L. V. R. Reddy et al. / Tetrahedron: Asymmetry 18 (2007) 542–546
545
60.01 g) and stirred at 120 ꢁC for 3 days. DMF was re-
moved under reduced pressure, and the reaction mixture
washed with H2O and the aqueous phase was re-extracted
with EtOAc (3 · 15 mL) until TLC showed no traces of
azide. The combined organic phases were dried over anhy-
drous Na2SO4 and evaporated to yield 2 (269 mg, 62%) as a
syrup; [a]D = +47.8 (c 0.138, CHCl3); Rf 0.73 (3/7 EtOAc/
hexane); IR (neat, cmꢀ1): 2934, 2105, 1596, 1457, 1352; 1H
NMR (300 MHz, CDCl3): d 1.38 (s, 3H, CH3), 1.44 (s, 3H,
CH3), 3.83 (td, 1H, J = 4.6, 7.3 Hz), 3.90–4.02 (m, 4H),
4.10 (dd, 1H, J = 6.3, 8.5 Hz), 4.22 (t, 1H, J = 4.2 Hz),
4.37 (dd, 1H, J = 6.2, 13.3 Hz), 4.76 (d, 1H, J = 11.2 Hz,
CH2Ph), 4.84 (d, 1H, J = 11.2 Hz, CH2Ph), 7.33–7.46 (m,
5H, ArH); 13C NMR (75 MHz, CDCl3): d 25.7 (CH3),
27.1 (CH3), 61.8 (CH), 67.3 (CH2), 69.0 (CH2), 73.8
(CH), 74.6 (CH2), 79.8 (CH), 82.5 (CH), 109.3 (qC),
128.3 (ArC), 128.5 (ArC), 128.7 (ArC), 137.9 (Ar qC) mass
(ESI-MS) m/z 319; found 342 [M+Na]+ꢀ.
trated. Purification of the resulting residue by CHCl3/
MeOH/aq NH4OH (89:10:1) as eluent afforded target com-
pound 1 as an offwhite amorphous solid (28 mg, 72%).
[a]D = +13.3 (c 0.03, EtOH), [a]D = +8.5 (c 0.047, MeOH),
22
{lit.9 [a]D = +18 (c 0.1, EtOH), lit.12d ½aꢁD ¼ þ4:8 (c 1.0,
MeOH)}; Rf 0.18 (3/17 MeOH/CHCl3); IR (KBr, cmꢀ1):
1
2916, 2848, 1654, 1631, 1583, 1070, 831, 719; H NMR
(300 MHz, CD3OD): d 0.89 (t, 3H, J = 6.8 Hz), 1.28 (br
s, 24H), 1.61–1.63 (m, 2H), 3.49–3.69 (m, 2H), 3.73–3.78
(m, 1H), 3.92 (qt, 1H), 4.01–4.03 (m, 1H); 13C NMR
(75 MHz, CDCl3/CD3OD) d 14.5, 23.1, 26.5, 29.1, 29.3,
29.7, 30.1, 32.3, 34.0, 54.4, 70.5, 71.3, 83.5; mass (EI-MS)
m/z 299, found 299 [M]+ꢀ, 300 [M+1]+ꢀ. EI-HRMS: calcd
for C18H37NO2, 299.2824, measured 299.2824, error, 0.0
(mmu).
Acknowledgements
4.1.3. Synthesis of olefin 9. A solution of azide acetonide 2
(130 mg, 0.40 mmol) and periodic acid (112 mg,
0.49 mmol) in 15 mL of dry ethyl acetate was allowed to
stir for 1.5 h, then filtration and evaporation under reduced
pressure afforded a colorless syrup of aldehyde 8 (>98%
pure from NMR) which was immediately used in the next
step.
This research project was funded by ICMR (Ref: IRIS
Cell No. 200-02220), New Delhi. We are thankful to
Sophisticated Analytical Instrumentation Facility, CDRI,
for providing spectral data and Mr. A. K. Pandey for
technical assistance. L.V.R.R. and P.V.R. thank CSIR,
for providing fellowships.
Compound 8; 1H NMR (300 MHz, CDCl3) d 3.98–4.08 (m,
3H), 4.29 (dd, 1H, J = 2.4, 7.2 Hz), 4.50 (dd, 1H, J = 4.5,
6.9 Hz), 4.66, 4.71 (2d, 2H, J = 11.7 Hz, CH2Ph), 7.33–
7.39 (m, 5H, ArH), 9.66 (br d, 1H, J = 4.5 Hz); 13C
NMR (75 MHz, CDCl3) d 61.4 (CH), 70.8 (CH2), 74.1
(CH2), 81.8 (CH), 82.8 (CH), 128.3 (ArC), 128.6 (ArC),
128.9 (ArC), 136.9 (Ar qC), 200.4 (ald).
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1
1460 1350; H NMR (300 MHz, CDCl3): d 0.88 (t, 3H,
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4.1.4. Synthesis of pachastrissamine 1 (jaspine B). A mix-
ture of compounds 9 (55 mg, 0.13 mmol), ammonium for-
mate (420 mg, 6.65 mmol), and 10% Pd/C (20 mg) in
dried MeOH (10 mL) was stirred under an Ar atmosphere
at reflux for 18 h. The mixture was filtered and concen-