17748-68-4Relevant academic research and scientific papers
Selective synthesis of 14 dehydroestranes
Rasmusson,Arth
, p. 107 - 111 (1973)
The report of the preparation and high androgenic activity of Δ14 19 nortestosterone and its 7α methyl derivative prompted the authors to disclose an alternate synthesis of these compounds. The introduction of the double bond into the 14 position of estranes has been accomplished by acid or base equilibration of an initially formed Δ15 isomer.
Combination of a customized robotic system with a TLC scanner for high-throughput reaction screening
Dinter, Christian,Weinmann, Hilmar,Merten, Claudia,Schuetz, Armin,Blume, Thorsten,Sander, Michael,Harre, Michael,Neh, Harribert
, p. 482 - 487 (2004)
Combination of a new and highly efficient robotic system for high-throughput reaction screening with a thin-layer chromatography (TLC) scanner is described. The system consists of a parallel synthesis robot capable of performing up to several hundred reactions in parallel and a second robot for analytical sample workup, dilution, and TLC-spotting. The automatically prepared TLC plates are analyzed with a modern TLC scanner which gives rapidly semi-quantitative analytical results on the outcome of the single reactions. Several automated chemistry examples clearly demonstrate the high efficiency of this combined system and its superiority compared to more classical approaches, e.g., HPLC analyses.
Synthesis of Cyclic Enones by Allyl-Palladium-Catalyzed α,β-Dehydrogenation
Huang, David,Zhao, Yizhou,Newhouse, Timothy R.
, p. 684 - 687 (2018)
The use of allyl-palladium catalysis for the one-step α,β-dehydrogenation of ketones via their zinc enolates is reported. The optimized protocol utilizes commercially available Zn(TMP)2 as base and diethyl allyl phosphate as oxidant. Notably, this transformation operates under salt-free conditions and tolerates a diverse scope of cycloalkanones.
Copper-Catalyzed Desaturation of Lactones, Lactams, and Ketones under pH-Neutral Conditions
Chen, Ming,Dong, Guangbin
supporting information, p. 14889 - 14897 (2019/10/02)
A copper-catalyzed desaturation method that is suitable for converting lactones, lactams, and cyclic ketones to their α,β-unsaturated counterparts is reported. The reaction does not require strong base/acid or sulfur/selenium reagents and can be carried out through a simple one-step operation. The protocol uses inexpensive catalysts and reagents and exhibits excellent scalability and functional group tolerance. Notably, tert-butyl alcohol is the only stoichiometric byproduct produced, and overoxidation is not observed. The reaction mechanism has been investigated through control experiments, deuterium labeling, radical clock, electron paramagnetic resonance, high-resolution mass spectrometry, and kinetic studies. The data obtained are consistent with a reaction pathway involving reversible α-deprotonation by a Cu(II)-OtBu species followed by further oxidation of the resulting Cu enolate.
Allyl-Palladium-Catalyzed Ketone Dehydrogenation Enables Telescoping with Enone α,β-Vicinal Difunctionalization
Chen, Yifeng,Huang, David,Zhao, Yizhou,Newhouse, Timothy R.
supporting information, p. 8258 - 8262 (2017/06/30)
The telescoping of allyl-palladium catalyzed ketone dehydrogenation with organocuprate conjugate addition chemistry allows for the introduction of aryl, heteroaryl, vinyl, acyl, methyl, and other functionalized alkyl groups chemoselectively to a wide variety of unactivated ketone compounds via their enone counterparts. The compatibility of the dehydrogenation conditions additionally allows for efficient trapping of the intermediate enolate with various electrophiles. The utility of this approach is demonstrated by comparison to several previously reported multistep sequences.
Stereoselective synthesis of some methyl-substituted steroid hormones and their in vitro cytotoxic activity against human gastric cancer cell line MGC-803
Li, Chun,Qiu, Wenwei,Yang, Zhengfeng,Luo, Jian,Yang, Fan,Liu, Mingyao,Xie, Juan,Tang, Jie
experimental part, p. 859 - 869 (2010/10/18)
A series of 3-, 7-, 15-, and 16-methyl-substituted steroid analogs were synthesized via a highly stereoselective 1,6-conjugate addition. Under the catalysis of CuBr, AlMe3 reacted with four steroid dienone precursors to afford either the corresponding α-epimer of C-3 and C-7 methyl-substituted steroids as the major products, and the ratio of α/β was up to 10/1. No β-epimer has been detected for methyl addition at C-16. However, under the same reaction conditions, enantioselective methyl addition at C-15 afforded the 15β-epimer as the major product. The preliminary SAR analysis showed that the methyl substituents at C-7α and C-15β positions lead to a dramatical increase in potency against human gastric cancer cell line MGC-803.
Indole diterpene synthetic studies: Development of a second-generation synthetic strategy for (+)-nodulisporic acids A and B
Smith III, Amos B.,Kuerti, Laszlo,Davulcu, Akin H.,Young, Shin Cho,Ohmoto, Kazuyuki
, p. 4611 - 4620 (2008/02/07)
(Chemical Equation Presented) A second-generation strategy for construction of (+)-nodulisporic acids A and B based on the development of a new, effective modular indole synthesis exploiting a sequential Stille cross-coupling/Buchwald- Hartwig union/cyclization tactic is disclosed. This strategy evolved due to the considerable acid instability of the C(24) hydroxyl group observed in several advanced intermediates during our first-generation approach.
A new modular indole synthesis. Construction of the highly strained CDEF parent tetracycle of nodulisporic acids A and B
Smith III, Amos B.,Kuerti, Laszlo,Davulcu, Akin H.
, p. 2167 - 2170 (2007/10/03)
Construction of the highly strained CDEF parent tetracycle, a structural motif found only in the potent ectoparasiticidal agents (+)-nodulisporic acids A and B and related congeners, has been achieved via a new modular indole synthesis, exploiting a sequential Stille cross-coupling/Buchwald-Hartwig union/cyclization tactic. The new indole synthesis holds the promise of rapid assembly of diverse, highly substituted indoles possessing uncommon substitution patterns.
The fluorous Swern and Corey-Kim reactions: Scope and mechanism
Crich, David,Neelamkavil, Santhosh
, p. 3865 - 3870 (2007/10/03)
Protocols for the efficient preparation of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluoro-8-methanesulfenyloctane and 1,1,1,2,2,3,3,4,4-nonafluoro-6-methanesulfenylhexane (fluorous dimethyl sulfide) and for their oxidation to the corresponding sulfoxides (fluorous dimethyl sulfoxide) are reported. The lower molecular weight sulfoxide, in conjunction with oxalyl chloride and Hunig's base, brings about the oxidation of diversely functionalized primary and secondary alcohols to aldehydes and ketones in excellent yield. The fluorous sulfoxide is efficiently recovered for reuse by a simple continuous fluorous extraction and hydrogen peroxide oxidation protocol. The whole process is odor-free. A deuterium-labeling experiment is used to demonstrate that the oxidations take place via the classical Swern mechanism, i.e. by intramolecular hydride abstraction from a sulfur ylid. Corey-Kim oxidations may be performed with the higher molecular weight fluorous sulfide, although recycling is not as efficient.
D-ring allyl derivatives of 17β- and 17α-estradiols: Chemical synthesis and 13C NMR data
Dionne, Patricia,Ngatcha, Beatrice Tchedam,Poirier, Donald
, p. 674 - 681 (2007/10/03)
We report the 13 C NMR data for 17β-estradiol, 17α-estradiol, and a series of ten 17β- or 17α-estradiol derivatives bearing an allyl group on the D-ring (at C-17, C-16, and C-15 positions). The target 17β-OH estradiol derivatives were synthesized from estrone by well known obtained by a modified Mitsunoba alcohol inversion of the allyl group (17α, 17β, 16α, 16β, and 15β) and two alcohol stereochemistries (17β and 17α) of the D- ring were studied, resulting in an important source of data. The effect of allyl-positioning and alcohol stereochemistry on 13C NMR chemical shifts was also identified, producing important points of comparison for other steriod analogs.
