Ingrid 't Hart

66 Chapter 3 3 (2S,3R,4E)-2-azido-3-O-benzoyloxy-octadec-4-enyl 2- O -benzyl-3- O -(2-naphthyl) methyl-4,6- O -di- tert- butylsilanediyl-β-D-galactopyranosyl-(1→4)-2,3,6-tri- O -benzyl- β-D-galactopyranosyl-(1→4)-2,3,6-tri- O -benzyl-β-D-glucopyranoside (9). A mixture of acceptor 7 (695 mg, 0.55 mmol), donor 8a (483 mg, 0.75 mmol) and 4 Å molecular sieves was s�rred in DCM for 1 h. The mixture was cooled to - 35 °C and N -iodosuccinimide (242 mg, 1.07 mmol) and triflic acid (5 µL, 0.05 mmol) were added. The mixture was allowed to warm to -25 °C and a�er 1 h the reac�on was quenched by addi�on of Et 3 N. The mixture was filtered over Celite and concentrated in vacuo . The obtained residue was purified by silica gel chromatography using Toluene:EtOAc (1:0 to 15:1 v/v) as the eluent. Subsequent purifica�on by prepara�ve TLC using Toluene:EtOAc (95:7 v/v) as the eluent provided �tle compound 9 (286 mg, 29%). 1 H NMR (400 MHz, CDCl 3 ) δ 8.06 (2H, d, J = 7.4 Hz, H-Ar), 7.89 – 7.70 (5H, m, H-Ar), 7.68 (1H, s, H-Ar), 7.55 (2H, t, J = 7.6 Hz, H-Ar), 7.50 – 7.36 (7H, m, H-Ar), 7.35 – 7.06 (30H, m, H-Ar), 5.93 – 5.80 (1H, m, CH=C H -CH 2 ), 5.65 (1H, dd, J = 7.9, 3.7 Hz, C H OBz), 5.59 – 5.48 (1H, m, J = 15.8, 7.2 Hz, CHOBz-C H =CH), 5.07 (1H, d, J = 11.3 Hz, CH H ), 4.97 (1H, d, J = 3.3 Hz, H-1, Gal-III), 4.86 (1H, d, J = 11.0 Hz, CH H ), 4.82 – 4.63 (7H, m), 4.61 – 4.40 (6H, m, H-1, Gal-II; H-4, Gal-III), 4.37 (1H, d, J = 7.7 Hz, H-1, Glc-I), 4.35 – 4.23 (3H, m), 4.13 – 4.07 (1H, m), 4.07 – 3.87 (7H, m, H-4, Gal-II; H-2, Gal-III; C H N 3 ; H-4, Glc-I; H-3, Gal-III), 3.82 – 3.65 (4H, m, C H 2 -CHN 3 ), 3.63 – 3.47 (4H, m, H-3, Glc-I; H-2, Gal-II), 3.46 – 3.40 (1H, m, H-2, Glc-I), 3.38 – 3.29 (2H, m), 3.26 (1H, dd, J = 10.0, 2.6 Hz, H-3, Gal-II), 2.01 (2H, dt, J = 14.0, 6.9 Hz, CH=CH-C H 2 ), 1.42 – 1.16 (22H, m, J = 26.4, 7.0 Hz, 11 x CH 2 ), 1.09 – 0.94 (18H, m, J = 27.7, 12.6 Hz, 2x t -Bu), 0.87 (3H, t, J = 6.7 Hz, CH 3 , Sph). 13 C NMR (101 MHz, CDCl 3 ) δ 165.1 (C=O, Bz), 139.2, 138.8, 138.7 (CH= C H-CH 2 ), 138.6, 138.5, 138.3, 138.2, 136.7, 133.3, 133.1, 132.9, 130.0, 129.8, 128.6, 128.4, 128.4, 128.4, 128.3, 128.2, 128.2, 128.1, 128.1, 128.0, 127.9, 127.8, 127.7, 127.7, 127.6, 127.6, 127.5, 127.4, 127.4, 127.4, 127.3, 126.2, 126.0, 125.9, 125.9, 125.7, 125.7, 122.7 (CHOBz= C H=CH), 103.4 (C-1, Glc-I), 102.9 (C-1, Gal-II), 100.1 (C-1, Gal-III), 82.3 (C-3, Glc-I), 81.6 (C-2, Glc-I), 81.1 (C-3, Gal-II), 79.0 (C-2, Gal-II), 78.0 (C-3, Gal-III), 76.9, 75.29, 75.17, 75.0 ( C HOBz), 74.88, 74.2 (C-2, Gal-III), 73.6, 73.4 (C-4, Gal-II), 73.32, 73.15, 73.09, 72.16, 71.2 (C-4, Gal-III), 70.57, 68.46, 68.32, 68.14, 67.60, 67.5 (C-4, Glc-I), 67.06, 64.0 ( C HN 3 ), 32.4 (CH=CH- C H 2 ), 31.9, 29.7, 29.7, 29.7, 29.6, 29.4, 29.4, 29.2, 28.7, 27.7 (3x CH 3 , t -Bu) 27.3 (3x CH 3 , t -Bu), 23.3, 22.7, 20.7, 14.1 (CH 3 , Sph). ESI HRMS ( m/z ): [M + NH 4 ] + calcd for C 111 H 135 N 3 O 18 Si; 1843.9848 found 1843.9883. Para- methoxyphenyl 2,3,4,6-tetra- O -acetyl-β-D-galactopyranosyl-(1→3)-4,6- O - acetyl-2-[(2,2,2-trichloroethoxy)carbonylamino]-β-D-galactopyranosyl-(1→3)-2- O - benzyl-4,6- O- di- tert- butyl-silanediyl-α-D- galactopyranosyl-(1→4)-2,3,6-tri- O -benzyl-β- D-galactopyranosyl-(1→4)-2,3,6-tri- O -benzyl- β-D-glucopyranoside (10). Compound 10 was synthesized as described before (Chapter 2; 16b). 28 O O O NapO BnO O O OBn BnO OBn O O OBn BnO BnO Si O C 13 H 27 OBz N 3 O AcO OAc O TrocHN O AcO OAc AcO AcO O O O O BnO O O OBn BnO OBn O O OBn BnO BnO Si OpMP