19115-79-8Relevant academic research and scientific papers
C(10)-C(19) bond cleavage reaction of 19-oxygenated androst-4-ene-3,6-dione steroids under various conditions
Nagaoka, Masao,Numazawa, Mitsuteru
, p. 983 - 985 (2007/10/03)
C(10)-C(19) bond cleavage reaction of 19-hydroxy- and 19-oxoandrost-4-ene- 3,6,17-triones (5, 6) was explored under various conditions. Treatment of steroids 5 and 6 with KOH in MeOH gave the A-ring aromatized product 6-oxoestrone (11) in a fair yield, respectively, in contrast, the treatment with a weak base yielded 4-methyl steroid 17 (20%) in the case of 19-alcohol 5 or 19-nor- Δ5(10)-steroid 9 (12-67%) along with compound 11 (6-27%) in the case of 19-aldehyde 6. Reaction of compound 6 with HCl in MeOH produced 3-methyl ethers of 6-oxoestrone and Δ6-estrone, compounds 12 and 14 (ca. 20% each). Thus, 6-oxosteroids 5 and 6 showed unique C(10)-C(19) bond cleavage reactions with a base or acid.
PROCESS FOR THE PREPARATION OF STEROID DERIVATIVES
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Example 1, (2008/06/13)
A method of producing 3-alkoxy-1,3,5(10)-triene-6-one-steroid derivatives having, in the steroid skeleton thereof, a partial structure of A- and B-rings represented by formula (2) : (wherein R represents an alkyl group, a cycloalkyl group, an alkenyl group, or an aralkyl group), including reacting a 19-norsteroid derivative having, in the steroid skeleton thereof, a partial structure of A- and B-rings represented by formula (1) : with an alcohol represented by ROH (wherein R has the same meaning as defined above) and iodine in the absence of a rare earth compound catalyst. According to the method of the present invention, 3-alkoxy-1,3,5(10)-triene-6-one-steroids can be selectively produced from 19-norsteroides through a single reaction step without employment of a special catalyst.
Copper bromide mediated A-ring dehydrogenation of 19-norsteroids
Brito,Campos,Salgado-Zamora,Fabbro
, p. 623 - 629 (2007/10/03)
A dehydrogenation reaction applied to 19-norsteroids 1a or 1b, with copper(II) bromide in different alcohols yielded estrone alkyl ethers or 13β-ethyl-3-alkoxy gonanes along with products in which the steroid 6-position has been oxidized as aell. Use of small amounts of trialkyl orthoformates in the reaction considerably diminished the overoxidized products.
Preparative chemical methods for aromatization of 19-nor-Δ4-3-oxosteroids
Rao, Pemmaraju N.,Cessac, James W.,Kim, Hyun K.
, p. 621 - 627 (2007/10/02)
Two preparative chemical methods for aromatization of 19-nor-Δ4-3-oxosteroids are described.The first method consists of an oxidative aromatization of 19-nor-Δ4-3-oxosteroids with iodine-ceric ammonium nitrate in methanol to give a mixture of 3-methoxy ring-A aromatized derivatives consisting of the desired product, the Δ9,11 derivative, the 6-oxo derivative as well as some ring-A iodinated material.Conversion of this material to a mixture of the 3-methoxy ring-A aromatized derivative and its 6-oxo derivative was achieved by catalytic hydrogenation.Finally, reduction of the 6-oxo function with triethylsilane in trifluoroacetic acid gave the 3-methoxy-17-trifluoroacetate ring-A aromatized derivative as a single product.In the second method, reaction of 19-nor-Δ4-3-oxosteroids with copper(II) bromide in acetonitrile at room temperature resulted in aromatic steroids in a single step in excellent yields.The second method was used in the first practical chemical synthesis of a 6-dehydroestrogen from a 19-nor-Δ4,6-3-oxosteroid. - Keywords: copper(II) bromide; ceric ammonium nitrate; iodine; aromatization; 19-nor-Δ4-3-oxosteroids
