Abstract
The bromination reaction on 3-keto-4,6-diene steroids, via an epoxide intermediate, with hydrobromic acid in acetic acid medium gives the corresponding 6-bromo derivative. On the other hand, bromination with molecular bromine and subsequent dehydrobromination in an aprotic solvent and basic media afforded the unexpected 4-bromo derivative. In this work we suggest an alternative mechanism for explaining the bromine transposition from C6 to C4.
Keywords
References
1.
Cabeza M.
,
Gutiérrez E.
,
Miranda R.
,
Heuze I.
,
Bratoeff E.
,
Flores G.
, and
Ramirez E.
Procedings Western Pharmacology Society , 1998 , 41 , 87 –88 .
2.
Bratoeff E.
,
Flores G.
,
Ramirez E.
,
Flores C.
,
Calderón O.
,
Hernández E.
,
Valencia N.
,
Martinez A.
,
Cabeza M.
, and
Miranda R.
Revista Mexicana de Ciencias Farmacéuticas , 1997 , 28 (6 ), 13 –19 .
3.
Calderón D.
,
Labra N.
,
Hernández J. L.
,
Rodriguez R.
,
Barragan G.
,
Castilla L.
,
Bratoeff E.
, and
Ramirez E.
Revista Mexicana de Ciencias Farmacéuticas , 1997 , 28 (1 ), 24 –29 .
4.
Zeelen F.J.
Medicinal Chemistry of Steroids , Elsevier Science Publishing Company. Inc. New York . 1990 , Vol. 15 , Chapter 9, p. 185 .
5.
Shapiro E.
,
Weber L.
, and
Harris H.
J. Med. Chem. , 1972 , 15 , 716 –720 .
6.
Kocór M.
, and
Gumulka M.
Tetrahedron Lett. , 1970 , 37 , 3227 –3228 .
7.
Drewes S.E.
,
Roos G. H. P.
Tetrahedron , 1988 , 44 , 4653 –4670 .
8.
Blunt J.W.
, and
Stothers J.
Organic Magnetic Resonance , 1977 , 9 (8 ), 439 –464 .
9.
Romer J.
,
Scheller D.
, and
Grossmann G.
Magnetic Resonance in Chemistry , 1987 , 25 , 135 –140 .