.0, 10.8 (H-6a); 3.57 dd, 1H, J=8.9, 10.6 (H-3); 2.01 s, 3H (COCH3); 1.99 s, 3H (COCH3); 1.97 s, 3H (NHCOCH3). 13C NMR; diastereomer A: 170.59 (OCOCH3); 170.45 (OCOCH3); 169.82 (NHCOCH3); 137.96; 137.89; 137.00; 128.00; 97.19 (C-1); 81.86 (C-3); 77.94 (C-4); 74.85 (CH2-Ph); 73.48 (CH2-Ph); 71.18 (C-5); 70.91; 70.83; 13C NMR spectrum: 69.71 (CH2-Ph); 68.39 (C-6); 62.76; 52.27 (C-2); 23.35 (NHCOCH3); 20.93 (OCOCH3); 20.71 (OCOCH3); diastereomer B: 170.23 (OCOCH3); 170.17 (OCOCH3); 169.75 (NHCOCH3); 137.94; 137.80; 137.07; 97.13 (C-1); 81.43 (C-3); 78.27 (C-4); 74.85 (CH2-Ph); 73.48 (CH2-Ph); 71.20 (C-5); 70.91; 70.86; 69.76 (CH2-Ph); 68.36 (C-6); 62.53; 52.51 (C-2); 23.30 (NHCOCH3); 20.92 (OCOCH3); 20.69 (OCOCH3). For C36H43NO10 calculated: relative molecular mass 649.7, monoisotopic mass 649.3. FAB MS, m/z: 650.3 [M+H]+, 672.3 [M+Na]+. For C36H43NO10 (649.7) calculated: 66.55% C, 6.67% H, 2.16% N; found: 66.22% C, 6.70% H, 2.08% N.

Fuente