NMR and MS) of all known products were identical with those of
authentic compounds. The following compounds were unknown.
5 (a) E. Guibe´-Jampel and M. Wakselman, J. Chem. Soc. D, 1971, 267;
(b) E. Guibe´-Jampel and M. Wakselman, Synthesis, 1977, 772.
6 M. Itoh, D. Hagiwara and T. Kamiya, Tetrahedron Lett., 1975, 4393.
7 S. Kim and J. I. Lee, Chem. Lett., 1984, 237.
8 G. Barcelo, J.-P. Senet and G. Sennyey, Synthesis, 1986, 627.
9 (a) D. V. Sweet, Registry of Toxic Effects of Chemical Substances
1985–86, U. S. Govt. Printing Office: Washington D.C., 1988, p. 3336;
(b) D. V. Sweet, Registry of Toxic Effects of Chemical Substances 1985–
86, U. S. Govt. Printing Office: Washington D. C., 1988, p. 4049.
10 (a) H.-J. Kno¨lker and T. Braxmeier, Tetrahedron Lett., 1996, 37, 5861;
(b) H.-J. Kno¨lker, T. Braxmeier and G. Schlechtingen, Angew. Chem.,
Int. Ed. Engl., 1995, 34, 2497.
(9-Ethyl-9H-carbazol-3-yl)carbamic acid tert-butyl ester
(Table 1, entry 14). Mp 161–162 ◦C; IR mmax (KBr) = 3165,
2960, 1726, 1608, 1526, 1332, 1255, 1158, 1045, 999, 820 cm−1;
dH (300 MHz; CDCl3; Me4Si) 1.52 (9H, s, O-t-Bu), 1.55 (3H, s,
Me), 4.33 (2H, d, J 7.10 Hz, CH2), 6.55 (1H, s, NHr), 7.19–7.45
(5H, m, Ph), 8.05–8.17 (2H, 2, Ph); dC (75 MHz, CDCl3; Me4Si)
13.80, 27.42, 37.58, 80.13, 108.41, 111.55, 118.56, 120.67, 122.76,
123.14, 125.72, 130.13, 136.13, 140.43, 153.129; MS (EI): m/z 310
(M+); Anal. Calcd. for C19H22N2O2: C, 73.52; H, 7.14; N, 9.03; O,
10.31%. Anal. Found: C, 73.51; H, 7.15; N, 8.96; O, 10.24%.
11 S. Darnbrough, M. Mervic, S. M. Condon and C. J. Burns, Synth.
Commun., 2001, 31, 3273.
12 ZrCl4: (a) A. K. Chakraborti and R. Gulhane, Synlett, 2004, 627;
Cu(BF4)2: (b) A. K. Chakraborti, R. Gulhane and Shivani, Synthesis,
2004, 111; BiO(ClO4)2 (c) A. K. Chakraborti, R. Gulhane and Shivani,
Synlett, 2003, 1805; Mg(ClO2)2: (d) A. K. Chakraborti, L. Sharma, R.
Gulhane and Shivani, Tetrahedron, 2003, 59, 7661; InCl3: (e) A. K.
Chakraborti and R. Gulhane, Tetrahedron Lett., 2003, 44, 6749;
HClO4–SiO2: (f) A. K. Chakraborti and R. Gulhane, Chem. Commun.,
2003, 1896; HBF4–SiO2: (g) A. K. Chakraborti and R. Gulhane,
Tetrahedron Lett., 2003, 44, 3521.
Dicyclohexylcarbamic acid tert-butyl ester (Table 1, entry 25).
Mp 58–59 ◦C; IR mmax (KBr) = 2970, 2934, 2853, 1678, 1435,
1367, 1295, 1240, 1157 cm−1; dH (300 MHz; CDCl3; Me4Si) 1.04–
1.77 (m, 31H); dC (75 MHz; CDCl3; Me4Si) 25.49, 26.22, 28.50,
31.21, 54.69, 78.84, 155.32; MS (APCI) m/z: 181 (M+ − 100);
Anal. Calcd. for C12H15N3O2: C, 72.55; H, 11.10; N, 4.98%. Anal.
Found: C, 72.48; H, 11.13; N, 5.08%.
13 (a) S. K. Garg, R. Kumar and A. K. Chakraborti, Synlett, 2005, 1370;
(b) S. K. Garg, R. Kumar and A. K. Chakraborti, Tetrahedron Lett.,
2005, 46, 1721.
14 A. K. Chakraborti, R. Thilagavathi and R. Kumar, Synthesis, 2004,
831.
References
15 A. K. Chakraborti, S. Bhagat and S. Rudrawar, Tetrahedron Lett., 2004,
45, 7641.
16 R. Kumar and A. K. Chakraborti, Tetrahedron Lett., 2005, 46, 8319.
17 R. C. Besra, S. Rudrawar and A. K. Chakraborti, Tetrahedron Lett.,
2005, 46, 6213.
18 S. V. Chankeshwara and A. K. Chakraborti, Tetrahedron Lett., 2006,
47, 1087.
19 (a) J. H. Clark, Green Chem., 1999, 1, 1; (b) P. Tundo, P. Anastas, D. S.
Black, J. Breen, T. Collins, S. Memoli, J. Miyamoto, M. Polyakoff and
W. Tumas, Pure Appl. Chem., 2000, 72, 1207.
20 (a) G. Losse and G. Su¨ptitz, Synthesis, 1990, 1035; (b) R.-H. Mattern,
Tetrahedron Lett., 1996, 37, 291; (c) M. M. Hansen and J. R. Riggs,
Tetrahedron Lett., 1998, 39, 2705.
21 H. Okumoto, S. Nishihara, S. Yamamoto, H. Hino, A. Nozawa and A.
Suzuki, Synlett, 2000, 991.
22 (a) R. L. Garrett, Designing Safer Chemicals in American Chemical
Society Symposium Series 640, ch. 1, R. L. Garrett and S. C. De
Vito, eds., American Chemical Society: Washington D. C., 1996;
(b) G. W. V. Cave, C. L. Raston and J. L. Scott, Chem. Commun., 2001,
2159.
23 J. Elkington, http://www.sustainability.co.uk/sustainability.htm.
24 HClO4–SiO2 was prepared following the reported procedure: A. K.
Chakraborti and R. Gulhane, Chem. Commun., 2003, 1896, cited under
ref 12.
1 (a) T. W. Greene and P. G. M. Wuts, Protective Groups in Organic
Synthesis, John Wiley and Sons, New York, 1999, 3rd edn.; (b) G.
Theodoridis, Tetrahedron, 2000, 56, 2339; (c) G. Sartori, R. Ballini, F.
Bigi, G. Bosica, R. Maggi and P. Righi, Chem. Rev., 2004, 104, 199.
2 (a) L. Grehn and U. Ragnarsson, Angew. Chem., Int. Ed. Engl., 1984,
23, 296; (b) L. Grehn and U. Ragnarsson, Angew. Chem., Int. Ed. Engl.,
1985, 24, 510; (c) M. J. Burka and J. G. Allen, J. Org. Chem., 1997, 62,
7054; (d) Y. Basel and A. Hassner, J. Org. Chem., 2000, 65, 6368.
3 NaHCO3 in MeOH under sonication: (a) J. Einhorn, C. Einhorn and
J.-L. Luche, Synlett, 1991, 37; Me4NOH·5H2O in MeCN: (b) E. M.
Khalil, N. L. Subasinghe and R. L. Johnson, Tetrahedron Lett., 1996,
37, 3441; NaHMDS in THF: (c) T. A. Kelly and D. W. McNeil,
Tetrahedron Lett., 1994, 35, 9003; Aqueous NaOH: (d) C. Lutz, V. Lutz
and P. Knochel, Tetrahedron, 1998, 54, 6385; K2CO3–Bu4NI in DMF:
(e) S. T. Handy, J. J. Sabatini, Y. Zhang and I. Vulfova, Tetrahedron
Lett., 2004, 45, 5057.
4 Yttria–zirconia: (a) R. K. Pandey, S. P. Dagade, R. K. Upadhyay, M. K.
Dongare and P. Kumar, ARKIVOC, 2002, (vii), 28; Zn(ClO4)2·6H2O:
(b) G. Bartoli, M. Bosco, M. Locatelli, E. Marcantoni, M. Massaccesi,
P. Melchiorre and L. Sambri, Synlett, 2004, 1794; ZrCl4: (c) G. V. S.
Sharma, J. J. Reddy, P. S. Lakshmi and P. R. Krishna, Tetrahedron Lett.,
2004, 45, 6963; LiOClO4: (d) A. Heydari and S. E. Hosseini, Adv. Synth.
Catal., 2005, 347, 1794.
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