Novel (E)-3-(2′-benzyloxy-6′-hydroxyphenyl)-5-styrylpyrazoles from (E)-2-styrylchromones

Heterocyclic Communications

Volumn 3, Issue 5, 1997, Pages 433-436

  Pinto, Diana C G A ^a   Silva, Artur M S ^a   Cavaleiro, José A S ^a  

^a UNIVERSITY OF AVEIRO   (Portugal)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0031315858     PISSN: 07930283     EISSN: None     Source Type: Journal    
DOI: 10.1515/HC.1997.3.5.433     Document Type: Article

References (17)

1. See for example: a) J. Elguero in Comprehensive Heterocyclic Chemistry; Ed. K. P. Potts, Pergamon Press, Oxford, Vol. 5, 1984, pp. 167. b) K. Takagi, M. Tanaka, Y. Murakami, H. Monta and T. Aotsura, Eur. J. Med. Chem.- Chim. Ther, 21, 65 (1986). c) M. A. P. Martins, R. Freitag, A. F. C.Flores and N. Zanatta,Synthesis, 1491 (1995).
2. See for example: a) J. Elguero in Comprehensive Heterocyclic Chemistry; Ed. K. P. Potts, Pergamon Press, Oxford, Vol. 5, 1984, pp. 167. b) K. Takagi, M. Tanaka, Y. Murakami, H. Monta and T. Aotsura, Eur. J. Med. Chem.- Chim. Ther, 21, 65 (1986). c) M. A. P. Martins, R. Freitag, A. F. C.Flores and N. Zanatta,Synthesis, 1491 (1995).
3. See for example: a) J. Elguero in Comprehensive Heterocyclic Chemistry; Ed. K. P. Potts, Pergamon Press, Oxford, Vol. 5, 1984, pp. 167. b) K. Takagi, M. Tanaka, Y. Murakami, H. Monta and T. Aotsura, Eur. J. Med. Chem.- Chim. Ther, 21, 65 (1986). c) M. A. P. Martins, R. Freitag, A. F. C.Flores and N. Zanatta,Synthesis, 1491 (1995).
4. J. Catalán, F. Fabero,R. M. Claramunt, M. D.Santa Maria, M. C.Foces-Foces,F. H. Cano, M. Martinez-Ripoll, J. Elguero and R. Sastre, J. Am. Chem. Soc., 114, 5039 (1992).
5. R. Ahmad, N. Ahmad, M. Zia-Ul-Haq and A. Wahid, J. Chem. Soc.Pak., 18, 38 (1996).
6. See for example: J. Sepúlveda-Arques, B. Abarca-González and M. Medio-Simón, Advances in Heterocyclic Chemistry, Academic Press, Oxford, 1995, pp. 339.
7. a) J. A. S. Cavaleiro, J. Elguero, M. L. Jimeno and A. M. S. Silva, Chem. Lett., 445 (1991).
8. b) A. M. S. Silva, D.C.G. A. Pinto and J. A. S. Cavaleiro, Tetrahedron Lett., 35, 5899 (1994).
9. c) D.C.G. A. Pinto, A. M. S. Silva and J. A. S. Cavaleiro, Tetrahedron Lett., 35, 9459 (1994).
10. d) D. C. G. A. Pinto, A. M. S. Silva and J. A. S. Cavaleiro, Heterocyclic Commun., 2, 145 (1996).
11. e) D.C.G.A. Pinto, A.M.S. Silva and J. A. S. Cavaleiro, J. Heterocycl. Chemistry, 33, 1887 (1996).
12. f) W. A. Price, A.M.S. Silva and J. A. S. Cavaleiro, Heterocycl., 36, 2601 (1993).
13. Experimental procedures: To a methanolic solution (50 ml) of the appropriate 2-styrylchromone 2 (1 mmol), was added hydrazine hydrate (0.2 ml, 4.1 mmole) or methylhydrazine (0.4 ml, 8.2 mmlole) and the reaction mixture was heated at reflux (70-75 °C) during 24 hours. After this period the solvent was evaporated to dryness; the residue was taken in chloroform (50 ml), washed with water and purified by silica gel column chromatography, using chloroform as eluent, giving (E)-3-(2́-benzyloxy-6́-hydroxyphenyl)-5-styrylpyrazoles 1 (1a, 40%; 1b, 65%; 1c, 67%; 1d, 66%; 1e, 53%; 1f, 66%; 1g, 40%; 1h, 40%; 1i, 40%; 1j, 38%; 1k 37%; 1l, 39%).
14. +., 100), 367 (40), 351 (12), 291 (37), 277 (17), 264 (14), 262 (14), 249 (21), 238 (10), 219 (14), 218 (13), 162 (7), 115 (10), 103 (6), 91 (93), 77 (7), 65 (13).
15. G. P. Ellis, in Chromenes, Chromanones and Chromones; Ed. G. P. Ellis, John Wiley & Sons, New York, Cap.X, 1977, pp.557.
16. A. Bax, J. Magn. Reson., 57, 314 (1984).
17. 13C resonances (δ, ppm from TMS) of C-3 and C-5 are the following: 1a 149.6 and 141.0; 1b 150.0 and 141.2; 1c 149.9 and 141.4; 1e 149.6 and 144.6; 1f 150.3 and 145.1.