W0 2011/000721 A1 I||||||||||||||||||||||||||||||||||||||||||||||||||||||||| - Questel

3.52 (ddd, 1H, H 8A , J 8 A-/ = 6.0 Hz, J 8A- r = 3.2 Hz). 13 C-NMR (D 2 O, 100 MHz) δ
(ppm): 99.6 (C1), 72.7 (C4), 70.2 (C3), 69.7 (C2), 66.5 (C5), 66.1 (C7), 60.7
(C6), 50.0 (C8). MS (ESI) [C 8 H 15 N 3 O 6 Na] + = 272.6, [C 8 H 15 N 3 O 6 K] + = 288.4.
[a] =+55.64 (c: 1.2, MeOH). To a solution of the azidoethylmannoside ( 1 .95
g , 7.81 mmol, 1 eq) in dry pyridine (18 mL) at 0 0 C a solution of TBDMSCI
(1.41 g , 9.37 mmol, 1.2 eq) in dry pyridine (8 mL) was added. The reaction was
stirred at 0°C for one hour, then warmed at room temperature. The reaction,
monitored by TLC (8:2 CHCI iMeOH), was complete after 4 hours. Then Ac O
(4.43 mL, 46.9 mmol, 6 eq) was added and the reaction mixture was stirred
overnight. The solvent was then evaporated at reduced pressure; the crude
was diluted with EtOAc, washed with 3N HCI, then with saturated NaHCO 3
solution and with water till neutral pH. The organic phase was dried over
anhydrous sodium sulfate and the solvent was evaporated at reduced
pressure. The crude was purified by flash chromatography (8:2 Hex:EtOAc)
obtaining 3.10 g of a colourless sticky oil (yield 81%)
[af° =+43.09 (c: 0.955, CHCI 3 ). 1 H-NMR (400 MHz, CDCI3) δ (ppm): 5.36
(dd, 1H , H 3 , H 4 , 10.0 Hz), 5.24
(dd, 1H, H 2 , J 2-1 =2.0 Hz), 4.84 (d, 1H, H 1 ), 3.92-3.81 (m, 2H, H 7 , H 5 ), 3.70 (t,
2H, H 6 , J 6-5 = 4 Hz), 3.68-3.60 (m, 1H, H 7A ), 3.51-3.38 (m, 2H, H 8 ), 2.13 (s, 3H,
CH 3 CO), 2.03 (s, 3H, CH 3 CO), 1.99 (s, 3H, CH 3 CO), 0.90 (s, 9H, C(CH 3 ) 3 ),
0.06 (s, 3H, CH 3 Si), 0.05 (s, 3H, CH 3 Si)- 13 C-NMR (100 MHz, CDCI 3 ) δ (ppm):
170.2 (COCH 3 ), 170.1 (COCH 3 ), 169.8 (COCH 3 ), 97.6 (C1 ), 7 1.9 (C5), 69.8
(C2), 69.4 (C3), 66.9 (C7), 66.6 (C4), 62.4 (C6), 50.5 (C8), 25.9 (C(CH 3 ) 3 ),
21.0 (CH 3 CO), 20.9 (CH 3 CO), 20.8 (CH 3 CO), 18.4 (C(CH 3 ) 3 ), -5.2 (SiCH 3 ), -5.3
(SiCH 3 ). HRMS (ESI) : Calculated for [C 20 H 35 N 3 O 9 SiNa] + = 512.20348
Experimental = 512.20261 .