CHEM01200604012 Dibakar Goswami - Homi Bhabha National ...

The organic extracts were washed with aqueous HCl, water and brine, and dried. Solvent
removal in vacuo and chromatographic purification (silica gel, 0-15% EtOAc/Hexane) of
the crude residue afforded pure 165. Yield: 1.14 g (91.1%); colourless oil; [α] 25 D +32.8 (c
3.2, CHCl3); IR: 1168, 1103 cm -1 ; 1 H NMR: δ 1.4-1.6 (m, 10H), 2.39 (s, 3H), 2.78 (q, J =
7.2 Hz, 1H), 3.10 (dd, J = 13.8, 6.4 Hz, 1H), 3.7-3.9 (m, 2H), 4.2 (m, 1H), 4.6 (m, 1H),
7.04-7.25 (m, 7H), 7.58 (d, J= 8.2 Hz, 2H); 13 C NMR: δ 21.3, 23.5, 23.6, 24.9, 34.2, 35.4,
36.5, 64.4, 74.1, 82.1, 110.0, 126.4, 127.4, 128.2, 129.3, 129.4, 133.3, 135.5, 144.2. Anal.
Calcd. for C 23 H 28 O 5 S: C, 66.32; H, 6.72; S, 7.69%. Found: C, 66.14; H, 6.65; S, 7.89%.
(2S, 3R)- 2-Azido -1-phenyl-butane-3,4-diol 166. A mixture of 165 (0.832 g, 2.0 mmol)
in CH 2 Cl 2 (40 mL) and 80% aqueous TFA (10 mL) was stirred for 3 h at 0 °C. The mixture
was diluted with water (15 mL) and extracted with CHCl 3 (30 mL), the organic layer
separated and the aqueous layer extracted with CHCl 3 (10 mL). The combined organic
extracts were washed successively with aqueous 2% NaHCO 3 , H 2 O and brine, and dried.
Solvent removal in vacuo followed by column chromatography of the residue (silica gel, 0-
5% MeOH/CHCl 3 ) furnished pure 166. Yield: 0.308 g (74.1%); white solid; mp 80-81 o C
[lit. 32b mp 80-82 o C]; [α] 25 D +30.2 (c 1.8, CHCl 3 ) [lit. 32b [α] 25 D +30.6 (c 2.0, CHCl 3
)]; IR:
3397, 2112 cm -1 ; 1 H NMR: δ 1.26 (broad s, 2H), 2.72-2.83 (m, 1H), 2.92-3.09 (m, 1H),
3.6-3.8 (m, 4H), 7.29 (m, 5H); 13 C NMR: δ 36.9, 63.1, 65.5, 73.0, 126.9, 128.6, 129.2,
137.2.
2S-[1(S)-Azido-2-phenylethyl]oxirane (VI). To a cooled (0 o C) and stirred solution of
compound 166 (0.207 g, 1.0 mmol) in pyridine (4 mL) was dropwise added a solution of p-
TsCl (0.20 g, 1.05 mmol) in pyridine (5 mL) and the solution stirred for 3 h (cf. TLC).
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