Regioselective introduction of electrophiles in the 4-position of 1- hydroxypyrazole via bromine-lithium exchange

Journal of Organic Chemistry

Volumn 64, Issue 15, 1999, Pages 5366-5370

  Balle, Thomas ^a,b   Vedsø, Per ^a   Begtrup, Mikael ^a  

^a UNIVERSITY OF COPENHAGEN   (Denmark)

^b TECHNICAL UNIVERSITY OF DENMARK   (Denmark)

Author keywords

[No Author keywords available]

Indexed keywords

BROMINE; LITHIUM; PYRAZOLE DERIVATIVE; TRIFLUOROACETIC ACID;

ARTICLE; CHEMICAL INTERACTION; CHEMICAL REACTION; SYNTHESIS;

EID: 0033597746     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo981970w     Document Type: Article

References (31)

1. For a recent review on lithiated pyrazoles, see: Grimmett, M. R.; Iddon, B. Heterocycles 1994, 37, 2087.
2. Vedsø, P.; Begtrup, M. J. Org. Chem. 1995, 60, 4995.
3. Fugina, N.; Holzer, W.; Wasicky, M. Heterocycles 1992, 34, 303.
4. Katritzky, A. R.; Lue, P.; Akutagawa, K. Tetrahedron 1989, 45, 4253.
5. Hüttel, R.; Schäfer, O.; Jochum, P. Liebigs Ann. Chem. 1965, 593, 200.
6. Lipp, M.; Dallacker, F.; Munnes, S. Liebigs Ann. Chem. 1968, 618, 110.
7. Hüttel, R.; Büchele, F.; Jochum, P. Chem. Ber. 1955, 88, 1577.
8. Büttel, R.; Schön, M. E. Liebigs Ann. Chem. 1959, 625, 55.
9. Hahn, M.; Heinisch, G.; Holzer, W.; Schwarz, H. J. Heterocycl. Chem. 1991, 28, 1189.
10. Iwata, S.; Qian, C.-P.; Tanaka, K. Chem. Lett. 1992, 357.
11. Sakamoto, T.; Shiga, F.; Uchiyama, D.; Kondo, Y.; Yamanaka, H. Heterocycles 1992, 33, 813.
12. Elguero, J.; Jaramillo, C.; Pardo, C. Synthesis 1987, 563.
13. Jeon, D. J.; Yu, D. W.; Yun, K. Y.; Ryu, E. K. Synth. Commun. 1998, 28, 2159.
14. 1H NMR.
15. Tertov, B. A.; Morkovnik, A. S. Chem. Heterocycl. Compd. (Engl. Transl.) 1975, 11, 343.
16. Uhlmann, P.; Felding, J.; Vedsø, P.; Begtrup, M. J. Org. Chem. 1961, 62, 9177.
17. Eaborn, C.; Seconi, G. J. Chem. Soc., Perkin Trans. 2 1976, 925.
18. Krizan, T. D.; Martin, J. C. J. Am. Chem. Soc. 1983, 105, 6155.
19. Caron, S.; Hawkins, J. M. J. Org. Chem. 1998, 63, 2054.
20. 22 have reported the preparation of 3-lithio-1-methylpyrazole via bromine-lithium exchange.
21. Begtrup, M.; Vedsø, P. J. Chem. Soc., Perkin Trans. 1 1993, 625.
22. Pavlik, J. W.; Kurzweil, E. M. J. Heterocycl. Chem. 1992, 29, 1357.
23. Narasimhan, N. S.; Sunder, N. M.; Ammanamanchi, R.; Bonde, B. D. J. Am. Chem. Soc. 1990, 112, 4431.
24. 25
25. Begtrup, M.; Boyer, G.; Cabildo, P.; Cativiela, C.; Claramunt, R. M.; Elguero, J.; Garcia, J. I.; Toiron, C.; Vedsø, P. Magn. Reson. Chem. 1993, 31, 107.
26. Effenberger, F.; Krebs, A. J. Org. Chem. 1984, 49, 4687.
27. Begtrup, M.; Vedsiø, P. J. Chem. Soc., Perkin Trans. 1 1995, 243.
28. Suffert, J. J. Org. Chem. 1989, 54, 509.
29. Using only 1 equiv of n-BuLi/TMEDA resulted in 48% starting material 1c together with 44% of 1-phenyl-1-pentanol and 41% of 3.
30. Birkofer, L.; Franz, M. Chem. Ber. 1972, 105, 1759.
31. 6 partially desilylated upon attempted flash chromathography.