1225-43-0Relevant academic research and scientific papers
Ultrasound assisted zinc reactions in synthesis 2. A new Clemmensen-type reduction
Salvador,Sa E Melo,Campos Neves
, p. 361 - 362 (1993)
A mild and efficient method is described for the reduction of carbonyls to methylene groups. Under ultrasonic irradiation, deoxygenation of 3-oxosteroids with zinc dust in acetic acid or acetic acid/water was achieved in 15 minutes. The observed selectivity at C-3 in the presence of 17- and 20-oxo groups is discussed.
ANTI-CANCER NUCLEAR HORMONE RECEPTOR-TARGETING COMPOUNDS
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Page/Page column 237; 238, (2019/12/04)
The disclosure relates to anti-cancer compounds derived from nuclear steroid receptor binders, to products containing the same, as well as to methods of their use and preparation.
Identification of a fossil sterane biomarker in crude oil - An androstane with a modified carbon skeleton
Bender, Matthias,Schmidtmann, Marc,Rullkoetter, Juergen,Summons, Roger E.,Christoffers, Jens
, p. 5934 - 5945 (2013/09/23)
Three constitutional isomers of androstane were prepared for comparison with three unknown fossil C19H32 organic biomarkers ("19A", "19B", and "19C" in elution order in geological samples from Oman. 3β-Methyl-A-nor-androstane was pre
PROGESTERONE RECEPTOR ANTAGONISTS AND USES THEREOF
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Page/Page column 39, (2011/11/30)
The present invention relates to a compound of formula (I): for its use as progesterone receptor antagonist, in particular for its use for the prevention and/or the treatment of cancer or uterine pathologies.
Factors Affecting the Facial Selectivity in the Hydroboration of Steroidal Δ5-Enes
Arantes, Simone F.,Hanson, James R.,Liman, Mansur D.,Manickavasagar, Revathy,Uyanik, Cavit
, p. 2381 - 2397 (2007/10/03)
A comparison between the facial selectivity observed in the hydroboration of some androst-5-enes and B-norandrost-5-enes does not parallel the differences between the calculated force field energies of α- and β-cyclobutane models suggesting that in this case the facial selectivity is not determined by the four centre transition state but by the ease of formation of the initial ?-complexes between the alkene and the borane.
The Stereochemistry of an Elimination Reaction accompanying the Hydroboration of a Steroidal Allylic Alcohol
Hanson, James R.,Liman, Mansur D.,Uyanik, Cavit
, p. 126 - 127 (2007/10/03)
Deuterium labelling studies have shown that the facile elimination of the 5β-hydroxy group observed in the course of hydroboration of a 5β-hydroxyandrost-3-ene may involve a trans diaxial borane-borinate elimination coupled with a syn transfer of hydrogen from the borinate.
Desulfurization with Nickel and Cobalt Boride: Scope, Selectivity, Stereochemistry, and Deuterium-Labeling Studies
Back, Thomas G.,Baron, Denise L.,Yang, Kexin
, p. 2407 - 2413 (2007/10/02)
A variety of organosulfur compounds containing alkylthio and arylthio groups underwent reductive desulfurization under notably mild conditions when treated with nickel boride, generated in situ from nickel chloride hexahydrate and sodium borohydride in methanol-THF (3:1).Phenyl, chloro, and ester groups are not reduced under these conditions, while iodo, bromo, nitrile, aldehyde, ketone, cyclopropane, and olefinic functions are reduced either completely or partially.Deuterium-labeling studies indicate that the hydrogen that is incorporated into the product originates from both the sodium borohydride and the protic solvent, suggesting the intermediacy of dihydrogen.The epimers 3α- and 3β-(phenylthio)cholestane afforded 3α- and 3β-deuteriocholestane, respectively, demonstrating that the reaction proceeds with retention of configuration.The method may thus be employed for the stereospecific preparation of deuterated products from organosulfur compounds.Arguments are presented in support of a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate.
THE BIOTRANSFORMATION OF SOME STEROIDS BY CEPHALOSPORIUM APHIDICOLA
Hanson, James R.,Nasir, Habib
, p. 831 - 834 (2007/10/02)
Hydroxylation of 5α-androstane-3-one and 3,6-dione by C. aphidicla takes place at C-17β and, in the case of the latter, at C-5α.The fungus reduces 5α-androstan-17-one and the 3,17-dione to the 17β-alcohols. Key Word Index - Cephalosporium aphidicola; fungus; microbiological hydroxylation; steroids.
Selective Reduction of Aryl Halides and α,β-Unsaturated Esters with Sodium Borohydride-Cuprous Chloride in Methanol and Its Application to Deuterium Labeling
Narisada, Masayuki,Horibe, Isao,Watanabe, Fumihiko,Takeda, Ken'ichi
, p. 5308 - 5313 (2007/10/02)
A reducing system, NaBH4-Cu2Cl2/MeOH, was developed for dehalogenation of aryl halides, conjugate reduction of α,β-unsaturated esters, and deuterium labeling in a chemo- and regioselective manner.These reactions proceeded without reduction of isolated olefins.The Cu2Cl2 is assumed to function as the catalyst which generates a transient species of copper hydride as an active reducing agent, on contact with NaBH4.Deuterium-labeling studies indicated that (i) the hydrogen which is transferred to the 4-position of methyl 4-iodobenzoate originates from MeOH and (ii) thehydrogens which were transferred to the α- and β-positions of the conjugated ester originate from MeOH and NaBH4, respectively.
The Predominance and Quantification of Steric Effects in the Solvolysis of Secondary Aliphatic Esters
Schneider, Hans-Joerg,Becker, Norman,Schmidt, Guenther,Thomas, Fred
, p. 3602 - 3607 (2007/10/02)
The solvolysis rates of 35 tosylates in hexafluoroisopropyl alcohol are measured and compared to MM2 calculated strain energies, ΔSI, between weighted sp3 states and the lowest sp2 state.For unhindered (pseudo)equatorially substituted cycloalkyl tosylates a linear correlation, free from ambiguities involved, e.g., with the leaving group simulation, is obtained which shows a sensitivity of m=1.04+/-0.05, indicating an extremely late transition state or limiting behavior.Based on the corresponding equation, it is shown that alkyl substituents in the γ- and in the β-position do not promote significant rate increases, even when there is an antiperiplanar disposition between the leaving group and a migrating β-methyl substituent.Instead, these substituents can lead to substantial ΔG* increase (by up to 5 kcal/mol in comparison to the ΔSI prediction), which is related to steric hindrance of solvation and/or hindrance for elimination. 17-(Tosyloxy)androstanes show extremely large epimeric rate ratios of>30000; these are not due to anchimeric assistance but only to the exceedingly slow reaction of the hindered 17β isomer, whereas the fast reaction of the 17α tosylate (e.g. 200 times higher than cyclopentyl tosylate) is in line with the ΔSI calculation. endo-Bicycloheptane esters show evidence for steric hindrance; exo-norbornyl tosylate has, however, a ΔG* value lower by 4 kcal/mol than predicted. ks/kc values, obtained by rate comparison in 80percent ethanol and 97percent HFIP, vary between 0.5 and 300, mainly as a result of different steric hindrance to rearside nucleophilic subnstitution
