Tetrahedron, 1997, 53, 17543; T. Naito, Heterocycles, 1999, 50, 505;
J 8.1, 10-H) and 8.41 (1 H, dd, J 8.0, 7-H); δC 55.78 (MeO),
106.24 (9-C), 117.02 (8-C), 118.63 (10-C), 121.53 (10a-C),
121.64 (7-C), 128.91 (4-C), 130.59 (3-C), 134.50 (6a-C) and
134.69 (1-C); m/z 226 (Mϩ, 100%), 211 (63), 183 (48), 155 (22),
127 (50) and 101 (20).
L. Yet, Tetrahedron, 1999, 55, 9349.
2 W. R. Bowman, H. Heaney and B. M. Jordan, Tetrahedron, 1991, 47,
10119.
3 A. M. Rosa, A. M. Lobo, P. S. Branco, S. Prabhakar and A. M. D.
L. Pereira, Tetrahedron, 1997, 53, 269.
4 A. M. Rosa, A. M. Lobo, P. S. Branco and S. Prabhakar,
Tetrahedron, 1997, 53, 285.
3-Methoxy-6H-benzo[c]chromen-6-one 1
5 A. M. Rosa, A. M. Lobo, P. S. Branco, S. Prabhakar and
M. Sá-da-Costa, Tetrahedron, 1997, 53, 299; C. Tsuge, T. Halta
and H. Tsuchiyama, Chem. Lett., 1998, 155; M. L. E. N. da Mata,
W. B. Motherwell and F. Ujjainwalla, Tetrahedron Lett., 1997, 38,
137, 141; W. B. Motherwell, A. M. K. Pennell and F. Ujjainwalla,
J. Chem. Soc., Chem. Commun., 1992, 1067; W. B. Motherwell and
A. M. K. Pennell, J. Chem. Soc., Chem. Commun., 1991, 877.
6 D. Crich and J.-T. Hwang, J. Org. Chem., 1998, 63, 2765.
7 T. Nakanishi, M. Suzuki, A. Mashiba, K. Ishikawa and T.
Yokotsuka, J. Org. Chem., 1998, 63, 4235.
The general procedure for PCC oxidations with 3-methoxy-6H-
benzo[c]chromene 25 (0.13 g, 0.59 mmol) yielded 3-methoxy-
6H-benzo[c]chromen-6-one 1 as a pungent smelling, brilliant
white powder (0.13 g, 100%), mp 123–129 ЊC (lit.34 mp 143 ЊC)
(Found: Mϩ, 226.0634. C14H10O3 requires 226.0630); νmax
-
(Nujol)/cmϪ1 2924, 2854, 1735, 835 and 761; δH 3.88 (3 H, s,
MeO), 6.88–6.95 (2 H, m, 2- and 4-H), 7.50 (1 H, dd, J 7.6, 7.6,
9-H), 7.78 (1 H, dd, J 7.6, 7.6, 8-H), 7.96 (1 H, d, J 8.7, 1-H),
8.33 (1 H, d, J 7.6, 10-H) and 8.33 (1 H, d, J 7.6, 7-H); δC 55.62
(MeO), 101.53 (9-C), 112.37 (8-C), 123.70 (7-C), 127.65 (4a-C),
127.72 (1-C), 130.47 (2-C), 134.80 (4-C), 135.01 (6a-C), 152.52
8 F. Aldabbagh, W. R. Bowman, E. Mann and A. M. Z. Slawin,
Tetrahedron, 1999, 55, 8111.
9 F. Aldabbagh and W. R. Bowman, Tetrahedron, 1999, 55, 4109.
10 T. C. T. Ho and K. Jones, Tetrahedron, 1997, 53, 8287.
11 Y. Antonio, M. A. E. De La Cruz, E. Galeazzi, A. Guzman,
B. L. Bray, R. Greenhouse, L. J. Kurz, D. A. Lustig, M. L. Maddox
and J. M. Muchowski, Can. J. Chem., 1994, 72, 15.
12 F. E. Ziegler and M. Belema, J. Org. Chem., 1997, 62, 1083 and
references therein; C. J. Moody and C. L. Norton, J. Chem. Soc.,
Perkin Trans. 1, 1997, 2639.
(C᎐O) and 161.51 (3-C); m/z 226 (Mϩ, 63%), 211 (9), 184 (8),
᎐
183 (68), 155 (38), 139 (30), 127 (100), 126 (45), 133 (19) and
101 (31).
1-Benzyloxy-6H-benzo[c]chromen-6-one 36
13 A. Padwa, M. Dimitroff, A. G. Waterson and T. Wu, J. Org. Chem.,
1998, 63, 3986.
14 J . A. Murphy and M. S. Sherburn, Tetrahedron, 1991, 47, 4077; and
references therein.
15 D. J. Hagan, E. Giménez-Arnau, C. H. Schwalbe and M. F. G.
Stevens, J. Chem. Soc., Perkin Trans. 1, 1997, 2739.
16 A. Nadin and T. Harrison, Tetrahedron Lett., 1999, 40, 4073.
17 D. C. Harrowven and M. I. T. Nunn, Tetrahedron Lett., 1998, 39,
5875.
18 H. Josien, S.-B. Ko, D. Bom and D. P. Curran, Chem. Eur. J., 1998,
4, 70; and references therein.
19 D. P. Curran and H. Liu, J. Chem. Soc., Perkin Trans. 1., 1994, 1377.
20 A. L. J. Beckwith and J. M. D. Storey, J. Chem. Soc., Chem.
Commun., 1995, 977.
21 Leading references: P. Phillips, Chem. Br., 1997, 32; S. Ghosal, Pure
Appl. Chem., 1990, 62, 1285; S. Ghosal, J. Lal, S. K. Singh,
Y. Kumar and F. Doti, J. Chem. Res. (S), 1989, 350; S. Ghosal,
S. K. Singh and R. S. Srivatava, J. Chem. Res. (S), 1988, 196.
22 A. J. Kirby, Stereoelectronic Effects, Oxford University Press,
Oxford, 1996, pp. 22–24.
23 Some leading references: D. L. J. Clive and P. L. Beaulieu, J. Chem.
Soc., Chem. Commun., 1983, 307; D. P. Curran and J. Tamine, J. Org.
Chem., 1991, 56, 2746; V. H. Rawal, S. P. Singh, C. Dufour and
C. Michoud, J. Org. Chem., 1991, 56, 5245; R. Nougier, S. Gastaldi,
D. Stein, M. Bertrand and P. Renaud, Tetrahedron Lett., 1999, 40,
3371; A. L. J. Beckwith and P. E. Pigou, J. Chem. Soc., Chem.
Commun., 1986, 85.
The general procedure for PCC oxidations with a clean mix-
ture (0.29 g) of 1- and 3-benzyloxy-6H-benzo[c]chromene 28
afforded 1-benzyloxy-6H-benzo[c]chromen-6-one 36 as a col-
ourless solid (17.80 mg, 63%) (Found Mϩ, 302.0943. C20H14O3
requires 302.0943); νmax(neat)/cmϪ1 3065, 3032, 2921, 1604, 790
and 718; δH(400 MHz) 5.31 (2 H, s, CH2O), 6.94 (1 H, dd, J 8.3,
1.1, 2- or 4-H), 7.05 (1 H, dd, J 8.3, 1.1, 2- or 4-H), 7.36–7.46 (5
H, m, Ph-H), 7.38 (1 H, t, J 8.3, 3-H), 7.50–7.53 (1 H, m, 9-H),
7.69 (1 H, ddd, J 8.4, 7.3, 1.6, 8-H), 8.43 (1 H, ddd, J 8.4, 1.0,
0.5, 10-H) and 9.05 (1 H, ddd, J 8.4, 1.0, 0.5, 7-H); δC(100 MHz)
71.83 (CH2O), 108.64 (2- or 4-C), 111.10 (2- or 4-C), 121.50 (6a-
C), 127.95 (7-C), 128.17 (9-C), 128.44 (phenyl-CH), 128.73
(phenyl-CH), 129.15 (3-C), 130.26 (phenyl-CH), 130.57 (10-C),
130.97 (PhCH2O), 134.93 (10a-C), 135.17 (8-C), 136.40 (10b-C),
153.06 (4a-C), 157.85 (1-C) and 161.81 (C᎐O); m/z 302 (Mϩ,
᎐
80%), 212 (7), 183 (9), 167 (10), 139 (8), 127 (29), 113 (4), 101
(10), 91 (100), 84 (17), 71 (7) and 65 (36). 3-Benzyloxy-6H-
benzo[c]chromen-6-one was also afforded (7.63 mg, 27%);
δH(400 MHz) 5.14 (2 H, s, CH2O), 6.99 (1 H, dd, J 8.8, 2.6,
2-H), 7.78 (1 H, ddd, J 15.36, 8.7, 1.4, 9-H), 7.96 (1 H, d, J 8.8,
1-C), 7.90 (1 H, d, J 8.4, 10-H) and 8.35 (1 H, ddd, J 8.0, 1.4,
0.5, 7-H). The 3-benzyloxy analogue was not fully chracterised.
2-Chloro-6H-benzo[c]chromen-6-one and 9-chloro-2-methyl-
6H-benzo[c]chromen-6-one were also synthesised by PCC
oxidation and their characterisation data are provided as sup-
plementary data.
24 A. L. J. Beckwith and J. M. D. Storey, Australian National
University, Canberra, unpublished results.
25 C. Wang, G. A. Russell and W. S. Trahanovsky, J. Org. Chem., 1998,
63, 9956; and references therein.
26 A. E. Lakach, A. N. Santiago and R. A. Rossi, J. Phys. Org. Chem.,
1994, 7, 610; and references therein.
Acknowledgements
We thank the EPSRC Mass Spectrometry Service at the Uni-
versity of Wales, Swansea, for running mass spectra and also
Loughborough University for a studentship (E. M.).
27 D. P. Curran, H. Yu and H. Lie, Tetrahedron, 1994, 50, 7343.
28 P. S. Engel and W.-X. Wu, J. Am. Chem. Soc., 1989, 111, 1830.
29 I. P. Beletskaya, A. S. Sigeev, V. A. Kuzman, A. S. Tatikolov and
L. Hevesi, J. Chem. Soc., Perkin Trans. 2, 2000, 107.
30 W. K. Busfield, I. D. Jenkins and P. Van Le, Polym. Bull., 1997, 38,
149.
31 J. Clayden, J. J. A. Cooney and M. Julia, J. Chem. Soc., Perkin Trans.
1, 1995, 7.
32 C. G. Huang and P. Wan, J. Org. Chem., 1991, 56, 4846.
33 D. D. Hennings, S. Iwasa and V. H. Rawal, J. Org. Chem., 1997, 62,
2.
34 G. W. K. Cavill, F. M. Dean, J. F. E. Keenan, A. McGookin,
A. Robertson and G. B. Smith, J. Chem. Soc., 1958, 1544.
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