688
Lalthazuala Rokhum and Ghanashyam Bez
2.1 Typical procedure for synthesis of azide
from alcohol
δ 65.59, 48.56, 37.59, 23.74; ESI-MS: m/z 137.0
(M+ Na).
A mixture of stearyl alcohol (0.810 g, 3 mmol), triphe-
nylphosphine (0.943 g, 3.6 mmol) and iodine (0.914 g,
3.6 mmol) was ground with a pestle in a mortar for
10 min, when exothermic reaction took place to make
a paste. Then a solution of sodium azide (0.780 g,
12 mmol) in DMSO was added and stirred for 30 min.
Upon completion of the reaction, ice-cooled solution of
sodium thiosulphate (50 mL) was added and extracted
with diethyl ether (3×30 mL). The combined organic
layer was washed with brine (50 mL), dried over an-
hydrous Na2SO4 and concentrated under vacuum to get
the crude product, which was purified by column chro-
matography using 5% ethyl acetate in hexane as eluent
to get the product in 85% (0.752 g, 2.55 mmol) yields.
2.2e 1-(1-Azido-1-phenylmethyl)-4-chlorobenzene:
Colourless liquid; IR (KBr): ν 3018, 2925, 2625,
2667, 2408, 2103, 1507, 1434, 1215, 1096, 1023,
930, 764, 671 cm−1; 1HNMR (400 MHz, CDCl3):
δ 7.29–7.16 (m, 9H), 5.61(s,1H); 13CNMR (100 Hz,
CDCl3): δ 139.11, 138.15, 133.91, 128.87, 128.85,
128.70, 128.32, 127.37, 67.81; ESI-MS: m/z 266.1
(M+ Na), 268.1 (M+ Na).
2.2f Citronellyl azide: Colourless oil; IR (KBr): ν
3018, 2925, 2402, 2097, 1520, 1460, 1387, 1215,
1029, 930, 758, 671 cm−1; 1HNMR (400 MHz, CDCl3):
δ 5.01 (t, J = 6.4 Hz, 1H), 3.22 (m, 2H), 1.77 (q, 2H),
1.61 (s, 3H), 1.53 (s, 3H), 1.38–1.08 (m,7H), 0.84 (d,
J = 6.8 Hz, 3H); 13CNMR (100 Hz, CDCl3): δ 131.50,
124.41, 49.50, 36.84, 35.62, 29.95, 25.71, 25.36, 19.22,
17.65; ESI-MS: m/z 204.1 (M+ Na).
2.2 Spectroscopic data of the new compounds
2.2a 1-(1-Azidoethyl)-3-bromobenzene: Colourless
liquid; IR (KBr): ν 3018, 2402, 2110, 1527, 1487,
1434, 1215, 1076, 1016, 930, 764, 671, 506 cm−1;
1HNMR (400 MHz, CDCl3): δ 7.44 (d, J = 8 Hz, 2H),
7.12(d, J = 8 Hz, 2H), 4.23 (s, 2H); 13CNMR (100 Hz,
CDCl3): δ 134.37, 131.99, 129.81, 122.34, 54.08;
ESI-MS: m/z 234.0 (M+ Na), 236.0 (M+ Na).
2.2g 1-Azido-4-tert-Butyldimethylsilyloxybutane:
Colourless liquid; IR (KBr): ν 3343, 3012, 2402, 2103,
1977, 1904, 1825, 1725, 1600, 1434, 1374, 1215, 1116,
1
1043, 930, 758, 545, 543 cm−1; HNMR (400 MHz,
CDCl3): δ 3.58 (t, J = 6 Hz, 2H), 3.24 (t, J = 6.8 Hz,
2H), 1.64- 1.20 (m, 6H), 0.84 (s, 9H), 0.00 (s, 6H);
13CNMR (100 Hz, CDCl3) : δ 62.44, 51.37, 29.84,
25.91, 25.50, −5.34; ESI-MS: m/z 252.0 (M+ Na).
2.2b Stearyl azide: Colourless liquid; IR (KBr): ν
1
2103, 2870-2950 cm−1; H NMR (400 MHz, CDCl3):
δ 0.87 (t, J = 7.2 Hz, 3H), 1.25 (m, 30H), 1.58 (m, 2H),
3.25 (t, J = 6.8 Hz, 2H); 13C NMR (75 MHz, CDCl3):
δ 14.53, 23.13, 27.14, 29.27, 29.61, 29.82, 29.93, 30.00,
30.08, 30.12, 30.14, 32.37, 51.86; MS: m/z 318.2 [M+].
2.2h 1-Azido-4-tetrahydropyranyloxybutane:
Colourless liquid; IR (KBr): ν 3018, 2945, 2402, 2103,
1520, 1460, 1215, 1029, 930, 764, 671 cm−1; HNMR
1
(400 MHz, CDCl3): δ 4.49 (t, J = 4.4 Hz, 1H), 3.79–
3.66 (m, 2H), 3.43–3.30 (m, 2H), 3.23 (t, J = 6.4 Hz,
2H), 1.75–1.42 (m, 10H); 13CNMR (100 Hz, CDCl3):
δ 98.87, 66.79, 62.35, 51.32, 30.68, 26.89, 25.93,
25.42, 19.59; ESI-MS: m/z 222.2 (M+ Na).
2.2c 4-Azido-2-methylpentan-2-ol: Colourless liq-
uid; IR (KBr): ν 3025, 2402, 2110, 1898, 1725, 1600,
1527, 1434, 1381, 1222, 1122, 1043, 930, 758, 678,
1
545, 446 cm−1; HNMR (400 MHz, CDCl3) : δ 3.69
(m, 1H), 1.97 (s, 1H, -OH), 1.6 (dd, J = 14.8, 10 Hz,
2H), 1.49 (dd, J = 14.8, 3.2 Hz, 2H), 1.28 (s, 3H),
1.26 (s, 3H); 13CNMR (100 Hz, CDCl3): δ 70.15,
54.51, 48.20, 30.15, 29.80, 20.43; ESI-MS: m/z 166.1
(M+ Na).
3. Results and discussion
Our recent interest in the catalytic application of
iodine13 opened up the idea that if triphenylphos-
phine and iodine is mixed together, the resulting phos-
phonium salt can act as an excellent hydroxy group
activator. Since iodine is a cheap solid reagent and oper-
ational friendly, we envisaged that the use of iodine
would facilitate further simplification of the protocol.
Moreover, unreacted triphenylphosphine should sit with
the triphenylphosphine oxide as iodotriphenylphospho-
nium iodide, thereby making the purification process
2.2d 4-Azidobutan-2-ol: Colourless liquid; IR
(KBr): ν 3608, 3429, 3025, 2965, 2402, 2342, 2103,
1725, 1606, 1507, 1447, 1387, 1222, 1122, 1049, 923,
1
764, 671 cm−1; HNMR (400 MHz, CDCl3) : δ 3.88
(m, 1H), 3.35 (m, 1H), 1.87 (s, 1H, -OH), 1.65 (m, 2H),
1.17 (d, J = 6 Hz, 3 H); 13CNMR (100 Hz, CDCl3):