858-98-0Relevant articles and documents
Synthesis of Various Bridged Ring Systems via Rhodium-Catalyzed Bridged (3+2) Cycloadditions
He, Yu-Tao,Li, Li-Xuan,Lin, Xiaohong,Hou, Bao-Long,Li, Chuang-Chuang
supporting information, p. 186 - 190 (2022/01/11)
Here, we describe the rhodium-catalyzed bridged (3+2) cycloaddition cascade reactions of N-sulfonyl-1,2,3-triazoles, which allowed the efficient diastereoselective construction of various functionalized and synthetically challenging bridged ring systems. This simple, direct transformation had a broad substrate scope and excellent functional group tolerance. The highly strained polycyclic bicyclo[2.2.2]octa[b]indole core of fruticosine was synthesized efficiently using this methodology.
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
supporting information, p. 16865 - 16873 (2021/10/20)
Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
Stereoselective Dehydroxyboration of Allylic Alcohols to Access (E)-Allylboronates by a Combination of C-OH Cleavage and Boron Transfer under Iron Catalysis
Su, Wei,Wang, Ting-Ting,Tian, Xia,Han, Jian-Rong,Zhen, Xiao-Li,Fan, Shi-Ming,You, Ya-Xin,Zhang, Yu-Kun,Qiao, Rui-Xiao,Cheng, Qiushi,Liu, Shouxin
supporting information, p. 9094 - 9099 (2021/11/30)
Iron-catalyzed direct SN2′ dehydroxyboration of allylic alcohols has been developed to access (E)-stereoselective allylboronates. Allylic alcohols with diverse structures and functional groups, especially derived from natural products, underwent smooth transformation. The six-membered ring transition state formed by allylic alcohols and iron-boron intermediate was indicated to be the key component involved in transfer of the boron group, activation of the C-OH bond, and control of the stereoselectivity.
Allylboronates from vinyl triflates and α-chloroboronates by reductive nickel catalysis
Qiao, Jin-Bao,Zhao, Zhen-Zhen,Zhang, Ya-Qian,Yin, Kai,Tian, Zhi-Xiong,Shu, Xing-Zhong
supporting information, p. 5085 - 5089 (2020/07/16)
Allylboronates are unique building blocks widely used in organic synthesis, but the construction of cyclic allylboranates remains a challenging subject. We demonstrate here a mild and efficient access to this type of compound through the cross-electrophile coupling of vinyl triflates and α-chloroboronates. The reaction proceeded with a good substrate scope and good functional group compatibility. The ready availability of vinyl triflates from ketones, as well as the rich chemistry of allylboranates, makes our method suitable for the divergent modification of biologically active compounds. Preliminary mechanistic studies revealed that α-chloroboronates were activated via a radical process.
Design and synthesis of dansyl-labeled inhibitors of steroid sulfatase for optical imaging
Barbeau, Xavier,Lambert, Jean-Philippe,Ngueta Djiemeny, Adrien,Poirier, Donald,Roy, Jenny,Maltais, René
, (2020/03/05)
Steroid sulfatase (STS) is an important enzyme regulating the conversion of sulfated steroids into their active hydroxylated forms. Notably, the inhibition of STS has been shown to decrease the levels of active estrogens and was translated into clinical t
Highly-chemoselective step-down reduction of carboxylic acids to aromatic hydrocarbons: Via palladium catalysis
Liu, Chengwei,Qin, Zhi-Xin,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
, p. 5736 - 5742 (2019/06/18)
Aryl carboxylic acids are among the most abundant substrates in chemical synthesis and represent a perfect example of a traceless directing group that is central to many processes in the preparation of pharmaceuticals, natural products and polymers. Herein, we describe a highly selective method for the direct step-down reduction of carboxylic acids to arenes, proceeding via well-defined Pd(0)/(ii) catalytic cycle. The method shows a remarkably broad substrate scope, enabling to direct the classical acyl reduction towards selective decarbonylation by a redox-neutral mechanism. The utility of this reaction is highlighted in the direct defunctionalization of pharmaceuticals and natural products, and further emphasized in a range of traceless processes using removable carboxylic acids under mild, redox-neutral conditions orthogonal to protodecarboxylation. Extensive DFT computations were conducted to demonstrate preferred selectivity for the reversible oxidative addition and indicated that a versatile hydrogen atom transfer (HAT) pathway is operable.
Discovery of novel steroidal histamine H3 receptor antagonists/inverse agonists. Part 2. Versatile steroidal carboxamide derivatives
Ledneczki, István,Némethy, Zsolt,Tapolcsányi, Pál,éles, János,Greiner, István,Gábor, Eszter,Varga, Balázs,Balázs, Ottilia,Román, Viktor,Lévay, Gy?rgy,Mahó, Sándor
supporting information, (2019/09/06)
To further proceed with our previous work, novel steroid-based histamine H3 receptor antagonists were identified and characterized. Using an ‘amine-to-amide’ modification strategy at position 17, in vitro and in vivo potent monoamino steroid derivatives were found during the lead optimization. Usage of the non-basic amide moiety resulted in beneficial effects both in activity and selectivity. The 15α-carboxamido derivative 10 was not only highly active at human and rat H3 receptors, but also showed negligible activity at rat muscarinic receptors. Furthermore, it proved to be considerably stable in human and rat microsomes and showed significant in vivo potency in the pharmacodynamic rat dipsogenia test and in the water-labyrinth cognitive model. Based on all of these considerations, compound 10 was appointed to be a preclinical candidate.
Synthesis of unprecedented steroidal spiro heterocycles as potential antiproliferative drugs
Romero-Hernández, Laura L.,Merino-Montiel, Penélope,Meza-Reyes, Socorro,Vega-Baez, José Luis,López, óscar,Padrón, José M.,Montiel-Smith, Sara
, p. 21 - 32 (2017/11/24)
Herein we report the straightforward preparation of novel conformationally-restricted steroids from trans-androsterone and estrone, decorated with spiranic oxazolidin-2-one or 2-aminooxazoline motifs at C-17 as potential antiproliferative agents. Such unp
Targeting RORs nuclear receptors by novel synthetic steroidal inverse agonists for autoimmune disorders
Dal Prà, Matteo,Carta, Davide,Szabadkai, Gyorgy,Suman, Matteo,Frión-Herrera, Yahima,Paccagnella, Nicola,Castellani, Giulia,De Martin, Sara,Ferlin, Maria Grazia
, p. 1686 - 1704 (2018/02/26)
Designing novel inverse agonists of NR RORγt still represents a challenge for the pharmaceutical community to develop therapeutics for treating immune diseases. By exploring the structure of NRs natural ligands, the representative arotenoid ligands and RORs specific ligands share some chemical homologies which can be exploited to design a novel molecular structure characterized by a polycyclic core bearing a polar head and a hydrophobic tail. Compound MG 2778 (8), a cyclopenta[a]phenantrene derivative, was identified as lead compound which was chemically modified at position 2 in order to obtain a small library for preliminary SARs. Cell viability and estrogenic activity of compounds 7, 8, 19a, 30, 31 and 32 were evaluated to attest selectivity. The selected 7, 8, 19a and 31 compounds were assayed in a Gal4 UAS-Luc co-transfection system in order to determine their ability to modulate RORγt activity in a cellular environment. They were evaluated as inverse agonists taken ursolic acid as reference compound. The potency of compounds was lower than that of ursolic acid, but their efficacy was similar. Compound 19a was the most active, significantly reducing RORγt activity at low micromolar concentrations.
A estrone the raw materials of the impurity and its preparation method and as the standard use of
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Paragraph 0010; 0014; 0015, (2018/01/11)
The invention relates to a novel impurity which is generated in an estrone synthesis process, and a preparation method and application of the novel impurity. The impurity is 17-(4'-phenyl phenyl)-estra-1,3,5(10)-triene-3,17 beta-glycol. The preparation me
