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J. K. Twibanire et al. / Tetrahedron 66 (2010) 9602e9609
CH3), 2.92 (t, J¼7 Hz, 4H, PhCH2), 3.61 (AB q, DnAB¼22.3 Hz,
JAB¼10.5 Hz, 8H, CH2OH), 4.27 (t, J¼7 Hz, 4H, CH2O), 7.19 (s, 4H,
CH2CH2OC]O), 6.88 (s, 4H, PhH); 13C NMR (125.7 MHz, methanol-d4)
175.8 (4C]O), 174.4 (2C]O), 154.4, 116.9 (PhC), 67.6 (OCH2CH2O),
66.3 (4CH2OC]O), 65.7 (CH2OH), 65.0 (OCH2CH2O), 51.7 (4Cquat), 47.7
(2Cquat), 18.1 (2CH3), 17.2 (4CH3). HR ESI MS m/z calcd for C40H62NaO22
917.3625; found 917.3629.
d
PhH); 13C NMR (125.7 MHz, methanol-d4)
d
176.6 (C]O), 137.7,
130.1 (PhC), 66.3 (CH2O), 65.8 (CH2OH), 51.5 (Cquat), 35.6 (PhCH2),
17.3 (CH3). HR EIMS m/z calcd for C20H30NaO8 421.1833; found
421.1830.
4.4.9. 1,4-Bis-(2-(2,20,200-tris(benzyloxymethyl)ethanoyloxy)ethoxy)
benzene (28). Compound 28 was synthesized as described above in
the general dendritic ester procedure. The core moiety (3) (0.630 g,
3.18 mmol), dry pyridine (6 mL), CH2Cl2 (18 mL), DMAP (0.210 g,
1.72 mmol), and the anhydride 23 (6.15 g, 7.47 mmol) were stirred
at rt for 12 h under nitrogen. After work up and purification as
described above, the product was obtained as a colorless crystalline
solid (hexanes/EtOAc; 3:1; Rf 0.35) (2.99 g, 94%): mp 70 ꢀC; 1H NMR
4.4.5. 1,4-Bis(2-((cis-5-methyl-r-2-phenyl-1,3-dioxan-5-yl)meth-
anoyloxy)ethoxy)benzene (24). Compound 24 was synthesized as
described above in the general dendritic ester procedure. 1,4-Bis-
(2-hydroxyethoxy)benzene (3, 0.500 g, 2.52 mmol), dry pyridine
(6 mL), CH2Cl2 (18 mL), DMAP (0.135 g, 1.11 mmol), and the anhy-
dride 17 (2.58 g, 6.05 mmol) were stirred at rt for 4 h under ni-
trogen. After work up and purification as described above, the
product was obtained as a colorless solid (1.48 g, 97% yield): mp
(500.13 MHz, CDCl3)
d
3.71 (s, 12H, 6CquatCH2O), 4.01 (t, J¼5 Hz, 4H,
145 ꢀC; 1H NMR (500.13 MHz, CDCl3)
d
1.04 (s, 6H, CH3), 3.65 (d,
2PhOCH2), 4.42 (t, J¼5 Hz, 4H, 2CH2OC]O), 4.46 (s, 12H, 6CH2
J¼11.5 Hz, 4H, H-4ax, H-6ax), 4.16 (t, J¼5 Hz, 4H, PhOCH2O), 4.53 (t,
J¼5 Hz, 4H, OCH2CH2O), 4.68 (d, J¼11.5 Hz, 4H, H-4eq, H-6eq), 5.45
(s, 2H, H-2), 6.81 (s, 4H, PhH), 7.28e7.44 (m, 10H, PhH); 13C NMR
benzylic), 6.69 (s, 4H, PhH), 7.21e7.27 (m, 30H, PhH); 13C NMR
(125.7 MHz, CDCl3) d 172.6 (C]O),153.1,138.5, 128.4, 127.52,127.46,
115.8 (PhC), 73.3 (6CH2 benzylic), 68.0 (6CquatCO), 66.6 (2PhOC),
63.0 (2COC]O), 53.9 (Cquat). HR ESI MS m/z calcd for C62H66NaO12
1025.4446; found 1025.4429.
(125.7 MHz, CDCl3)
d 174.1 (C]O), 153.2, 138, 129.1, 128.3, 126.4,
116.1 (PhC), 102 (C-2), 73.7 (C-4, C-6), 66.9 (OCH2CH2O), 63.6
(OCH2CH2O), 42.7 (Cquat), 18.0 (CH3). HR ESI MS m/z calcd for
C34H38NaO10 629.2357; found 629.2352.
4.4.10. 1,4-Bis-(2-(2,20,200-tris(hydroxymethyl)ethanoyloxy)ethoxy)
benzene (29). Using the general procedure for deprotection de-
scribed above, 28 (1.74 g, 1.73 mmol), dissolved in dry CH2Cl2
(15 mL), dry MeOH (30 mL), and dry THF (15 mL) afforded 29 as
a colorless crystalline solid (0.77 g, 96% yield): mp 150e151 ꢀC; 1H
4.4.6. 1,4-Bis-(2-(2,20-bis(hydroxymethyl)propanoyloxy)ethoxy)ben-
zene (25). Using the general procedure for deprotection described
above, 24 (1.18 g, 1.95 mmol) dissolved in dry CH2Cl2 (15 mL), dry
methanol (30 mL) and dry THF (15 mL) afforded hydroxyl-termi-
nated 25 as a colorless solid (0.83 g, 99% yield): mp 155e156 ꢀC; 1H
NMR (500.13 MHz, methanol-d4)
J¼5 Hz, 4H, 2PhOCH2), 4.42 (t, J¼5 Hz, 4H, 2CH2OC]O), 6.90 (s, 4H,
PhH); 13C NMR (125.7 MHz, methanol-d4)
175.4 (C]O), 154.7,
d 3.77 (s, 12H, 6CH2O), 4.17 (t,
NMR (500.13 MHz, methanol-d4)
d
1.16 (s, 6H, CH3), 3.66 (AB q,
d
DnAB¼29.5 Hz, JAB¼11 Hz, 8H, CH2OH), 4.16 (t, J¼5 Hz, 4H, OCH2
116.5 (PhC), 71.1 (2PhOC), 61.8 (2COC]O), 61.5 (6COH), 57.1
(Cquat). HR ESI MS m/z calcd for C20H30NaO12 485.1629; found
485.1656.
-
CH2O), 4.40 (t, J¼5 Hz, 4H, OCH2CH2O), 6.89 (s, 4H, PhH); 13C NMR
(125.7 MHz, methanol-d4)
d 176.5 (C]O), 154.6, 116.9 (PhC), 67.9
(OCH2CH2O), 65.8 (CH2OH), 64.3 (OCH2CH2O), 51.6 (Cquat), 17.3
(CH3). HR ESI MS m/z calcd for C20H30NaO10 453.1731; found
453.1740.
4.4.11. 1,4-Bis-(2-(2,20,200-tris((cis-5-methyl-r-2-phenyl-1,3-dioxan-
5-yl)methanoyloxy-methyl)ethanoyloxy)ethoxy)benzene
(30). Compound 30 was synthesized as described above in the
general procedure for dendritic ester formation. Dendrimer 29
(0.550 g, 1.19 mmol), dry pyridine (4 mL), CH2Cl2 (12 mL), DMAP
(0.262 g, 2.14 mmol), and the anhydride 17 (3.80 g, 8.91 mmol)
were stirred at rt for 7 h under nitrogen. Water (4 mL) was added
and the ester product precipitated immediately. The product was
collected using suction filtration and was washed with methanol
(3ꢂ5 mL) to afford a colorless crystalline solid (1.95 g, 97% yield):
4.4.7. 1,4-(Bis-(2-(2,20-bis(cis-5-methyl-r-2-phenyl-1,3-dioxan-5-yl)
methanoyloxy-methyl)-propanoyloxy)ethoxy)benzene
(26). Compound 26 was synthesized as described above in the
general dendritic ester procedure. Compound 25 (0.800 g,
1.86 mmol), dry pyridine (5 mL), CH2Cl2 (15 mL), DMAP (0.200 g,
1.64 mmol), and the anhydride 17 (3.80 g, 8.91 mmol) were
stirred at rt for 10 h under nitrogen. After work up and purifi-
cation as described above, the product was obtained as a color-
less solid (2.13 g, 92% yield): mp 145 ꢀC; 1H NMR (500.13 MHz,
mp 183e185 ꢀC; 1H NMR (500.13 MHz, acetone-d6/DMSO-d6)
d
3.70
(d, J¼11.5 Hz, 12H, 6H-4ax, 6H-6ax), 3.93 (t, J¼4.5 Hz, 4H, 2PhOCH2),
CDCl3)
d
0.94 (s, 12H, 4CH3), 1.28 (s, 6H, 2CH3), 3.59 (d,
4.27 (t, J¼4.5 Hz, 4H, 2CH2OC]O), 4.44 (d, J¼11.5 Hz, 12H, 6H-4eq
,
J¼11.5 Hz, 8H, H-4ax, H-6ax), 3.89 (t, J¼5 Hz, 4H, OCH2CH2O),
4.27 (t, J¼5 Hz, 4H, OCH2CH2O), 4.41 (AB q, DnAB¼6 Hz,
JAB¼11 Hz, 8H, 4CH2OC]O), 4.58 (m, 8H, H-4eq, H-6eq), 5.42 (s,
4H, H-2), 6.69 (s, 4H, PhH), 7.28e7.42 (m, 20H, PhH); 13C NMR
6H-6eq), 4.47 (s, 12H, 2Cquat(CH2)3), 5.50 (s, 6H, H-2), 6.73 (s, 4H,
PhH), 7.30e7.38 (m, 30H, PhH); 13C NMR (125.7 MHz, acetone-d6/
DMSO-d6)
d 173.4 (6C]O), 170.5 (2C]O), 153.2, 138.9, 129.1, 128.4,
126.7,116.0 (PhC),101.5 (6C-2), 73.2 (6C-4, 6C-6), 66.4 (2PhOC), 64.4
(2CH2OC]O), 62.0 (2Cquat(CH2)3), 51.4 (2Cquat), 42.9 (6C-5), 17.5
(6CH3). HR ESI MS m/z calcd for C92H102Na2O30 866.3120; found
866. 3048.
(125.7 MHz, CDCl3)
d 173.4 (4C]O), 172.8 (2C]O), 153.0, 138,
129.0, 128.3, 126.3, 115.8 (PhC), 101.8 (C-2), 73.7, 73.6 (C-4, C-6),
66.3 (OCH2CH2O), 65.7 (4CH2O), 63.8 (OCH2CH2O), 47.0 (2Cquat),
42.7 (4Cquat), 17.9 (CH3). HR ESI MS m/z calcd for C68H78Na2O22
1269.4877; found 1269.4866.
4.4.12. 1,4-Bis-(2-(2,20,200-tris(2,20-bis(hydroxymethyl)propanoyloxy-
methyl)ethanoyloxy)-ethoxy)benzene (31). Using the general pro-
cedure for deprotection described above, 30 (1.50 g, 0.889 mmol),
dissolved in dry CH2Cl2 (30 mL), dry MeOH (15 mL), and dry THF
(15 mL) afforded 31 as a colorless crystalline solid (0.99 g, 96%
yield): mp 151e152 ꢀC; 1H NMR (500.13 MHz, DMSO-d6)
4.4.8. 1,4-Bis-(2-(2,20-bis(2,20-bis(hydroxymethyl)propanoyloxy-
methyl)propanoyloxy)-ethoxy)benzene (27). Using the general pro-
cedure for deprotection described above, 26 (1.95 g, 1.56 mmol)
dissolved in dry CH2Cl2 (15 mL), dry methanol (30 mL) and dry THF
(15 mL) afforded 27 as a colorless solid (1.36 g, 97% yield): mp
d
3.38e3.46 (m, 24H, 12CH2OH), 4.12 (t, J¼5 Hz, 4H, 2PhOCH2), 4.23
155e156 ꢀC; 1H NMR (500.13 MHz, methanol-d4)
d
1.12 (s, 12H, 4CH3),
(s, 12H, 2Cquat(CH2)3), 4.37 (t, J¼5 Hz, 4H, 2CH2OC]O), 4.67 (t,
1.28 (s, 6H, CH3), 3.62 (m, 16H, CH2OH), 4.17 (br m, 4H, PhOCH2CH2),
4.27 (AB q, DnAB¼19 Hz, JAB¼11 Hz, 8H, 4CH2OC]O), 4.43 (br m, 4H,
J¼5.5 Hz, 12H, 12OH), 6.87 (s, 4H, PhH); 13C NMR (125.7 MHz,
DMSO-d6)
d 174.0 (6C]O), 170.2 (2C]O), 152.5, 115.6 (PhC), 65.9