30
C. Limousin et al./Carbohydrate Research 312 (1998) 23±31
Methyl 2,3-di-O-benzyl-4,6-dichloro-4,6-dideoxy-
ꢀ-d-galactopyranoside (13).ÐFor experimental
details, see Table 2, entries 1,2,3. Compound 13
3.93 (dd, 1 H, J2,3=J3,4=9 Hz, H-3), 3.88±3.80 (m,
3 H, H-2,6a,6b), 3.50 (dd, 1 H, H-2), 3.42 (s, 3 H,
CH3O). Anal. Calcd for C21H24Cl2O4: C, 61.32; H,
5.88; Cl, 17.24. Found: C, 61.31; H, 5.98; Cl, 17.31.
Methyl 2,3-di-O-benzyl-6-chloro-6-deoxy-ꢀ-d-
galactopyranoside (19).ÐFor experimental details,
see Table 2, entries 15 and 16. Compound 19 was
was isolated as syrup. [ꢀ]d+63ꢀ (c 1.2, CHCl3); H
1
NMR (250 MHz, CDCl3): ꢂ 7.45±7.20 (m, 10 H,
Ph), 4.76 (m, 4 H, 2 CH2Ph), 4.60 (d, 1 H, J1,2
3.4 Hz, H-1), 4.45 (dd, 1 H, J3,4 3, J4,5 0.8 Hz, H-4),
4.05 (m, 2 H, H-3,5), 3.90 (dd, 1 H, J2,3 9.6 Hz, H-
2), 3.60 (d, 2 H, J5,6 6 Hz, H-6a,6b), 3.40 (s, 3 H,
CH3O). Anal. Calcd for C21H24Cl2O4: C, 61.32; H,
5.88; Cl, 17.24; O, 15.56. Found: C, 61.51; H, 5.89;
Cl, 16.98; O, 15.81.
Methyl 2,3-di-O-benzyl-6-chloro-6-deoxy-ꢀ-d-
glucopyranoside (14).ÐFor experimental details,
see Table 2, entries 4 and 5. Compound 14 was
isolated as a white solid. mp 43±45 ꢀC; [ꢀ]d+89ꢀ (c
ꢀ
isolated as a white solid. mp 94±96 C (pentane);
[ꢀ]d+44ꢀ (c 1.5, CHCl3); 1H NMR (250 MHz,
CDCl3): ꢂ 7.45±7.20 (m, 10 H, Ph), 4.72 (2d, 2 H,
CH2Ph), 4.70 (2d, 2 H, CH2Ph), 4.64 (d, 1 H, J1,2
3 Hz, H-1), 4.05 (m, 1 H, H-4), 3.90±3.75 (m, 3 H,
H-2,3,5), 3.70±3.60 (m, 2 H, H-6a,6b), 3.46 (m, 1
H, H-4), 3.39 (s, 3 H, CH3O). Anal. Calcd for
C21H25ClO5: C, 64.20; H, 6.41; Cl, 9.03. Found: C,
64.31; H, 6.41; Cl, 9.22.
ꢀ
1
1.1, MeOH); lit. mp 50±51 C; [ꢀ]d+81.5ꢀ [21]; H
NMR (300 MHz, CDCl3): ꢂ 7.45±7.20 (m, 10 H,
Ph), 4.90 (2d, 2 H, CH2Ph), 4.65 (m, 3 H, CH2Ph
and H-1), 3.80 (m, 3 H, H-3,5,6a), 3.70 (dd, 1 H,
J5,6b 5.6 J6a,6b 11.4 Hz, H-6b), 3.55 (dd, 1 H, J1,2
3.6, J2,3 9.6 Hz, H-2), 3.46 (m, 1 H, H-4), 3.40 (s, 3
H, CH3O).
Methyl 2,3-di-O-benzyl-4,6-dibromo-4,6-dide-
oxy-ꢀ-d-glucopyranoside (20).ÐFor experimental
details, see Table 2, entries 17 and 18. Compound
20 was isolated as a syrup. [ꢀ]d+47ꢀ (c 1.5, CHCl3);
1H NMR (300 MHz, CDCl3): ꢂ 7.45±7.20 (m, 10 H,
Ph), 4.90 (2d, 2 H, CH2Ph), 4.73 (2d, 2 H, CH2Ph),
4.66 (d, 1 H, J1,2 3.6 Hz, H-1), 4.01 (m, 2 H, H-3,5),
3.86 (t, 1 H, J3,4=J4,5=9 Hz, H-4), 3.81 (dd, 1 H,
J5,6a 2.2, J6a,6b 11 Hz, H-6a), 3.70 (dd, 1 H, J5,6b
5 Hz, H-6b), 3.50 (dd, 1 H, J2,3 9.4 Hz, H-2), 3.42
(s, 3 H, CH3O). Anal. Calcd for C21H24Br2O4: C,
50.42; H, 4.84; Br, 31.95. Found: C, 50.42; H, 4.81;
Br, 32.01.
Methyl 2,3-di-O-benzyl-4,6-dibromo-4,6-dideoxy-
ꢀ-d-galactopyranoside (15).ÐFor experimental
details, see Table 2, entries 6, 7, 8, 9. Compound 15
was isolated as a syrup. [ꢀ]d+59ꢀ (c 1.13, CHCl3);
1H NMR (200 MHz, CD3COCD3): ꢂ 7.30±7.10 (m,
10 H, Ph), 4.50 (m, 5 H, 2 CH2Ph and H-1), 4.15
(d, 1 H, J3,4 3.6, J4,5 0.8 Hz, H-4), 3.95 (dd, 1 H,
J1,2 3.6, J2,3 9.4 Hz, H-2), 3.75 (dd, 1 H, J3,4 9.6 Hz,
H-3), 3.60 (m, 1 H, H-5), 3.40 (dd, 1 H, J5,6a 2,
J6a,6b 10 Hz, H-6a), 3.10 (s, 3 H, CH3O), 3.05 (dd, 1
H, J5,6b 5 Hz, H-6b). Anal. Calcd for C21H24Br2O4:
C, 50.42; H, 4.84. Found: C, 50.48; H, 4.87.
Methyl 2,3-di-O-benzyl-6-bromo-6-deoxy-ꢀ-d-
galactopyranoside (21).ÐFor experimental details,
see Table 2, entries 19 andꢀ20. Compound 21 was
isolated as a solid. mp 105 C (heptane); [ꢀ]d+40ꢀ
1
(c 1.7, CHCl3); H NMR (250 MHz, CDCl3): ꢂ
7.40±7.20 (m, 10 H, Ph), 4.80±4.60 (m, 4 H, 2
CH2Ph), 4.64 (d, 1 H, J1,2 3 Hz, H-1), 4.07 (s, 1 H,
H-4), 3.93±3.78 (m, 3 H, H-2,3,5), 3.58±3.47 (m, 2
H, H-6a,6b), 3.40 (s, 3 H, CH3O). Anal. Calcd for
C21H25BrO5: C, 57.65; H, 5.76; Br, 18.27. Found:
C, 57.43; H, 5.85; Br, 18.56.
Methyl 2,3-di-O-benzyl-6-bromo-6-deoxy-ꢀ-d-
glucopyranoside (16).ÐFor experimental details,
see Table 2, entries 10, 11, 12. Compound 16 was
isolated as a syrup. [ꢀ]d+40ꢀ (c 1.11, CHCl3); H
1
NMR (300 MHz, CDCl3): ꢂ 7.45±7.20 (m, 10 H,
Ph), 4.90 (d, 2 H, CH2Ph), 4.65 (m, 3 H, CH2Ph
and H-1), 3.70 (m, 3 H, H-3,5,6a), 3.50 (m, 3 H, H-
2,4,6b), 3.40 (s, 3 H, CH3O). Anal. Calcd for
C21H25BrO5. 1/2 H2O: C, 56.51; H, 5.87; Br, 17.90.
Found: C, 56.55; H, 5.67; Br, 17.42.
Methyl 6-chloro-6-deoxy-ꢀ-d-glucopyranoside
(23).ÐFor experimental details, see Table 2,
entries 21, 22, 26, 27. Compound 23 was isolated as
ꢀ
a solid. mp 112±114 C; [ꢀ]d+151ꢀ (c 1, MeOH);
lit. mp 111±112 ꢀC; [ꢀ]d+153ꢀ [7].
Methyl
2,3-di-O-benzyl-4,6-dichloro-4,6-dide-
Methyl 6-bromo-6-deoxy-ꢀ-d-glucopyranoside
(24).ÐFor experimental details, see Table 2,
entries 23, 24, 25. Compound 24 was obtained as a
oxy-ꢀ-d-glucopyranoside (18).ÐFor experimental
details, see Table 2, entries 13 and 14. Compound
18 was isolated as syrup. [ꢀ]d+13.5ꢀ (c 1.4, CHCl3);
1H NMR (300 MHz, CDCl3): ꢂ 7.45±7.20 (m, 10 H,
Ph), 4.89 (2d, 2 H, CH2Ph), 4.72 (2d, 2 H, CH2Ph),
4.65 (d, 1 H, J1,2 3 Hz, H-1), 3.99 (m, 1 H, H-5),
ꢀ
white solid. mp 125 C; [ꢀ]d+130ꢀ (c 1.1, MeOH);
lit. mp 126±127 ꢀC; [ꢀ]d+132ꢀ [22].
A small quantity of dibromide 25 was also isolaꢀted
and recrystallized from pentane. mp 130±132 C;