10158-77-7Relevant academic research and scientific papers
INTRAMOLECULAR HYDROGEN ABSTRACTION. IODOSOBENZENE DIACETATE, AN EFFICIENT AND CONVENIENT REAGENT FOR ALKOXY RADICAL GENERATION
Concepcion, Jose I.,Francisco, Cosme G.,Hernandez, Rosendo,Salazar, Jose A.,Suarez, Ernesto
, p. 1953 - 1956 (1984)
Photolysis of several hydroxy compounds in presence of iodosobenzene diacetate and iodine leads to alkoxy radical derivatives which undergo intramolecular hydrogen abstraction to produce cyclic ethers in good yields.
SEVEN-MEMBERED CYCLIC TRANSITION STATE IN THE ALKOXY-RADICAL INDUCED INTRAMOLECULAR HYDROGEN ABSTRACTION OF 26-HYDROXY-FUROSTANS
Francisco, Cosme G.,Freire, Raimundo,Hernandez, Rosendo,Medina, Maria C.
, p. 4621 - 4624 (1983)
The photolysis of 26-hydroxy-furostan (5) and (8) in the presence of Pb(OAc)4/I2 affforded spirostan sapogenins (4) and (7) respectively in 80percent yield.This cyclization takes place by an uncommon 1,6-hydrogen shift involving a 7-membered transition state as demonstrated by using specifically deuterium labeled compounds.
Sarsasapogenin-structure-modified derivatives, pharmaceutical compositions thereof and applications of the compositions
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Paragraph 0094-0097, (2017/07/20)
The invention relates to sarsasapogenin-structure-modified derivatives. The derivatives are characterized in that the structure formulas of the derivatives are shown as (I) and (II); pharmaceutical compositions of the derivatives and applications thereof are also provided; and many of the newly synthesized compounds show activity superior to activity of lead compounds through activity testing aiming at AD related targets. The compositions have high practical value for treating senile dementia. Defects of sarsasapogenin-structure-modified derivatives in the prior art are made up. The derivatives and the compositions are of great significance.
Epimerization of C-22 in (25R)- and (25S)-sapogenins
Vias-Bravo, Omar,Merino-Montiel, Penlope,Romero-Lpez, Anabel,Montiel-Smith, Sara,Meza-Reyes, Socorro,Melndez, Francisco J.,Sandoval-Ramrez, Jess
, p. 60 - 67 (2015/01/30)
Most of the naturally occurring steroidal sapogenins (C-23 non-substituted frameworks), possess an R configuration at the spiro C-22 center. Their C-22 epimers have become important targets in biological research. This paper describes a procedure to obtain 22S-spirostans from 22R-sapogenins and pseudosapogenin skeletons, without affecting the chirality at either C-25 or C-20. An optimal way to synthesize the pair of C-22 stereoisomers of 23-acetyldiosgenin is also reported. The latter was obtained from a 22,26-epoxycholestane or from 23-acetylfurostene compounds.
Epimerization of C-22 in (25R)- and (25S)-sapogenins
Vi?as-Bravo, Omar,Merino-Montiel, Penélope,Romero-López, Anabel,Montiel-Smith, Sara,Meza-Reyes, Socorro,Meléndez, Francisco J.,Sandoval-Ramírez, Jesús
, p. 60 - 67 (2015/02/05)
Most of the naturally occurring steroidal sapogenins (C-23 non-substituted frameworks), possess an R configuration at the spiro C-22 center. Their C-22 epimers have become important targets in biological research. This paper describes a procedure to obtain 22S-spirostans from 22R-sapogenins and pseudosapogenin skeletons, without affecting the chirality at either C-25 or C-20. An optimal way to synthesize the pair of C-22 stereoisomers of 23-acetyldiosgenin is also reported. The latter was obtained from a 22,26-epoxycholestane or from 23-acetylfurostene compounds.
The crystal structure of 3-epismilagenin acetate and 23-oxo-3-epismilagenin acetate
MacIas-Alonso, Mariana,Esturau-Escofet, Nuria,Flores-Alamo, Marcos,Iglesias-Arteaga, Martin A.,Moreno-Esparza, Rafael
experimental part, p. 1476 - 1482 (2012/06/15)
The crystal structure together with unambiguous assignation of 1H and 13C NMR signals of 3-epismilagenin acetate 4 and 23-oxo-3-epismilagenin acetate 5 are described. Compound 4, crystallized as orthorhombic system a = 10.535(1) A, b = 13.775 (1) A, c = 18.347 (1) A, α = β = γ = 90°; with space group P2 1 2 1 2 1 ; while compound 5 crystallized as a monoclinic system a = 10.380(1) A, b = 7.327(1) A, c = 17.881(1) A, α = γ = 90°, β = 99.56(1)°, with a space group P2 1 . The presence a carbonyl group at C(23) in compound 5 produces a significant deviation from the chair conformation observed in compound 4. The effects of the side chain modifications on the puckering parameters derived from are discussed.
Cyanoglycosylation accompanied by ring-opening of spirostanols
Tobari, Akihiko,Miyamae, Hiroshi,Nagasawa, Akira,Koyanagi, Junichi,Kawase, Masami,Saito, Setsuo
, p. 1745 - 1764 (2007/10/03)
The reaction of 3-O-acetylsarsasapogenin (7), which has no hydroxyl group susceptible to glycosylation, with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (5) in the presence of a mixed catalyst, Hg(CN)2 and HgBr2, caused by clea
SYNTHESIS OF TIGOGENYL β-O-CELLOBIOSIDE HEPTAACETATE AND GLYCOSIDE TETRAACETATE VIA SCHMIDT'S TRICHLOROACETIMIDATE METHOD; SOME NEW OBSERVATIONS.
Urban, Frank J.,Moore, Bernard S.,Breitenbach, Ralph
, p. 4421 - 4424 (2007/10/02)
In studying the synthesis of tigogenyl β-O-cellobioside 1 via the trichloroacetimidate method of Schmidt, cesium carbonate was found to be an efficient reagent for the synthesis of peracetylated disaccharide α-trichloroacetimidates.Zinc bromide was superior to BF3*Et2O for coupling these disaccharide α-trichloroacetimidates with the steroid tigogenin.
Intramolecular Hydrogen Abstraction. Hypervalent Organoiodine Compounds, Convenient Reagents for Alkoxyl Radical Generation
Armas, Pedro de,Concepcion, Jose I.,Francisco, Cosme G.,Hernandez, Rosendo,Salazar, Jose A.,Suarez, Ernesto
, p. 405 - 411 (2007/10/02)
The photolyses of 5α-cholestane-3β,6β-diol 3-acetate (1), 5α-cholestan-2β-ol (4), 5α-cholestan-4β-ol (8), (20R)-pregn-5-ene-3β,20-diol 3-acetate (19), (20S)-pregn-5-ene-3β,20-diol 3-acetate (21), and dihydrotigogenin 3-acetate (25) in the presence of iodine and various hypervalent organoiodine compounds lead to alkoxyl radicals which undergo intramolecular hydrogen abstraction to produce, in most cases, 1,4-iodohydrins and tetrahydrofuran derivatives.
