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Jul-Aug 2005
Synthesis and H NMR Structural Analysis of 11-aryl/heteroarylnaphtha[2,1-b]furans
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-(Naphthalen-2-yloxy)-1-(4'-methoxyphenyl)-ethanone (5).
Anal. Calcd. for C18H NO : C, 74.74; H, 3.80; N, 4.84.
11 3
Found: C, 74.42; H, 3.68; N, 4.63.
Following the general procedure, the reaction of 2'-bromo-4-
methoxyacetophenone with 2-naphthol was carried out for 24 hr.
The crude product was purified by SiO column chromatography
11-(4'-Pyridyl)naphtho[2,1-b]furan (10).
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The cyclization of 7 using the general procedure gave up on
work-up a crude solid which was purified by SiO column chro-
matography (elution with pet. ether-CHCl , 1:2) to provide 10 as
(
elution with pet. ether:CHCl 1:3) to provide 5 as a colourless
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solid, mp 85-87 °C in 60% yield. H NMR (CDCl ): δ 4.2 (3H, s,
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νmax/cm ): 3030, 1690, 1605, 1456, 1310, 1260. 1110, 945.
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3
OCH ), 5.5 (2H, s, -CH ), 7.0-8.3 (11H, m, ArH); IR (KBr,
3 2
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a pale yellow solid, mp 105-107 °C in 40% yield. H NMR, see
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Table 1.IR (KBr, νmax/cm ): 3010, 1600, 1488, 1432, 1342,
229, 10010, 1040, 940.
Anal. Calcd. for C H NO: C, 83.26; H, 4.48; N, 5.71. Found:
Anal. Calcd. for C
H O : C, 78.08; H, 5.47. Found: C,
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9
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7
2
8.21; H, 5.47.
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7 11
-(Naphthalen-2-yloxy)-1-(4'-nitrophenyl)-ethanone (6).
C, 83.49; H, 4.31; N, 5.89.
Following the general procedure, the reaction of 2'-bromo-4-
11-(N-Methyl-4'-pyridinium)naphtho[2,1-b]furan Iodide (11).
Compound 10 (0.122 g, 0.5 mmol) was dissoved in dry THF (2
nitroacetophenone with 2-naphthol was carried out for 12 hr. The
crude product was purified by SiO column chromatography (elu-
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ml) and a few drops of CH I were added. The reaction flask was
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tion with pet. ether:CHCl 1:3) to provide compound 6 as a pale
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tightly stoppered and left at room temperature for a week to
deposit crystals of 11. The solvent was decanted out, crystals
washed with little THF and dried under vacuum dessicator to
give quantitative yield of 11 as a pale yellow crystalline solid, mp
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yellow solid, mp 148-149 °C in 30% yield. H NMR (CDCl ): δ
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5
3
.3 (2H, s, -CH ), 7.0-8.35 (11H, m, ArH); IR (KBr, νmax/cm ):
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030, 1710, 1600,1520, 1425, 1340, 1210, 1085, 949.
Anal. Calcd. for C18H13NO : C, 70.35; H, 4.23; N, 4.56.
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2
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42-243 °C. H NMR, see Table 1.IR (KBr, νmax/cm ): 3010,
Found: C, 70.14; H, 4.49; N, 4.32.
630, 1560, 1430, 1344, 1270, 1120, 1040, 915, 875.
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-(Naphthalen-2-yloxy)-1-(4'-pyridyl)-ethanone (7).
Anal. Calcd. for C H NOI: C, 55.81; H, 3.62; N, 3.62; I,
18 14
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3.07. Found: C, 55.63; H, 3.76; N, 3.55; I, 32.77.
Following the general procedure, the reaction of 2'-bromo-4-
acetylpyridine hydrobromide with 2-naphthol was carried out for
6 hr. The crude product was purified by SiO column chro-
Acknowledgements.
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Thanks are due to the C.S.I.R., New Delhi for the generous
financial support and Professor Marc Lemaire, University of
Lyon, France for scanning the 2D NMR spectra.
matography (elution with pet. ether:CHCl 1:1) to provide com-
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pound 7 as a colourless solid, mp 136-138 °C in 29% yield. H
NMR (CDCl ): δ 3.35 (2H, s, -CH ), 7.0-8.65 (11H, m, ArH); IR
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2
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1
(
1
KBr, νmax/cm ): 3030, 1635, 1635,1500, 1455, 1338, 1230,
066, 930.
Anal. Calcd. for C17H13NO : C, 77.56; H, 4.94; N, 5.32.
REFERENCES
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[
1] G. P. Moss, Pure Appl. Chem., 68, 2193 (1996); K. Mislow
Found: C, 77.44; H, 4.72; N, 5.12.
and J. Siegel, J. Am. Chem. Soc., 106, 3319 (1984); P. Lloyd-William and
E. Giralt, Chem. Soc. Rev., 39, 145 (2001); Noyori in Stereocontrolled
Organic Synthesis, Ed.: B. M. Trost, 1994, 1-15: Blackwell, Oxford, UK.
M. Oki Top. Steroechem. 14, 1-81(1983).
General Procedure for the Preparation of Naphthofurans 8-10.
Appropriate naphthoxy-ketone (1 mmol) was dissolved in neat
methanesulphonic acid (2.5 ml) and the reaction was allowed to
proceed at room temperature overnight. The reaction mixture was
[
2] M. Nieger, H. Hupfer and M. Bolte, Acta Cryst., C54, 656,
(
1998); M. Maus and W. Rettig, J. Chem. Phys. 218, 151, (1997); L.
diluted with cold water, neutralized with saturated Na CO solu-
2
3
Huang, Y. K. Si, G. Snatzke, D. K. Zheng, J. Zhou, Collect. Czech. Chem.
Commun. 53, 2664 (1988).
tion and extracted with CH Cl . The organic extract was washed
2
2
repeatedly with water and dried over anhydrous Na SO . Removal
[3] P. Acharya, O. Plashkevych, C. Morita, S. Yamada and J.
Chattopadhyaya, J. Org. Chem., 68, 1529, (2003) and references cited
therein; T. Itahara, J. Chem. Soc., Perkin Trans. 2, 1455, (1998); M. J.
Rashkin and M. L. Waters, J. Am. Chem. Soc., 124, 1860, (2002).
2
4
of solvent gave a crude solid, which was purified by SiO column
2
chromatography to provide the desired naphthofuran.
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1-(4'-Methoxyphenyl)naphtho[2,1-b]furan (8).
The cyclization of 5 using the general procedure gave up on
work-up a crude solid which was purified by SiO column chro-
[
4] T. H. Webb and C. S. Wilcox, Chem. Soc. Rev., 22, 383,
(
1993); A. J. Goodman, E. C. Breinlinger, C. M. McIntosh and L. N.
Rotello, Org. Lett., 3, 1531, (2001); P Leighton, J. A. Cowan, R. J.
Abraham and J. K. M. Sanders, J. Org. Chem., 53, 733, (1988).
2
matography (elution with pet. ether-CHCl , 1:4) to provide 8 as a
3
[
5] G. W. Gray and J. E. Lydon, Nature , 252, 221, (1974); J.
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colourless solid, mp 136-138 °C in 45% yield. H NMR, see
Table 1.IR (KBr, νmax/cm ): 3030, 2930, 1600, 1505, 1436,
Nakaughi and Y. Kageyama, Bull. Chem. Soc. Jpn. 61, 2573, (1988); P.
Zugenmaier and A. Heiski, Liquid Crystals, 15, 835, (1993); L. E.
Ochando, A. M. Costero, E. Monrabal and M. Pitarch, Cryst. Res.
Technol. 36, 223, (2001).
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328, 1260, 1050, 945.
Anal. Calcd. for C19H14O : C, 83.21; H, 5.11. Found: C,
2
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3.08; H, 5.38.
[6] P. R. Ranjbar, S. T. Ganjali, S. L. Wang, F. L. Liao and A.
Heydari, J. Chem. Soc. Perkin Trans 2, 1255, (2001).
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1-(4'-Nitrophenyl)naphtho[2,1-b]furan (9).
The cyclization of 6 using the general procedure gave up on
work-up a crude solid which was purified by SiO column chro-
[7] F. Thiel, Angew. Chem. Int. Ed., 38, 2345, (1999).
[
8] G. Bringmann, W. Saeb and M. Rubenacker, Tetrahedron, 55,
23, (1999).
9] G. Bringmann, R. Walter and R. Weirich, Angew. Chem. Int.
Ed., 29, 977, (1990).
10] G. Bringmann and F. Pokorny, The Alkaloids. Chemistry and
4
2
[
matography (elution with pet. ether-CHCl , 1:4) to provide 9 as a
pale yellow solid, mp 139-140 °C in 55% yield. H NMR, see
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[
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Table 1. IR (KBr, νmax/cm ): 3010, 2930, 1600, 1514, 1418,
Pharmacology, 46 (Ed: G. A. Cordell) Academic Press, San Diego, CA
(1995).
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340, 1255 1040, 875.