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

2) Synthesis of the tetravalent dendron of the α(1,2)pseudomannobiose 12a
To a solution of the functionalized scaffold dendron 1 1 (6.0 mg, 0.00718 mmol,
1 eq) in 150 μi_ of dry DMA under nitrogen atmosphere, HATU (22 mg, 0.0575
mmol, 8 eq) and DIPEA (20 μL , 0.1 157 mmol, 16 eq) were added. After 15
minutes a solution of 13 (23.4 mg, 0.05349 mmol, 8eq) in dry DMA (210 μL)
was added. The reaction was stirred at room temperature for 3 days. MALDI
mass analysis of a sample of the reaction mixture showed the completion of
the reaction.
The reaction mixture was diluted in methanol and charged directly onto a LH-
20 Sephadex column in methanol. Slow elution led to the purification of the
product 12a, which was isolated in good yield (16.9 mg, 94% yield). [α] =
+36.66 (c: 0.78 , CH 3 OH). 1 H-NMR (400 MHz, D 2 O) δ (ppm): 4.93 (s, 4H, H 1 ),
4.27 (bs, 6H, OCH 2 CH 2 N 3 , CH 2 O a), 4.18 (bs, 8H, CH 2 O b), 3.91 (bs, 8H, D 2 ,
H 2 ), 3.78 (d, 4H, H 6 , J ge m= J 6 B-S = 12 Hz), 3.76-3.71 (m, 4H, H 3 ) , 3.69-3.59 (m,
8H, H 6A> Di), 3.63 (s, 24H, OCH 3 ), 3.59-3.49 (m, 18H, H 4 , H 5 , H 7 , CH 2 N 3 ), 3.30
(bt, 8H, H 8 ), 2.91-2.72 (m, 8H, D 4 , D 5 ), 2.65-2.56 (m, 8H, CH 2 COO), 2.54-2.45
(m, 8H, CH 2 CONH), 2.10-1.99 (m, 8H, D 6θq , D 3eq ), 1.81-1 .64 (m, 8H, D 6ax , D 3ax ),
1.26 (s, 3H, CH 3 a ), 1.19 (s, 6H, CH 3 b').