ꢀ-Methyl-2-amino-2,3-desoxyribofuranoside
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extracted three times with ethyl acetate, the organic phase was washed with brine, dried over NaSO4,
and the solvent removed in vacuo yielding 6.9 g of 11 (97%) as a yellowish syrup which crystallized
after standing at rt for a few days. Mp 70–72ꢁC; 1H NMR (CDCl3, 200 MHz): ꢂ ¼ 9.64 (d, J ¼ 1.8 Hz,
H-5), 7.83–7.70 (m, 2Ar-H), 7.58–7.36 (m, 3Ar-H), 6.28 (d, J ¼ 6.3 Hz, NH), 5.04 (s, H-1), 4.64–4.51
(m, H-2, H-4), 3.45 (s, OCH3), 2.54 (dt, J ¼ 7.0 and 13.9 Hz, H-3), 2.16 (ddd, J ¼ 1.0, 8.8, and 13.9Hz,
1H, H-30) ppm; 13C NMR (CDCl3, 50MHz): ꢂ ¼ 202.00 (C-5), 167.43 (N–C¼O), 133.64 (Ar C-1),
131.74 (Ar C-4), 128.47 (Ar C-3,5), 126.96 (Ar C-2,6), 108.65 (C-1), 81.38 (C-4), 55.64 (OCH3),
55.16 (C-2), 30.80 (C-3) ppm.
ꢀ-Methyl-2-benzoylamino-2,3-didesoxy-D-ribofuranoside (12, C13H17NO4)
Aldehyde 11 (1.6g, 6.4 mmol) was dissolved in 30cm3 of ethanol and 250 mg of sodium borohydride
(6.6mmol) were added. After 3 h of stirring at 20ꢁC the solvent was evaporated and the residue was
dissolved in ethyl acetate. The organic phase was washed with H2O and brine, dried over NaSO4, and
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the solvent was removed yielding 1.38 g of 12 (86%) as a pale syrup. H NMR (CDCl3, 200MHz):
ꢂ ¼ 7.73 (d, J ¼ 7.2 Hz, Ar-H-2,6), 7.41 (dd, Ar-H-3,4,5), 6.52 (d, J ¼ 6.9 Hz, NH), 4.88 (s, H-1), 4.57
(t, J ¼ 6.9 Hz, H-2), 4.47 (m, H-4), 3.72 (bd, J ¼ 11.5Hz, H-5), 3.52 (dd, J ¼ 5.8 and 11.5Hz, H-50),
3.39 (s, OCH3), 2.63 (bs, OH), 2.31 (ddd, J ¼ 1.5, 6.8, and 13.6Hz, H-3), 1.94 (ddd, J ¼ 0.9, 6.8, and
13.6Hz, H-30) ppm; 13C NMR (CDCl3, 50MHz): ꢂ ¼ 167.59 (N–C¼O), 133.69 (Ar C-1), 131.33 (Ar
C-4), 128.13 (Ar C-3,5), 126.90 (Ar C-2,6), 107.81 (C-1), 80.15 (C-4), 65.28 (C-5), 56.07 (C-2), 54.55
(OCH3), 30.59 (C-3) ppm.
ꢀ-Methyl-5-benzoyl-2-benzoylamino-2,3-didesoxy-D-ribofuranoside (13, C20H21NO5)
To a solution of 1 g of 12 (3.98 mmol) in dry pyridine, cooled to 0ꢁC, 750 mg of benzoic acid chloride
(5.34 mmol) were added. The mixture was allowed to reach rt and was stirred for 17h. After removal
of solvent in vacuo, the residue was purified by flash chromatography (petrol ether:ethyl acetate¼ 2:1).
After unreacted benzoic acid chloride, the desired product 13 eluted. Drying of the appropriate
1
fractions afforded 1.04g of 13 (74%) as a pale yellow syrup. H NMR (CDCl3, 200 MHz): ꢂ ¼ 8.08
(dd, J ¼ 1.4 and 6.9 Hz, Ar-H-2,6; benzylester), 7.75 (dd, J ¼ 1.5 and 6.6Hz, Ar-H-2,6; benzylamide),
7.61–7.36 (m, 6Ar-H), 6.36 (d, J ¼ 7.3 Hz, NH), 4.95 (s, H-1), 4.65 (m, H-2, H-4), 4.44 (dd, J ¼ 4.0
and 11.5Hz, H-5), 4.32 (dd, J ¼ 6.8 Hz, H-50), 3.37 (s, OCH3), 2.33 (ddd, J ¼ 6.1, 8.9, and 13.4Hz, H-
3), 2.13 (dd, J ¼ 7.4 Hz, H-30) ppm; 13C NMR (CDCl3, 50 MHz): ꢂ ¼ 167.33 (N–C¼O), 166.27 (O–
C¼O), 133.86 (Ar-C-1; benzylamide), 133.02 (Ar-C-4; benzylester), 131.56 (Ar-C-4; benzylamide),
129.76 (Ar-C-1; benzylester), 129.55 (Ar-C-2,6; benzylester), 128.34 und 128.27 (Ar-C-3,5; ben-
zylester and benzylamide), 126.95 (Ar-C-2,6; benzylamide), 107.90 (C-1), 76.76 (C-4), 67.58 (C-5),
55.94 (C-2), 54.47 (OCH3), 32.13 (C-3) ppm.
ꢀ-Methyl-2-benzylamino-2,3-didesoxy-D-ribofuranoside (14, C13H19NO3)
Aldehyde 11 (400mg, 1.6 mmol) was dissolved in 3.5 cm3 of a 1 M solution of LiAlH4 in THF and the
mixture was refluxed under Ar for 17 h. The reaction was quenched by dropwise addition of H2O until
no more H2 evolved. Ethyl acetate was added and the precipitated Al2O3 was filtered off and washed
with ethyl acetate. Evaporation of the organic solvents gave 340 mg of 14 (90%) as a yellowish syrup.
1H NMR (CDCl3, 200 MHz): ꢂ ¼ 7.31 (bs, 3Ar-H), 4.81 (s, H-1), 4.48 (ddt, J ¼ 2.8, 4.6, and 7.5 Hz, H-
4), 3.80 (s, PhCH2), 3.72 (dd, J ¼ 2.8 and 11.7 Hz, H-5), 3.47 (dd, J ¼ 4.6 and 11.8Hz, H-50), 3.37 (s,
OCH3), 3.33 (dd, J ¼ 2.2 and 6.6 Hz, H-2), 2.14 (ddd, J ¼ 6.6, 7.5, and 13.1Hz, H-3), 1.81 (ddd,
J ¼ 2.1, 7.5, and 13.1Hz, H-30) ppm; 13C NMR (CDCl3, 50MHz): ꢂ ¼ 139.57 (Ar C-1), 128.36 and
128.04 (Ar C-3,5 and Ar C-2,6), 127.05 (Ar C-4), 108.56 (C-1), 80.41 (C-4), 65.32 (C-5), 63.73 (C-2),
54.88 (OCH3), 51.92 (PhCH2), 31.41 (C-3) ppm.