492
A. S. Norgren et al.
PAPER
both 220 nm and 280 nm. The products were separated on a Phe-
nomenex Jupiter C-18 column (250 × 4.60 mm, 5 mm) with a linear
gradient of MeCN–H2O containing a small amount of TFA (either
A: H2O–MeCN–TFA, 95:5:0.1; B: MeCN–H2O–TFA, 95:5:0.1 or
A: H2O–MeCN–TFA, 98:2:0.05; B: MeCN–H2O–TFA, 98:2:0.05).
Preparative RP-HPLC was also performed on a Thermo Separation
Products instrument with a P4000 pump, a SN4000 signal convert-
er, and a UV1000 UV detector set to 220 nm. The products were
separated on a Phenomenex Jupiter C-18 column (250 × 21.20 mm,
10 mm) with a linear gradient of MeCN–H2O containing a small
amount of TFA (either A: H2O–MeCN–TFA, 95:5:0.1; B: MeCN–
H2O–TFA, 95:5:0.1 or A: H2O–MeCN–TFA, 98:2:0.05; B: MeCN–
H2O–TFA, 98:2:0.05). NMR measurements were done at ambient
temperature using the residual solvent signal (DMSO-d6) or the
TMS signal (CDCl3) as internal reference.
DIPEA (8.00 mmol, 1.40 mL) was added to the mixture. After ca. 5
min, a yellow-green solution was obtained and left to stir overnight
at r.t.. The mixture was then diluted with CH2Cl2 (30 mL) and
washed with dil HCl (pH 1–2). The aqueous phase was extracted
with CH2Cl2 (3 × 20 mL) and the combined organic phases were
dried (Na2SO4). Flash column chromatography (CH2Cl2–MeOH–
AcOH, 97:2.5:0.5) followed by lyophilization to remove traces of
AcOH gave 7 as a white fluffy material (3.40 mmol, 2.40 g, 86%);
21
[a]D –15.1 (c = 1.0, CH2Cl2); Rf = 0.40 (CH2Cl2–MeOH–AcOH,
95:4:1).
IR (KBr): 3472 (w), 2970 (w), 1757 (s), 1557 (w), 1541 (w), 1454
(m), 1428 cm–1 (m).
MS: m/z calcd for C34H36N4O13: 708.23; found: 709.38 [M + H],
731.33 [M + Na], 747.34 [M + K].
1
The H and 13C NMR spectra of 7 showed the presence of two
H-N-(Propargyl)Gly-OEt (2)
rotamers, hence the Fmoc group was cleaved in order to assign the
structure. The NMR data given below correspond to Fmoc-
deprotected 7.
Ethyl bromoacetate (100 mmol, 11.1 mL) in THF (30.0 mL) was
added dropwise to a cooled (ice-bath) solution of propargylamine
(100 mmol, 6.86 mL) and Et3N (200 mmol, 27.9 mL) in anhyd THF
(30.0 mL). The ice-bath was kept for 30 min before the reaction
mixture was allowed to attain r.t. After stirring overnight, the mix-
ture was filtered to remove ethylamine hydrobromide. The filtrate
was washed repeatedly with Et2O and the organic phase was re-
moved under reduced pressure. The crude 2 (84.0 mmol, 11.9 g) did
not require further purification before the next step.
1H NMR (500 MHz, CDCl3): d = 4.20 (q, J = 7.1 Hz, 2 H), 3.51 (s,
2 H), 3.49 (d, J = 2.4 Hz, 2 H), 2.24 (m, 1 H), 1.29 (t, J = 7.1 Hz, 3
H).
13C NMR (125 MHz, CDCl3): d = 171.9, 81.2, 72.0, 60.9, 49.2, 37.7,
14.2.
N-[1-(2,3,4,6-Tetra-O-acetyl-b-D-galactopyranosyl)-1H-1,2,3-
triazol-4-ylmethyl]glycine
1H NMR (500 MHz, CDCl3): d = 8.29 (s, 1 H), 5.90 (d, J = 9.4 Hz,
1 H), 5.57 (d, J = 3.1 Hz, 1 H), 5.52 (dd, J = 9.4, 9.4 Hz, 1 H), 5.31
(dd, J = 10.7, 3.1 Hz, 1 H), 4.57 (m, 2 H), 4.31 (dd, J = 6.3, 6.3 Hz,
1 H), 4.19 (d, J = 6.3 Hz, 2 H), 3.91 (m, 2 H), 2.22 (s, 3 H), 2.05 (s,
3 H), 2.03 (s, 3 H), 1.88 (s, 3 H).
13C NMR (125 MHz, CDCl3): d = 170.5, 170.2, 169.9, 169.6, 169.4,
138.2, 125.0, 86.3, 74.0, 70.5, 68.3, 66.6, 61.0, 46.9, 41.4, 20.6,
20.5, 20.4, 20.0.
N-(9-Fluorenylmethoxycarbonyl)-N-[1-(2,3,4,6-tetra-O-acetyl-
a-D-galactopyranosyl)-1H-1,2,3-triazol-4-ylmethyl]glycine (8)
Triazole 8 was synthesized according to the procedure and on the
same scale (4.00 mmol) as compound 7 using carbohydrate 5 as the
azide building block, giving 8 as a white fluffy material (3.00 mmol,
N-(9-Fluorenylmethoxycarbonyl)-N-(propargyl)glycine (3)
Aq 4 M NaOH (20.0 mL) was added to a solution of 2 (84.0 mmol,
11.9 g) in dioxane (100 mL) and MeOH (35.0 mL). After stirring for
40 min, the reaction mixture was concentrated in vacuo. The result-
ing sodium salt was dissolved in H2O (80.0 mL) and the pH was ad-
justed to 9–9.5 with concd HCl. A solution of Fmoc-OSu (84.0
mmol, 28.3 g) in MeCN (130 mL) was subsequently added and the
mixture was left to stir overnight at r.t.. The MeCN was removed
under reduced pressure and the aqueous phase was acidified (pH 1–
2) with concd HCl. The aqueous phase was extracted with CH2Cl2
(2 × 100 mL) and the combined organic phases were washed with
H2O (50 mL) and brine (50 mL), dried (Na2SO4) and concentrated
under reduced pressure. Recrystallization from EtOAc–hexane
gave 3 as white crystals in 82% yield (66.0 mmol, 22.1 g); mp 130–
132 °C; Rf = 0.33 (CH2Cl2–MeOH–AcOH, 97:2.5:0.5).
21
2.12 g, 75%); [a]D +58.5 (c = 1.0, CH2Cl2); Rf = 0.45 (CH2Cl2–
MeOH–AcOH, 95:4:1).
IR (KBr): 3476 (w), 2974 (w), 1756 (s), 1560 (w), 1538 (w), 1452
(m), 1427 cm–1 (m).
MS: m/z calcd for C34H36N4O13: 708.23; found: 709.63 [M + H],
731.65 [M + Na].
1
The H and 13C NMR spectra of 8 showed the presence of two
rotamers, hence the Fmoc group was cleaved in order to assign the
structure. The NMR data given below correspond to Fmoc-
deprotected 8.
1
In the H NMR spectrum of 3 only one major conformer was ob-
N-[1-(2,3,4,6-Tetra-O-acetyl-a-D-galactopyranosyl)-1H-1,2,3-
triazol-4-ylmethyl]glycine
served. In the 13C NMR spectra, however, the existence of rotamers
was observed as either double sets of peaks or broad signals.
1H NMR (500 MHz, CDCl3): d = 8.20 (s, 1 H), 6.51 (d, J = 6.3 Hz,
1 H), 6.12 (dd, J = 10.7, 3.1 Hz, 1 H), 5.69 (d, J = 2.5 Hz, 1 H), 5.60
(dd, J = 10.7, 5.7 Hz, 1 H), 4.61 (dd, J = 6.3, 6.3 Hz, 1 H) 4.58 (m,
2 H), 4.16–4.05 (m, 2 H), 3.99 (br s, 2 H), 2.22 (s, 3 H), 2.02 (s, 3
H), 1.99 (s, 3 H), 1.87 (s, 3 H).
IR (KBr): 3851 (s), 2959 (w), 2893 (w), 1736 (s), 1678 (s), 1541
(w). 1479 (m), 1460 (m), 1403 cm–1 (m).
1H NMR (500 MHz, DMSO-d6): d = 12.87 (s, 1 H), 7.89 (m, 2 H),
7.72 (m, 1 H), 7.60 (m, 1 H), 7.35 (m, 4 H), 4.30–4.00 (m, 7 H), 3.30
(m, 1 H).
13C NMR (125 MHz, DMSO-d6): d = 170.99/170.87, 155.48/
155.45, 144.1, 141.19/141.15, 128.2, 127.6, 125.75/125.56, 120.6,
79.76/79.57, 68.0 (br), 48.33/47.72, 46.98/46.89, 37.63/37.45.
13C NMR (125 MHz, CDCl3): d = 170.6, 170.4, 170.1, 170.0, 169.4,
137.3, 128.0, 82.6, 70.6, 67.5, 67.5, 66.5, 61.1, 47.4, 41.4, 20.6,
20.6, 20.6, 20.1.
N-(9-Fluorenylmethoxycarbonyl)-N-[1-(2-acetamido-3,4,6-tri-
O-acetyl-2-deoxy-b-D-glucopyranosyl)-1H-1,2,3-triazol-4-yl-
methyl]glycine (9)
Triazole 9 was synthesized in 2.80 mmol scale according to the
same procedure as compound 7 using carbohydrate 6 as azide build-
ing block, giving 9 as a white fluffy material (2.10 mmol, 1.49 g,
N-(9-Fluorenylmethoxycarbonyl)-N-[1-(2,3,4,6-tetra-O-acetyl-
b-D-galactopyranosyl)-1H-1,2,3-triazol-4-ylmethyl]glycine (7);
Typical Procedure
Azide 4 (4.00 mmol, 1.49 g) and the acetylene 3 (4.00 mmol, 1.34
g) were mixed with CuI (4.00 mmol, 0.76 g) and sodium ascorbate
(4.00 mmol, 0.79 g), and dissolved in anhyd CH2Cl2 (20 mL).
Synthesis 2009, No. 3, 488–494 © Thieme Stuttgart · New York