PAPER
Debenzylation of N-Benzylcarboxamides by N-Bromosuccinimide
3133
N-(3-Chloro-4-fluorophenyl)benzamide(7r)
MS (ESI): m/z = 249 [M]+.
1H NMR (400 MHz, CDCl3): d = 8.35 (s, 1 H), 7.85–7.95 (m, 4 H),
7.52–7.61 (m, 2 H), 5.80–6.20 (br, 1 H), 5.60 (br, 1 H).
HRMS (EI): m/z [M + H]+ calcd for C13H10ClFNO: 250.0435;
found: 250.0431.
1H NMR (400 MHz, CDCl3): d = 7.84–7.87 (m, 2 H), 7.75 (br, 1 H),
7.69–7.73 (m, 1 H), 7.43–7.61 (m, 4 H), 7.15 (m, 1 H).
13C NMR (100 MHz, DMSO-d6): d = 166.1, 155.0, 152.6, 136.9,
134.9, 132.3, 128.9, 128.1, 122.2, 121.0, 119.5, 117.2.
Nicotinamide (9l)28
MS (ESI): m/z = 123 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 9.03 (s, 1 H), 8.76 (d, J = 6.4 Hz,
1 H), 8.16–8.19 (m, 1 H), 7.41–7.44 (m, 1 H), 6.30 (br, 1 H), 6.00
(br, 1 H).
2-Amino-3-phenylpropanamide (9m)29
Benzamide (9a)28
MS (ESI): m/z = 147 [M+ – NH2], 120 [M+ – CONH2].
MS (ESI): m/z = 122 [M + H]+.
1H NMR (400 MHz, DMSO-d6): d = 8.09 (br, 2 H), 7.84 (br, 1 H),
7.58 (br, 1 H), 7.27–7.49 (m, 5 H), 3.95 (m, 1 H), 2.89–3.12 (m,
2 H).
1H NMR (400 MHz, CDCl3): d = 7.81 (d, J = 12.0 Hz, 2 H), 7.52–
7.56 (m, 1 H), 7.44–7.48 (m, 2 H), 6.20 (br, 1 H), 5.85 (br, 1 H).
4-Nitrobenzamide (9b)28
MS (ESI): m/z = 165 [M + H]+.
1H NMR (400 MHz, DMSO-d6): d = 8.31 (d, J = 13.6 Hz, 2 H), 8.10
(d, J = 13.6 Hz, 2 H), 8.29 (br, 1 H), 7.73 (br, 1 H).
Acknowledgment
The authors are grateful for financial support from the Chinese Aca-
demy of Sciences (KSCX2-YW-R-27) and seed funding from
GIBH. Prof. Dawei Ma from Shanghai Institute of Organic Chem-
istry (CAS) is gratefully acknowledged for helpful discussions and
advice.
4-Fluorobenzamide (9c)28
MS (ESI): m/z = 140 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 7.81–7.86 (m, 2 H), 7.10–7.16 (m,
2 H), 6.10 (br, 1 H), 5.65 (br, 1 H).
References
4-Methoxybenzamide (9d)28
(1) Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic
Synthesis, 3rd ed.; Wiley-Interscience: New York, 2003.
(2) For examples, see: (a) Willams, R. M.; Lee, B. H.; Miller,
M. M.; Anderson, O. P. J. Am. Chem. Soc. 1989, 111, 1073.
(b) Davies, S. G.; Dupont, J.; Easton, R. J. C.; Ichihara, O.;
McKenna, J. M.; Smith, A. D.; de Sousa, J. A. A. J.
Organomet. Chem. 2004, 689, 4184. (c) Kumar, Y.;Tewari,
N.; Nizar, H.; Rai, B. P.; Singh, S. K. Org. Process Res. Dev.
2003, 7, 933. (d) Palomo, C.; Aizpurua, J. M.; Mielgo, A.;
Linden, A. J. Org. Chem. 1996, 61, 9186.
MS (ESI): m/z = 152 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 7.71 (d, J = 11.6 Hz, 2 H), 6.86 (d,
J = 11.6 Hz, 2 H), 5.80 (br, 1 H), 5.55 (br, 1 H), 3.79 (s, 3 H).
4-Bromobenzamide (9e)28
MS (ESI): m/z = 200 [M+], 202 [M + 2]+.
1H NMR (400 MHz, CDCl3): d = 7.68 (d, J = 10.8 Hz, 2 H), 7.60 (d,
J = 10.8 Hz, 2 H), 6.15 (br, 1 H), 5.75 (br, 1 H).
(3) Williams, R. M.; Kwast, E. Tetrahedron Lett. 1989, 30, 451.
(4) Gigg, R.; Conant, R. J. Chem. Soc., Chem. Commun. 1983,
465.
(5) Semple, J. E.; Wang, P. C.; Lysenko, Z.; Joulie, M. M. J. Am.
Chem. Soc. 1980, 102, 7505.
4-Chlorobenzamide (9f)28
MS (ESI): m/z = 156 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 7.75 (d, J = 10.8 Hz, 2 H), 7.44 (d,
J = 10.8 Hz, 2 H), 6.05 (br, 1 H), 5.70 (br, 1 H).
(6) Deroose, F. D.; De Clercq, P. J. J. Org. Chem. 1995, 60, 321.
(7) Chern, C.-Y.; Huang, Y.-P.; Kah, W. M. Tetrahedron Lett.
2003, 44, 1039.
(8) Seki, M.; Mori, Y.; Hatsuda, M.; Yamada, S. J. Org. Chem.
2002, 67, 5527.
(9) Ishihara, K.; Hiraiwa, Y.; Yamamoto, H. Synlett 2000, 80.
(10) Ford, R. E.; Knowles, P.; Lunt, E.; Marshall, S. M.; Penrose,
A. J.; Ramsden, C. A.; Summers, A. J. H.; Walker, J. L.;
Wright, D. E. J. Med. Chem. 1986, 29, 538.
3-Chlorobenzamide (9g)29
MS (ESI): m/z = 156 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 7.81 (s, 1 H), 7.69 (d, J = 10.4 Hz,
1 H), 7.50–7.53 (m, 1 H), 7.42 (t, J = 11.6 Hz, 1 H), 6.15 (br, 1 H),
5.70 (br, 1 H).
2-Chlorobenzamide (9h)29
MS (ESI): m/z = 156 [M + H]+.
(11) For examples, see: (a) Pan, Y.; Holmes, C. P.; Tumelty, D.
J. Org. Chem. 2005, 70, 4897. (b) Semmelhack, M. F.;
Appapillai, Y.; Sato, T. J. Am. Chem. Soc. 1985, 107, 4577.
(c) Chern, C.-Y.; Huang, Y.-P.; Kan, W. M. Tetrahedron
Lett. 2003, 44, 1039.
(12) For examples, see: (a) Green, J.; Margolin, A. L.
Tetrahedron Lett. 1992, 33, 7759. (b) Haug, B. E.; Rich, D.
H. Org. Lett. 2004, 6, 4783. (c) Gordeev, M. F.; Patel, D.
V.; Barker, P. L.; Gordon, E. M. Tetrahedron Lett. 1994, 35,
7585.
(13) Paik, S.; Lee, J. Tetrahedron Lett. 2006, 47, 1813.
(14) Metallions, C.; Nerdinger, S.; Snieckus, V. Org. Lett. 1999,
1, 1183.
(15) Baker, S. R.; Parsons, A. F.; Wilson, M. Tetrahedron Lett.
1998, 39, 331.
1H NMR (400 MHz, CDCl3): d = 7.80 (d, J = 1.5 Hz, 1 H), 7.35–
7.43 (m, 3 H), 6.35 (br, 1 H), 5.90 (br, 1 H).
4-Methoxy-2-nitrobenzamide (9i)29
MS (ESI): m/z = 197 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 7.49–7.53 (m, 2 H), 7.15 (dd,
J = 2.8, 8.4 Hz, 1 H), 5.80 (br, 2 H).
1-Naphthamide (9j)30
MS (ESI): m/z = 172 [M + H]+.
1H NMR (400 MHz, CDCl3): d = 8.42 (d, J = 12.8 Hz, 1 H), 7.95 (d,
J = 8.4 Hz, 1 H), 7.88 (d, J = 8.8 Hz, 1 H), 7.71 (d, J = 8.8 Hz, 1 H),
7.40–7.61 (m, 3 H), 5.80–6.0 (br, 2 H).
2-Naphthamide (9k)31
(16) NMA initiated bromination of toluene. To a solution of
toluene (2.0 mmol) in CHCl3 (20 mL), NMA (0.2 mmol) and
MS (ESI): m/z = 172 [M + H]+.
Synthesis 2007, No. 20, 3129–3134 © Thieme Stuttgart · New York