تفاعل #162019

معادلة التفاعل

sodium ascorbate

azide

3β-(Prop-2-ynyloxy)cholestanol

azide

3-Azidopropyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl-(1→3)-2,4,6-tri-O-acetyl-α-D-mannopyranosyl-(1→2)-3,4,6-tri-O-acetyl-α-D-mannopyranoside

→

triazole

المردود 81.5%

3-{4-(Cholestan-3β-yl-oxymethyl)-[1,2,3]triazol-1-yl}propyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl-(1→3)-2,4,6-tri-O-acetyl-α-D-mannopyranosyl-(1→2)-3,4,6-tri-O-acetyl-α-D-mannopyranoside

المردود 81.5%

المذيبات

DCM t-BuOH

DCM

toluene

EtOAc

ظروف التفاعل

المعالجة

1. 1
   غسيلwashed with satd
2. 2
   استخلاصThe aqueous phase was re-extracted with EtOAc (3×20 mL), organic extracts
3. 3
   غسيلwashed with brine (20 mL)
4. 4
   تجفيفdried (Na2SO4)
5. 5
   تركيزconcentrated in vacuo
6. 6
   أخرىto afford the crude product as a yellow foam (475 mg)
7. 7
   أخرىThe crude product was purified on a column of silica gel (25×2.5 cm, toluene—EtOAc, 1:2→1:3→1:4)

الإجراء التجريبي

3β-(Prop-2-ynyloxy)cholestanol (156 mg, 2 eq., 0.367 mmol) and the azide 45 (185 mg, 0.183 mmol) were dissolved in a mixture of DCM/t-BuOH (3:2, w/w, 0.4 M, 0.562 mL). To the mixture were added an aqueous solution of CuSO4 (0.3 M, 0.1 eq., 0.061 mL) and a aqueous solution of sodium ascorbate (1 M, 0.3 eq., 0.055 mL) and the mixture was vigorously stirred without light for 48 h. TLC analysis (toluene:EtOAc, 1:1) showed the end of the reaction with the appearance of a more polar product than the starting azide. The mixture was diluted with DCM (50 mL) and washed with satd. NaHCO3-solution (3×30 mL). The aqueous phase was re-extracted with EtOAc (3×20 mL), organic extracts were combined, washed with brine (20 mL), dried (Na2SO4) and concentrated in vacuo to afford the crude product as a yellow foam (475 mg). The crude product was purified on a column of silica gel (25×2.5 cm, toluene—EtOAc, 1:2→1:3→1:4) to yield the triazole 46 as white foam (214 mg, 81%). 1H NMR (CDCl3, 400 MHz) δ 7.76 (s, 1H, ═CH), 5.18-5.36 (m, 6H, 3×H4, H2II, H3I, H3III), 5.06 (dd 1H, JH2-H3=3.2, H2III), 5.02 (d, 1H, JHI-H2=1.7, H1III), 4.94 (d, 2H, JHI-H2=1.6, H-1II), 4.92 (d, 1H, JHI-H2=1.6, H1I), 4.71 (s, 2H, OCH2), 4.49 (t, 2H, J=6.6, CH2N), 4.30 (dd, 1H, JH6a-H6b=−11.9, JH6-H5=4.0, H6a), 3.96-4.26 (m, 9H, 2×H6a, 3×H6b, H2I, H3II, H5I, H5II or H5III), 3.92 (ddd, 1H, H5II or H5III), 3.43 (m, 2H, OCH2, H-3 Chol), 2.31 (m, 2H, CH2), 2.19, 2.145, 2.142, 2.11, 2.09, 2.08, 2.06, 2.04, 1.99 (s, 30H, 10×Ac), 1.90 (quintet, 2H, J=6.6, CH2), 0.56-2.04 (m, 33H, 12CH2, 9CH), 0.89 (d, 3H, J=6.8, cholestanyl-CH3), 0.858 (d, 3H, J=6.8, cholestanyl-CH3), 0.855 (d, 3H, J=6.8, cholestanyl-CH3), 0.79 (s, 3H, cholestanyl-CH3), 0.64 (s, 3H, cholestanyl-CH3).

المصدر