2262-52-4Relevant academic research and scientific papers
Ball-Milling-Enabled Reactivity of Manganese Metal**
Bolt, Robert R. A.,Browne, Duncan L.,Howard, Joseph L.,Khan, Adam,Magri, Giuseppina,Morrill, Louis C.,Nicholson, William I.,Richards, Emma,Seastram, Alex C.
supporting information, p. 23128 - 23133 (2021/09/20)
Efforts to generate organomanganese reagents under ball-milling conditions have led to the serendipitous discovery that manganese metal can mediate the reductive dimerization of arylidene malonates. The newly uncovered process has been optimized and its mechanism explored using CV measurements, radical trapping experiments, EPR spectroscopy, and solution control reactions. This unique reactivity can also be translated to solution whereupon pre-milling of the manganese is required.
Johnson-Corey-Chaykovsky fluorocyclopropanation of double activated alkenes: Scope and limitations
Kazia, Armands,Melngaile, Renate,Mishnev, Anatoly,Veliks, Janis
supporting information, p. 1384 - 1388 (2020/03/03)
Johnson-Corey-Chaykovsky fluorocyclopropanation of double activated alkenes utilizing S-monofluoromethyl-S-phenyl-2,3,4,5-tetramethylphenylsulfonium tetrafluoroborate is an efficient approach to obtain a range of monofluorocyclopropane derivatives. So far, fluoromethylsulfonium salts have displayed the broadest scope for direct fluoromethylene transfer. In contrast to more commonly used fluorohalomethanes or freon derivatives, diarylfluoromethylsulfonium salts are bench stable, easy-to use reagents useful for the direct transfer of a fluoromethylene group to alkenes giving access to the challenging products-fluorocyclopropane derivatives. Interplay between the reactivity of the starting materials and stability of the fluorocyclopropanes formed determines the outcome of the process.
Solvent-Free FeCl3-Assisted Electrophilic Fluorine-Catalyzed Knoevenagel Condensation to Yield α,β-Unsaturated Dicarbonyl Compounds and Coumarins
Yang, Lu,Zhu, Jiang,Xie, Fukai,Peng, Xiaoshi,Lin, Bin,Liu, Yongxiang,Cheng, Maosheng
, p. 1053 - 1060 (2019/09/06)
A highly environmentally friendly procedure was developed for the Knoevenagel condensation of aromatic aldehydes with diethyl malonate in the presence of FeCl3 and N-fluorobenzenesulfonimide as a source of electrophilic fluorine under solvent-free conditions. The scope of the reaction was explored using commercially available substrates. The reaction with substituted salicylaldehydes afforded the corresponding coumarin derivatives which attract interest due to their potential medicinal importance.
Metal free biomimetic deaminative direct C-C coupling of unprotected primary amines with active methylene compounds
Ghosh, Santanu,Jana, Chandan K.
supporting information, p. 10153 - 10157 (2019/12/26)
An unprecedented direct C-C coupling reaction of unprotected primary amines with active methylene compounds is reported. The reaction involves a biomimetic deamination of amines which was achieved under conditions free of metallic reagents and strong oxidizing agents. A wide range of primary amines was reacted with different active methylene compounds to provide structurally diverse trisubstituted alkenes and dihydropyridines. A kinetic study revealed an activation barrier of 10.1 kcal mol-1 for the conversion of a key intermediate of the reaction.
Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate
Coutant, Eloi P.,Hervin, Vincent,Gagnot, Glwadys,Ford, Candice,Baatallah, Racha,Janin, Yves L.
supporting information, p. 2853 - 2860 (2018/11/26)
We have explored here the scope of the age-old diethyl malonate-based accesses to α-amino esters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered. The synthetic modifications of some of the intermediates - using Suzuki-Miyaura coupling or cycloadditions - before undertaking the oximation step - provided accesses to further α-amino esters. Moreover, other pathways to α-hydroxyimino esters were explored including an attempt to improve the cycloadditions between ethyl β-bromo-α-hydroxyiminocarboxylate and various alkylfuranes.
Enantioselective Desymmetrization of Glutarimides Catalyzed by Oxazaborolidines Derived from cis-1-Amino-indan-2-ol
Kutama, Ibrahim U.,Jones, Simon
, p. 11468 - 11479 (2015/12/04)
Enantioselective reductive desymmetrization of glutarimides has been achieved employing an oxazaborolidine catalyst derived from cis-1-amino-indan-2-ol. The reaction was found to proceed through a stereoablative process that upgraded the enantioselectivity of an intermediate hydroxy-lactam. The reaction was generally tolerant of a number of substituents in the 4-position, giving enantiomeric excesses of greater than 82%.
Design and synthesis of 6-oxo-1,4,5,6-tetrahydropyrimidine-5-carboxylate derivatives as neuraminidase inhibitors
Lou, Jun,Yang, Xiaoyan,Rao, Zhigang,Qi, Wenwen,Li, Jinhui,Wang, Haiyu,Li, Yuxi,Li, Jinping,Wang, Zhiming,Hu, Xianming,Liu, Peng,Hong, Xuechuan
, p. 466 - 473 (2014/07/21)
A series of 6-oxo-1,4,5,6-tetrahydropyrimidine-5-carboxylate derivatives were prepared to evaluate their ability of inhibiting neuraminidase (NA) of influenza A virus. All the compounds were synthesized in good yields starting from aldehyde by using a suitable synthetic strategy, which showed moderate inhibitory activity against influenza A NA. Compound 6g exhibited the strongest inhibitory activity against influenza virus A NA (IC50 = 17.64 μM), which indicated pyrimidine ring could be used as a core structure to design novel influenza NA inhibitors.
Chiral-Zn(NTf2)2-complex-catalyzed diastereo- and enantioselective direct conjugate addition of arylacetonitriles to alkylidene malonates
Yao, Jingjing,Liu, Xiaohua,He, Peng,Zhu, Yin,Lian, Xiangjin,Lin, Lili,Feng, Xiaoming
supporting information, p. 16424 - 16430 (2013/12/04)
Chiral N,N′-dioxide/Zn(NTf2)2 complexes were demonstrated to be highly effective in the direct asymmetric conjugate addition of arylacetonitriles to alkylidene malonates under mild conditions. A wide range of substrates were tolerated to afford their corresponding products in moderate-to-good yields with high diastereoselectivities (82:18->99:1 d.r.) and enantioselectivities (81-99 % ee). The reactions performed well, owing to the high Lewis acidity of the metal triflimidate and a ligand-acceleration effect. The N,N′-dioxide also benefited the deprotonation process as a Bronsted base. The catalytic reaction could be performed on the gram-scale with retention of yield, diastereoselectivity, and enantioselectivity. The products that contained functional groups were ready for further manipulation. In addition, a possible catalytic model was proposed to explain the origin of the asymmetric induction. Copyright
Synthesis and anti-tumor activity of novel ethyl 3-aryl-4-oxo-3,3a,4,6- tetrahydro-1H-furo[3,4-c]pyran-3a-carboxylates
Wang, Tiantian,Liu, Jia,Zhong, Hanyu,Chen, Huan,Lv, Zhiliang,Zhang, Yikai,Zhang, Mingfeng,Geng, Dongping,Niu, Chunjuan,Li, Yongmei,Li, Ke
scheme or table, p. 3381 - 3383 (2011/06/24)
A series of ethyl 3-aryl-4-oxo-3,3a,4,6-tetrahydro-1H-furo[3,4-c]pyran-3a- carboxylates were prepared through the metal-catalyzed domino reaction of alkylidene malonates and 1,4-butynediol under a one-pot reaction condition at room temperature. Their in vitro anti-proliferative activities were subsequently evaluated in A549, QGY and HeLa cells. The majority of the compounds showed potent anti-tumor activity against HeLa cells. In particular, compound 3l was the most potent compound with IC50 value of 5.4 μM. For the first time, the X-ray structure of the anti-tumor ethyl 3-aryl-4-oxo-3,3a,4,6- tetrahydro-1H-furo[3,4-c]pyran-3a-carboxylates is determined.
Preparation of Some Chromans Substituted at the 3- or 4-Position by an Aryl or Benzyl Group, by the Rhodium-catalysed Intramolecular Nucleophilic Substitution of the Corresponding 3-(2-Fluorophenyl)propanols
Houghton, Roy P.,Shervington, Leroy A.
, p. 1872 - 1892 (2007/10/02)
The bis(hexafluorophosphate) salt of the (η5-ethyltetramethylcyclopentadienyl)(η6-benzene)rhodium(III) cation has been used as a catalyst to prepare 3-phenyl-, 3-(4-methoxyphenyl)-, 3-(4-nitrophenyl)-, and 4-benzylchroman by cyclisation of the corresponding substituted 3-(2-fluorophenyl)-propanols in nitromethane-acetone solution. 3-Phenyl-4-hydroxymethylchroman and 3-hydroxymethyl-4-phenylchroman were prepared similarly.An attempt to prepare a bis(chroman) by a double cyclisation with 2-propane-1,3-diol afforded only the monochroman, 4-(2-fluorophenyl)-3-hydroxymethylchroman.Under the conditions of the cyclisation, the erythro and threo forms of 1,4-di(2-fluorophenyl)-butane-2,3-diol afforded only the corresponding 1,3-dioxolanes as the result of the diols reacting with the acetone used as cosolvent.The 1H n.m.r. spectra of the 3-substituted and 3,4-disubstituted chromans which have been prepared are consistent with the heterocyclic ring being in the half-chair conformation (6).
