N. M. T. Louren c¸ o, C. A. M. Afonso / Tetrahedron 59 (2003) 789–794
793
The reaction mixture was extracted with diethyl ether
2. (a) Welton, T. Chem. Rev. 1999, 99, 2071. (b) Wasserscheid,
P.; Keim, W. Angew. Chem. Int. Ed 2000, 39, 3772. (c) Dupont,
J.; Consorti, C. S.; Spencer, J. J. Braz. Chem. Soc. 2000, 11,
337. (d) Freemantle, M. Chem. Eng. News 2000, May 15, 37.
(e) Brennecke, J. F.; Maginn, E. J. AIChE J. 2001, 47, 2384.
3. Blanchard, L. A.; Hancu, D.; Beckman, E. J.; Brennecke, J. F.
Nature 1999, 28, 399.
(
MgSO , filtered and evaporated in vacuo. The obtained
5£3 mL) and the combined organic phases were dried over
4
1
residue showed by H NMR only the azide for entries 7, 10
and 11 and a mixture of azide and alkyl halide for entries 8
0
; H
(
bromo-acetophenone; IR (film): 2107, 1700, cm
98:2), 9 (80:20) and 12 (27:73), respectively; 2-azido-4 -
2
1
1
NMR (400 MHz, CDCl , 258C): d 7.78, (2H, d J¼8.4 Hz),
4. (a) Lau, R. M.; Van Rantwijk, F.; Seddon, K. R.; Sheldon,
R. A. Org. Lett. 2000, 2, 4189. (b) Sch o¨ fer, S. H.; Kaftzik, N.;
Wassercheid, P.; Kragl, U. Chem. Commun. 2001, 425.
(c) Kim, K.-W.; Song, B.; Choi, M.-Y.; Kim, M.-J. Org.
Lett. 2001, 3, 1507. (d) Nara, S. J.; Harjani, J. R.; Salunkhe,
M. M. Tetrahedron Lett. 2002, 43, 2979. (e) Lozano, P.; de
Diego, T.; Carri e´ , D.; Vaultier, M.; Iborra, J. L. Chem.
Commun. 2002, 692. (f) Reetz, M. T.; Wiesenh o¨ fer, W.;
Franci o` , G.; Leitner, W. Chem. Commun. 2002, 992.
3
7
.65 (2H, d J¼8.4 Hz), 4.53 (2H,s), unstable in pure form.
PhCHN Me,
3 3
1
29,30
29,31
Spectral data (IR and H NMR) of BnN
2
9
32
1-azido-octane and 2-azido-acetophenone identical to
those reported. For the formation of 2-azido-acetophenone
(entry 10), the reaction mixture was extracted (5£3 mL)
with different solvents giving the following yields: methyl
t-butyl ether (99%), di-iso-propyl ether (99%) and n-hexane
(
(
44%). In case of entry 13 was used sodium azide
653.9 mg, 2.0 eq.) in water (1.5 mL) and 2-bromoaceto-
5
. For recent reviews see: (a) Sheldon, R. Chem. Commun. 2001,
2399. (b) Gordon, C. M. Appl. Catal. A: General 2001, 222,
phenone (1.00 g, 5.0 mmol) in [bmim][PF ] (0.5 mL).
6
1
01. For other more recent examples see: (c) Handy, S. T.;
4
.7. Recycling assays
Zhang, X. Org. Lett. 2001, 3, 233. (d) Peng, J.; Deng, Y.
Tetrahedron Lett. 2001, 42, 403. (e) Wasserscheid, P.;
Waffenschmidt, H.; Machnitzki, P.; Kottsieper, K. W.; Stelzer,
O. Chem. Commun. 2001, 451. (f) Rosa, J. N.; Afonso, C. A.
M.; Santos, A. G. Tetrahedron 2001, 57, 4189. (g) Branco,
L. C.; Afonso, C. A. M. Tetrahedron 2001, 57, 4405. (h) Cal o` ,
V.; Nacci, A.; Lopez, L.; Napola, A. Tetrahedron Lett. 2001,
Sodium azide (267 mg, 2.0 eq.) in water (4 mL) was added
to a vigorous stirred solution (approx. 1200 rpm) of
2
(
-bromo-acetophenone (400 mg, 2.1 mmol) in [bmim][PF6]
2 mL) at rt, in a glass vial of 20 mL. After 1.5 h (complete
reaction by TLC) the aqueous phase was removed using a
pipette and the remained ionic liquid phase was extracted
with diethyl ether (4£10 mL). The combined organic phases
4
2, 4701. (i) Peng, J.; Deng, Y. Tetrahedron Lett. 2001, 42,
917. (j) Hagiwara, H.; Shimizu, Y.; Hoshi, T.; Suzuki, T.;
5
were dried over MgSO , filtered, evaporated in vacuo and
4
Ando, M.; Ohkubo, K.; Yokoyama, C. Tetrahedron Lett. 2001,
2, 4349. (k) Morrison, D. W.; Forbes, D. C.; Davis, J. H.
the residue was passed through a small flash chromato-
graphy (pipette size, eluent: diethyl ether) to give 2-azido-
acetophenone; spectral data (IR and H NMR) identical to
the above sample. For the next cycle was added successively
2
and repeated the previous procedure. After 15 cycles the
4
Tetrahedron Lett. 2001, 42, 6053. (l) Dyson, P.; Ellis, D.;
Welton, T. Can. J. Chem. 2001, 79, 705. (m) Buijsman, R. C.;
van Vuuren, E.; Sterrenburg, J. G. Org. Lett. 2001, 3, 3785.
1
-bromo-acetophenone, a solution of sodium azide in water
(
n) Fraile, J. M.; Garcia, J. I.; Herreias, C. I.; Mayoral, J. A.;
Carri e´ , D.; Vaultier, M. Tetrahedron: Asymmetry 2001, 12,
1891. (o) Berger, A.; de Souza, R. F.; Delgado, M. R.; Dupont,
J. Tetrahedron: Asymmetry 2001, 12, 1825. (p) S e´ meril, D.;
Olivier-Bourbigou, H.; Bruneau, C.; Dixneuf, P. H. Chem.
Commun. 2002, 146. (q) Namboodiri, V. V.; Varma, R. S.
Chem. Commun. 2002, 342. (r) Farmer, V.; Welton, T. Green
Chem. 2002, 4, 97. (s) Kmentov a´ , I.; Gotov, B.; Solc a´ niov a´ ,
E.; Toma, S. Green Chem. 2002, 4, 103. (t) Seddon, K.; Stark,
A. Green Chem. 2002, 4, 119. (u) Ross, J.; Xiao, J. Green
Chem. 2002, 4, 129. (v) Ohara, H.; Kiyokane, H.; Itoh, T.
Tetrahedron Lett. 2002, 43, 3041. (w) Ansari, I. A.; Gree, R.
Org. Lett. 2002, 4, 1507. (x) Dupont, J.; Fonseca, G. S.;
Umpierre, A. P.; Fichtner, P. F. P.; Teixeira, S. R. J. Am Chem.
Soc. 2002, 124, 4228.
volume of the ionic liquid [bmim][PF ] was 0.8 mL;
6
1
13
31
spectral data (IR, H, C and P NMR) identical to the
initial [bmim][PF ] sample.
6
Acknowledgements
We thank Funda c¸ a˜ o para a Ci eˆ ncia e Tecnologia (project
PRAXIS/C/QUI/10069/98) for financial support.
References
6
7
. (a) Brown, R. A.; Pollet, P.; McKoon, E.; Eckert, C. A.; Liotta,
C. L.; Jesssop, P. G. J. Am. Chem. Soc. 2001, 123, 1254.
1
. (a) Holbrey, J. D.; Seddon, K. R. J. Chem. Soc. Dalton Trans
999, 13, 2133. (b) Huddleston, J. G.; Visser, A. E.; Reichert,
1
(
b) Sellin, M. F.; Webb, P. B.; Cole-Hamilton, D. J. Chem.
W. M.; Willauer, H. D.; Broker, G. A.; Rogers, R. D. Green
Chem. 2001, 3, 156. (c) Larsen, A. S.; Holdbrey, J. D.; Tham,
F. S.; Reed, C. A. J. Am. Chem. Soc. 2000, 122, 7264.
Commun. 2001, 781. (c) Fadeev, A. G.; Meagher, M. M.
Chem. Commun. 2001, 295.
. (a) Huddleston, J. G.; Willauer, H. D.; Swatloski, R. P.; Visser,
A. E.; Rogers, R. D. Chem. Commun. 1998, 1765. (b) Cull,
S. G.; Holbrey, J. D.; Vargas-Mora, V.; Seddon, K. R.; Lye,
G. J. Biotechnol. Bioeng. 2000, 69, 227. (c) Visser, A. E.;
Swatloski, R. P.; Reichert, W. M.; Griffin, S. T.; Rogers, R. D.
Ind. Eng. Chem. Res. 2000, 39, 3596. (d) Visser, A. E.;
Swatloski, R. P.; Reichert, W. M.; Mayton, R.; Sheff, S.;
Wierzbicki, A.; Davies, J. H.; Rogers, R. D. Chem. Commun.
2001, 135. (e) Blanchard, L. A.; Brennecke, J. F. Ind. Eng.
(
d) Wilkes, J. S.; Levisky, J. A.; Wilson, R. A.; Hussey, C. L.
Inorg. Chem. 1982, 21, 1263. (e) Bonh oˆ te, P.; Dias, A.-P.;
Papageorgiou, N.; Kalyanasundaram, K.; Gr a¨ tzel, M. Inorg.
Chem. 1996, 35, 1168. (f) Suarez, P. A. Z.; Dullius, J. E. L.;
Einloft, S.; de Souza, R. F.; Dupont, J. Polyhedron 1996, 15,
1
217. (g) Cole, A. C.; Jensen, J. L.; Ntai, I.; Tran, K. L. T.;
Weaver, K. J.; Forbes, D. C.; Davis, Jr., J. H. J. Am. Chem.
Soc. 2002, 124, 5962. (h) Branco, L. C.; Rosa, J. N.; Ramos,
J. J. M.; Afonso, C. A. M. Chem. Eur. J. 2002, 8, 3671.