1232-89-9Relevant articles and documents
General methodologies toward cis-fused quinone sesquiterpenoids. enantiospecific synthesis of the epi-Ilimaquinone core featuring Sc-catalyzed ring expansion
Kaplan, Hilan Z.,Rendina, Victor L.,Kingsbury, Jason S.
, (2017/07/05)
A stereocontrolled approach to the cis-decalin framework of clerodane diterpenes and biologically active quinone sesquiterpenes is reported. Starting from an inexpensive optically pure tetrahydroindanone, Birch reductive alkylation builds two new contiguous chiral centers—one of which is quaternary and all-carbon-substituted. Also featured is a highly regioselective diazoalkane—carbonyl homologation reaction to prepare the 6,6-bicyclic skeleton. Therein, the utility of Sc(OTf)3 as a mild catalyst for formal 1C insertion in complex settings is demonstrated.
Intramolecular γ-hydroxylations of nonactivated C-H bonds with copper complexes and molecular oxygen
Schoenecker, Bruno,Zheldakova, Tatjana,Lange, Corinna,Guenther, Wolfgang,Goerls, Helmar,Bohl, Martin
, p. 6029 - 6042 (2007/10/03)
Copper(I) complexes incorporating the isomeric bidentate ligands IMPY (iminomethyl-2-pyridines) or AMPY (aminomethylene-2-pyridines) are quite unusual in their ability to bind and activate molecular oxygen. Using these complexes, hydroxylations of nonactivated CH, CH2, or CH3 groups in the γ-position in relation to the imino-nitrogen atom, and with a specific orientation of one H atom with respect to the binuclear Cu-O species, can be achieved in synthetically useful yields. Through mechanistic studies employing conformationally well-defined molecules (for example, cyclic isoprenoids), coupled with solid-state X-ray structure analyses and force-field calculations, we postulate a seven-membered transition state for this reaction in which six atoms lie approximately in a plane. This plane is defined by the positions of the lone pairs on the nitrogen atoms, as well as the copper and the oxygen atoms. For a successful hydroxylation, one hydrogen atom should be located close to this plane. Prediction of the stereochemical course of these reactions is possible based on a simple geometrical criterion. The convenient introduction of IMPY and AMPY groups as auxiliaries into oxo and primary amino compounds and the simple hydrolysis after the hydroxylation procedure has allowed the synthesis of 3-hydroxy-1-oxo and 3-hydroxy-1-amino compounds. If desired, the 3-hydroxy-1-IMPY and -1-AMPY compounds can be reduced with NaBH4 to obtain 3-hydroxy-1-aminomethylpyridines. For a successful hydroxylation procedure, the method employed for the synthesis of the CuI complexes is very important. Starting either from CuI salts or from CuII salts with a subsequent reduction with benzoin/triethylamine may turn out to be the better way, depending on the ligand and the molecular structure.
Synthesis and receptor-binding examinations of the normal and 13-epi-D-homoestrones and their 3-methyl ethers
Woelfling, Janos,Mernyak, Erzsebet,Frank, Eva,Falkay, George,Marki, Arpad,Minorics, Renata,Schneider, Gyula
, p. 277 - 288 (2007/10/03)
An effective epimerization of the normal estrone 3-methyl and 3-benzyl ethers by using o-phenylenediamine and AcOH made the possibility for facile entry into the 13α-estrone series. Combination of this synthetic methodology with an isolation step carried out by means of the Girard-P reagent, the corresponding ethers of 13-epi-estrone were obtained in excellent yields. The 3-hydroxy and 3-methoxy D-homoestrone derivatives in both the normal and the 13α-estrone series were then synthesized and tested in vitro in a radioligand-binding assay. The estrogen receptor recognizes these compounds, but their relative binding affinities (RBAs) are lower than that of the reference compound 3,17β-estradiol. The progesterone receptor-binding affinities of the four D-homo derivatives were also tested showing low values for 13α-D-homoestrone and its 3-methyl ether. Pharmacologically, these 13α-D-homoestrone derivatives are estrogen receptor-selective molecules.
Synthesis Based on Cyclohexadienes. V. A New Approach to the Synthesis of A-Ring Aromatic Steroids: a Formal Total Synthesis of (+/-)-Estrone
Rao, G. S. R. Subba,Banerjee, D. K.,Devi, L. Uma,Sheriff, Uma
, p. 187 - 203 (2007/10/02)
A new strategy for the construction of A-ring aromatic steroids which resulted in the formal total synthesis of estrone is described.Thus reaction of the adduct (9), obtained from 1-methoxy-4-methylcyclohexa-1,4-diene and acrolein, with 3-(m-methoxyphenyl
