PAPER
Indium(III) Halides as Catalysts for N-tert-Butoxycarbonylation of Amines
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ate (Table 1, entry 1); yield: 0.485 g (~100%); white solid; mp 132–
133 °C.
IR (KBr): 2970, 2934, 2853, 1678, 1435, 1367, 1295, 1240, 1157
cm–1.
IR (KBr): 3314, 2985, 1689, 1598, 1531, 1245, 1150 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.04–1.77 (m, 31 H).
1H NMR (300 MHz, CDCl3): d = 1.51 (s, 9 H), 6.55 (br s, 1 H),
6.99–7.04 (m, 1 H), 7.24–7.36 (m, 4 H).
13C NMR (75 MHz, CDCl3): d = 25.49, 26.22, 28.50, 31.21, 54.69,
78.84, 155.32.
13C NMR (75 MHz, CDCl3): d = 28.3, 80.4, 118.5, 123, 128.9,
MS (APCI): m/z = 181 (M+ – 100).
138.3, 152.7.
Anal. Calcd for C17H31NO2: C, 72.55; H, 11.10; N, 4.98. Found: C,
72.45; H, 10.95; N, 4.95.
MS (ESI): m/z = 193 (M+).
Method B: The reactions with InCl3 were carried out in the same
way as those using InBr3.
References
The remaining reactions were carried out following these general
procedures (Method A and Method B). The physical data (mp, IR,
NMR and MS) of known compounds were found to be identical
with those of authentic samples. Unknown compounds were char-
acterised by spectral (IR, NMR and MS) and elemental analyses.
(1) (a) Greene, T. W.; Wuts, P. G. M. Protecting Groups in
Organic Synthesis, 3rd ed.; Wiley: New York, 1999.
(b) Theodoridis, G. Tetrahedron 2000, 56, 2339.
(c) Sartori, G.; Ballini, R.; Bigi, F.; Bosica, G.; Maggi, R.;
Righi, P. Chem. Rev. 2004, 104, 199.
(2) (a) Chakraborti, A. K.; Gulhane, R. Tetrahedron Lett. 2003,
44, 3521. (b) Chakraborti, A. K.; Gulhane, R. Chem.
Commun. 2003, 1896. (c) Chakraborti, A. K.; Gulhane, R.
Tetrahedron Lett. 2003, 44, 6749. (d) Chakraborti, A. K.;
Sharma, L.; Gulhane, R.; Shivani Tetrahedron 2003, 59,
7661. (e) Chakraborti, A. K.; Gulhane, R.; Shivani Synlett
2003, 1805. (f) Chakraborti, A. K.; Gulhane, R.; Shivani
Synthesis 2004, 111. (g) Chakraborti, A. K.; Gulhane, R.
Synlett 2004, 627.
The physical data of new compounds are provided below.
(4-Benzyloxyphenyl)carbamic Acid tert-Butyl Ester (Table 1,
Entry 9)
Off-white solid; mp 114–115 °C.
IR (KBr): 3428, 3294, 2986, 1696, 1590, 1527, 1450, 1326, 1228,
1152, 1055, 750 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.50 (s, 9 H), 5.03 (s, 2 H), 6.32
(s, 1 H), 6.90 (d, J = 8.82 Hz, 2 H), 7.24–7.43 (m, 7 H).
13C NMR (75 MHz, CDCl3): d = 28.93, 70.87, 80.80, 115.81,
121.07, 128.03, 128.48, 129.11, 132.25, 137.62, 153.73, 155.36.
(3) Dilbeck, G. A.; Field, L.; Gallo, A. A.; Gargiulo, R. J. J. Org.
Chem. 1978, 43, 4593.
(4) Agami, C.; Couty, F. Tetrahedron 2002, 58, 2701.
(5) Lutz, C.; Lutz, V.; Knochel, P. Tetrahedron 1998, 54, 6385.
(6) (a) Grehn, L.; Ragnarsson, U. Angew. Chem., Int. Ed. Engl.
1984, 23, 296. (b) Grehn, L.; Ragnarsson, U. Angew. Chem.,
Int. Ed. Engl. 1985, 24, 510. (c) Burk, M. J.; Allen, J. G. J.
Org. Chem. 1997, 62, 7054. (d) Basel, Y.; Hassner, A. J.
Org. Chem. 2000, 65, 6368.
MS (EI): m/z = 299 (M+).
Anal. Calcd for C18H21NO3: C, 72.22; H, 7.07; N, 4.68. Found: C,
71.99; H, 7.14; N, 4.71.
(9-Ethyl-9H-carbazol-3-yl)carbamic Acid tert-Butyl Ester
(Table 1, Entry 18)
Yellow solid; mp 161–162 °C.
(7) (a) NaHCO3 in MeOH under sonication: Einhorn, J.;
Einhorn, C.; Luche, J.-L. Synlett 1991, 37.
(b) Me4NOH·5H2O in MeCN: Khalil, E. M.; Subasinghe, N.
L.; Johnson, R. L. Tetrahedron Lett. 1996, 37, 3441.
(c) NaHMDS in THF: Kelly, T. A.; McNeil, D. W.
Tetrahedron Lett. 1994, 35, 9003. (d) Aqueous NaOH:
Lutz, C.; Lutz, V.; Knochel, P. Tetrahedron 1998, 54, 6385.
(e) K2CO3-Bu4NI in DMF: Handy, S. T.; Sabatini, J. J.;
Zhang, Y.; Vulfova, I. Tetrahedron Lett. 2004, 45, 5057.
(8) Guibé-Jampel, E.; Wakselman, M. J. Chem. Soc., Chem.
Commun. 1971, 267.
IR (KBr): 3165, 2960, 1726, 1608, 1526, 1332, 1255, 1158, 1045,
999, 820 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.31 (t, J = 6.82 Hz, 3 H), 1.54 (s,
9 H), 4.21 (q, J = 6.98 Hz, 2 H), 6.65 (br s, 1 H), 7.12–7.43 (m, 5
H), 7.99–8.13 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 14.35, 29.02, 38.10, 80.69, 109.02,
112.08, 119.10, 121.22, 123.31, 123.67, 126.27, 130.68, 137.23,
140.96, 154.14.
MS (EI): m/z = 310 (M+).
(9) Guibé-Jampel, E.; Wakselman, M. Synthesis 1977, 772.
(10) Itoh, M.; Hagiwara, D.; Kamiya, T. Tetrahedron Lett. 1975,
4393.
Anal. Calcd for C19H22N2O2: C, 73.52; H, 7.14; N, 9.03. Found: C,
73.51; H, 7.15; N, 8.96.
(11) Kim, S.; Lee, J. I. Chem. Lett. 1984, 237.
(12) Barcelo, G.; Senet, J.-P.; Sennyey, G. Synthesis 1986, 627.
(13) (a) Sweet, D. V. Registry of Toxic Effects of Chemical
Substances 1985-86; US Govt. Printing Office: Washington
DC, 1988, 3336. (b) Sweet, D. V. Registry of Toxic Effects
of Chemical Substances 1985-86; US Govt. Printing Office:
Washington DC, 1988, 4049.
(14) (a) Knölker, H.-J.; Braxmeier, T. Tetrahedron Lett. 1996,
37, 5861. (b) Knölker, H.-J.; Braxmeier, T.; Schlechtingen,
G. Angew. Chem., Int. Ed. Engl. 1995, 34, 2497.
(15) Darnbrough, S.; Mervic, M.; Condon, S. M.; Burns, C. J.
Synth. Commun. 2001, 31, 3273.
(2-Morpholin-4-yl-ethyl)carbamic Acid tert-Butyl Ester
(Table 1, Entry 22)
Yellow oil.
IR (neat): 2974, 2875, 1695, 1407, 1255, 1266, 1128 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.45 (s, 9 H), 2.17–2.45 (m, 6 H),
3.69–3.70 (m, 2 H), 4.11–4.13 (m, 4 H), 4.97 (s, 1 H).
13C NMR (75 MHz, CDCl3): d = 28.94, 37.31, 53.89, 58.15, 67.42,
79.80, 156.47.
MS (EI): m/z = 230 (M+).
(16) Pandey, R. K.; Dagade, S. P.; Upadhyay, R. K.; Dongare, M.
(17) Bartoli, G.; Bosco, M.; Locatelli, M.; Marcantoni, E.;
Massaccesi, M.; Melchiorre, P.; Sambri, L. Synlett 2004,
1794.
Anal. Calcd for C11H22N2O3: C, 57.37; H, 9.63; N, 12.16. Found: C,
57.14; H, 9.75; N, 12.04.
Dicyclohexylcarbamic Acid tert-Butyl Ester (Table 1, Entry 24)
Colourless solid, mp 58–59 °C.
Synthesis 2006, No. 16, 2784–2788 © Thieme Stuttgart · New York