B. N. Manjunath, N. P. Sane, I. S. Aidhen
FULL PAPER
gel column chromatography with ethyl acetate/hexane (2:5) as elu-
ent. The pure product was obtained as a white solid (2.0 g, 75%
yield). Rf = 0.27 (EtOAc/hexane, 1:1) M.p. 128 °C. 1H NMR
(CDCl3/TMS, 400 MHz): δ = 3.18 (s, 3 H), 3.79 (s, 3 H), 4.80 (s, 2
4.64 (d, J = 3.7 Hz), 4.84–4.87 (m, 1 H), 6.01 (d, J = 3.8 Hz, 1 H),
6.77 (d, J = 16.0 Hz, 1 H), 6.99–7.05 (dd, J = 5.7, 16.0 Hz, 1 H),
7.27–7.35 (m, 5 H) ppm. 13C NMR (CDCl3/TMS, 100 MHz): δ =
26.2, 26.8, 32.4, 61.8, 72.3, 79.8, 82.8, 104.9, 111.8, 120.7, 127.8,
H), 7.49–7.65 (m, 2 H), 7.99 (d, J = 8.0 Hz, 1 H), 8.20 (d, J = 127.9, 128.5, 137.2, 139.7, 166.1 ppm. HRMS (ES): calcd. for
8.0 Hz, 1 H) ppm. 13C NMR (CDCl3/TMS, 100 MHz): δ = 32.1, C19H25NO6 [M+H]+ 364.1760; found 364.1739.
56.4, 61.9, 122.4, 125.5, 127.6, 128.0, 137.1, 152.5, 161.5,
(E)-N-Methoxy-N-methyl-[methyl-5,6-dideoxy-2,3-O-(1-methyl-
ethylidene)-β- -ribo-hept-5-enofuranosid]uronamide (7j): Yield 53%.
165.6 ppm. HRMS (ES): calcd. for C11H12N2S2O4 [M+H]+
301.0238; found 301.0330. C11H12N2S2O4 (300.36): calcd. C 43.99,
H 4.03, N 9.33; found C 44.30, H 4.15, N 8.90.
D
[α]2D5 = –17.60 (c = 1, CHCl3); Rf = 0.24 (EtOAc/hexane, 1:2). IR
2937, 1668, 1635, 1384 cm–1. 1H NMR (CDCl3/TMS, 400 MHz): δ
= 1.33 (s, 3 H), 1.51 (s, 3 H), 3.25 (s, 3 H), 3.38 (s, 3 H), 3.71(s, 3
H), 4.59–4.64 (m, 1 H), 4.70 (d, J = 5.0 Hz, 1 H), 4.83 (d, J =
5.7 Hz, 1 H), 5.04 (s, 1 H), 6.59 (d, J = 15.0 Hz, 1 H), 6.89–6.95 (dd,
J = 5.7, 15.0 Hz, 1 H) ppm. 13C NMR (CDCl3/TMS, 100 MHz): δ
= 25.1, 26.5, 55.0, 32.3, 61.8, 85.2, 85.4, 86.7, 109.8,112.7, 120.2,
144.4,165.9 ppm. HRMS (ES): calcd. for C13H21NO6 [M+H]+
288.1447; found 288.1464.
A Representative Procedure for the Reaction of the Aldehyde with
the Reagent 2: A solution of sulfone 2 (0.155 g, 0.52 mmol) in dry
THF (5 mL) was added to oil-free sodium hydride (0.016 g,
0.65 mmol) under an inert atmosphere and stirred for 2 min at
room temperature. To this reaction mixture was added a solution
of aldehyde 6h (0.100 g, 0.43 mmol) dissolved in dry THF (2 mL).
The stirring was continued for a further 24 hr. On completion of
the reaction, which was indicated by TLC, THF was removed un-
der reduced pressure. To the residue was added ammonium chlo-
ride (5 mL, 20% solution), and the product was extracted with di-
ethyl ether (3×5 mL). The combined ether extract was washed with
an ice-cold aqueous solution of sodium hydroxide (10 mL, 20%).
On evaporation of the ether layer after drying over sodium sulfate,
the crude product was obtained and was subjected to column
chromatography on silica gel (hexane/ethyl acetate, 8:2) to furnish
compound 7h as a colorless syrup (0.099 g, 72%).
Acknowledgments
We thank CSIR New Delhi for the funding of the new project in
the year 2005 [01(1971)/05/EMR-II]. We thank DST New Delhi,
for the funding towards a 400 MHz NMR machine under the IR-
PHA Scheme and a ESI-MS facility under the DST-FIST program.
B. N. M. is thankful to the University Grants Commission for a
Junior Research Fellowship.
(E)-3-[5-(tert-Butyl-dimethyl-silanyloxymethyl)furan-2-yl]-N-meth-
oxy-N-methylpropenamide (7f): Yield 59%. Rf = 0.20 (EtOAc/hex-
ane, 1:5). IR 3119, 2955, 2931, 1657, 1618, 1584, 1381 cm–1. 1H
NMR (CDCl3/TMS, 400 MHz): δ = 0.06 (s, 3 H), 0.12 (s, 3 H),
0.93 (s, 9 H), 3.29 (s, 3 H), 3.75 (s, 3 H), 4.69 (s, 2 H), 6.3 (d, J =
3.6 Hz, 1 H), 6.53 (d, J = 3.6 Hz, 1 H), 6.89 (d, J = 15.0 Hz, 1 H),
7.44 (d, J = 15.0 Hz, 1 H) ppm. 13C NMR (CDCl3/TMS,100 MHz):
δ = –5.2, 18.4, 25.8, 58.4, 32.6, 61.9, 109.6, 113.0, 115.3, 130.0,
151.1, 156.4, 167.2 ppm. HRMS (ES): calcd. for C16H27SiNO4
[M+H]+ 326.1788; found 326.1795.
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3213–3214 and references cited therein; b) L. Blackburn, H.
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Am. Chem. Soc. 1990, 112, 7001.
(E)-N-Methoxy-N-methyl-2,3-dideoxy-4,5-isopropylidene-D-glycero-
pent-2-enamide (7g): Yield 50%. [α]2D5 = –1.22 (c = 1, CHCl3). Rf =
0.22 (EtOAc/hexane, 3:7). IR 2983, 2938, 1716, 1663, 1622,
1386 cm–1. 1H NMR (CDCl3/TMS, 400 MHz): δ = 1.35 (s, 3 H),
1.38 (s, 3 H), 3.18 (s, 3 H), 3.67 (s, 3 H), 4.12 (m, 2 H), 4.65 (m, 1
H), 6.62 (d, J = 15.0 Hz, 1 H), 6.82 (dd, J = 6.1 Hz, 15.0 Hz, 1 H)
ppm; 13CNMR (CDCl3/TMS, 100 MHz): δ = 25.7, 26.4, 32.3, 61.7,
68.8, 75.3, 109.9, 119.8, 143.2, 165.9 ppm. HRMS (ES): calcd. for
C10H17NO4 [M+H]+ 216.1236; found 216.1238.
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Lett. 1989, 30, 3779–3780; b) D. F. Netz, J. L. Seidel, Tetrahe-
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(E)-N-Methoxy-N-methyl-2,3-dideoxy-4,5:6,7-di-O-isopropylidene-
D
-arabino-hept-2-enamide (7h): Yield 73%. [α]2D5 =+8.97 (c = 1,
CHCl3); Rf = 0.25 (EtOAc/hexane, 1:5). IR 2986, 2928,1665, 1637,
1378 cm–1. 1H NMR (CDCl3/TMS, 400 MHz): δ = 1.35 (s, 3 H),
1.41 (s, 3 H), 1.43 (s, 3 H), 1.45 (s, 3 H), 3.26 (s, 3 H), 3.71 (s, 3
H), 3.73–3.75 (m, 1 H), 3.93–3.96 (m, 1 H), 4.11–4.15 (m,2 H),
4.58–4.61(m,1 H), 6.73 (d, J = 16 Hz, 1 H), 7.02 (dd, J = 16 Hz, 1
H) ppm. 13C NMR (CDCl3/TMS, 100 MHz): δ = 25.2, 26.7, 26.7,
26.9, 32.3, 61.7, 67.4, 76.9, 79.3, 81.2, 109.8, 109.9, 119.2, 143.6,
166.2 ppm. HRMS (ES): calcd. for C15H25NO6 [M + Na]+
338.1580; found 338.1567.
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is now available from Aldrich (Catalogue No: 56, 108–8).
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[13] Epimerization at the α-stereocenter in the aldehyde 6j was ob-
served during preparation by the Swern oxidation of the corre-
sponding alcohol. Product 7j was obtained in the same diaste-
reoisomeric ratio after reaction with the carbanion from 2. The
use of the Swern oxidation method became inevitable as the
(E)-N-Methoxy-N-methyl-3-O-benzyl-5,6-dideoxy-1,2-O-isopropyl-
idene-α-D =
-xylo-hept-5-enofuranuronamide (7i): Yield 56%. [α]2D5
–11.79 (c = 1, CHCl3); Rf = 0.3 (EtOAc/hexane, 3:7). IR 2984,
2937, 1667, 1634, 1384 cm–1. 1H NMR (CDCl3/TMS, 400 MHz): δ
= 1.33 (s, 3 H), 1.49 (s, 3 H), 3.26 (s, 3 H), 3.68 (s, 3 H), 3.99 (d, J
= 3.0 Hz, 1 H), 4.52 (d, J = 12 Hz, 1 H), 4.60 (d, J = 12 Hz, 1 H),
2854
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