6802-76-2Relevant academic research and scientific papers
Novel starch-polyalkane composite materials
Hardy,Clark,Rhodes,Wilson
, p. 335 - 336 (2001)
The polymerisation of dibromoalkanes adsorbed in potato starch leads to a novel class of hydrophobic starch-polyalkane composite materials with very high capacity for surface derivitisation.
Late-Stage Intermolecular Allylic C-H Amination
Clark, Joseph R.,Dixon, Charlie F.,Feng, Kaibo,Han, Wei,Ide, Takafumi,Koch, Vanessa,Teng, Dawei,Wendell, Chloe I.,White, M. Christina
supporting information, p. 14969 - 14975 (2021/10/01)
Allylic amination enables late-stage functionalization of natural products where allylic C-H bonds are abundant and introduction of nitrogen may alter biological profiles. Despite advances, intermolecular allylic amination remains a challenging problem due to reactivity and selectivity issues that often mandate excess substrate, furnish product mixtures, and render important classes of olefins (for example, functionalized cyclic) not viable substrates. Here we report that a sustainable manganese perchlorophthalocyanine catalyst, [MnIII(ClPc)], achieves selective, preparative intermolecular allylic C-H amination of 32 cyclic and linear compounds, including ones housing basic amines and competing sites for allylic, ethereal, and benzylic amination. Mechanistic studies support that the high selectivity of [MnIII(ClPc)] may be attributed to its electrophilic, bulky nature and stepwise amination mechanism. Late-stage amination is demonstrated on five distinct classes of natural products, generally with >20:1 site-, regio-, and diastereoselectivity.
Synthesis of spiro[cycloalkane-pyridazinones] with high Fsp3 character
Für, Csilla Sepsey,Riszter, Gergo,Gerencsér, János,Szigetvári, áron,Dékány, Miklós,Hazai, László,Keglevich, Gy?rgy,B?lcskei, Hedvig
, p. 731 - 744 (2020/06/22)
Background: Nowadays, in course of the drug design and discovery much attention is paid to the physicochemical parameters of a drug candidate, in addition to their biological activity. Disadvantageous physicochemical parameters can hinder the success of a drug candidate. Objective: Lovering et al. introduced the Fsp3 character as a measure of carbon bond saturation, which is related to the physicochemical paramethers of the drug. The pharmaceutical research focuses on the synthesis of compounds with high Fsp3 character. Method: To improve the physicochemical properties (clogP, solubility, more advantageous ADME profile, etc.) of drug-candidate molecules one possibility is the replacement of all-carbon aromatic systems with bioisoster heteroaromatic moieties, e.g. with one or two nitrogen atom containing systems, such as pyridines and pyridazines, etc. The other option is to increase the Fsp3 character of the drug candidates. Both of these aspects were considered in the design the new spiro[cycloalkanepyridazinones], the synthesis of which is described in the present study. Results: Starting from 2-oxaspiro[4.5]decane-1,3-dione or 2-oxaspiro[4.4]nonane-1,3-dione, the corresponding ketocarboxylic acids were obtained by Friedel-Crafts reaction with anisole or veratrole. The ketocarboxylic acids were treated by hydrazine, methylhydrazine or phenylhydrazine to form the pyridazinone ring. N-Alkylation reaction of the pyridazinones resulted in the formation of further derivatives with high Fsp3 character. Conclusion: A small compound library was obtained incorporating compounds with high Fsp3 characters, which predicts advantageous physico-chemical parameters (LogP, ClogP and TPSA) for potential applications in medicinal chemistry.
Overcoming Selectivity Issues in Reversible Catalysis: A Transfer Hydrocyanation Exhibiting High Kinetic Control
Bhawal, Benjamin N.,Ehinger, Christian,Morandi, Bill,Reisenbauer, Julia C.
supporting information, p. 10914 - 10920 (2020/07/13)
Reversible catalytic reactions operate under thermodynamic control, and thus, establishing a selective catalytic system poses a considerable challenge. Herein, we report a reversible transfer hydrocyanation protocol that exhibits high selectivity for the thermodynamically less favorable branched isomer. Selectivity is achieved by exploiting the lower barrier for C-CN oxidative addition and reductive elimination at benzylic positions in the absence of a cocatalytic Lewis acid. Through the design of a novel type of HCN donor, a practical, branched-selective, HCN-free transfer hydrocyanation was realized. The synthetically useful resolution of a mixture of branched and linear nitrile isomers was also demonstrated to underline the value of reversible and selective transfer reactions. In a broader context, this work demonstrates that high kinetic selectivity can be achieved in reversible transfer reactions, thus opening new horizons for their synthetic applications.
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.
Preparation method of 1-cyanocyclohexyl acetonitrile
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Paragraph 0009; 0033-0034; 0036-0037; 0039-0040; 0045-0046, (2020/07/08)
The invention provides a method for preparing 1-cyanocyclohexyl acetonitrile by a 'one-pot method', which mainly comprises the following steps: reacting cyclohexanone with alkyl cyanoacetate in the presence of weak base salt and optional acid in a proper organic solvent; after the reaction is completed, adding cyanide, water and a phase transfer catalyst into the reaction system without treatment,and continuing the reaction to obtain 1-cyanocyclohexyl acetonitrile. According to the 1-cyanocyclohexyl acetonitrile obtained by the method, the purity and yield of the product are greatly improved,and the method is low in production cost, simple to operate and suitable for industrial production.
Distal γ-C(sp3)?H Olefination of Ketone Derivatives and Free Carboxylic Acids
Fan, Zhoulong,Park, Han Seul,Yu, Jin-Quan,Zhu, Ru-Yi
supporting information, p. 12853 - 12859 (2020/06/10)
Reported herein is the distal γ-C(sp3)?H olefination of ketone derivatives and free carboxylic acids. Fine tuning of a previously reported imino-acid directing group and using the ligand combination of a mono-N-protected amino acid (MPAA) and an electron-deficient 2-pyridone were critical for the γ-C(sp3)?H olefination of ketone substrates. In addition, MPAAs enabled the γ-C(sp3)?H olefination of free carboxylic acids to form diverse six-membered lactones. Besides alkyl carboxylic acids, benzylic C(sp3)?H bonds also could be functionalized to form 3,4-dihydroisocoumarin structures in a single step from 2-methyl benzoic acid derivatives. The utility of these protocols was demonstrated in large scale reactions and diversification of the γ-C(sp3)?H olefinated products.
Prolinamide functionalized polyacrylonitrile fiber with tunable linker length and surface microenvironment as efficient catalyst for Knoevenagel condensation and related multicomponent tandem reactions
Zhu, Hai,Xu, Gang,Du, Huimin,Zhang, Chenlu,Ma, Ning,Zhang, Wenqin
, p. 217 - 229 (2019/05/16)
A series of new prolinamide polyacrylonitrile fiber catalysts with tunable length of alkyl linker and different linker group were prepared by covalent bonding for the first time and well characterized by mechanical strength, FT-IR, XRD, EA, TGA, SEM and water contact angel. The catalytic activities of these fiber catalysts were evaluated in Knoevenagel condensation and one-pot Knoevenagel-Michael multicomponent tandem reactions to synthesize α, β-unsaturated nitrile and 2-amino-4H-chromene derivatives in water. The result show that the suitable linker length attaching amines to fiber matrix as well as the constructed hydrophobic microenvironment by linker group within the surface layers of fiber materials effectively promotes the reactions. In addition, the good swollen capacity of fiber in solvent ensure that the reaction proceed well. Fiber catalyst PANPA?2F modified by prolinamide with a C2 alkyl chain exhibited the best catalytic performance and can be easily recovered and reused for at least ten consecutive cycles without significant loss of catalytic activity and active sites leaching.
Amino Acid Amide based Ionic Liquid as an Efficient Organo-Catalyst for Solvent-free Knoevenagel Condensation at Room Temperature
Burate, Pralhad A.,Javle, Balasaheb R.,Desale, Pranjal H.,Kinage, Anil K.
, p. 2368 - 2375 (2019/06/17)
Abstract: Ionic liquids of amino acid amide were synthesized and used as an efficient catalyst for solvent-free Knoevenagel condensation. Synthesized ionic liquids are an environmentally benign, inexpensive, metal free and plays the dual role of solvent as well as an efficient catalyst for Knoevenagel condensation. A wide range of aliphatic, aromatic and heteroaromatic aldehydes easily undergo condensation with malononitrile and ethyl cyanoacetate. The reaction proceeds at room temperature without using any organic solvent and is very fast with good to excellent yield. Additionally, the catalyst is easily separable and recyclable without loss of activity. Graphic Abstract: [Figure not available: see fulltext.].
Vanadium-Catalyzed Condensation of Ethyl Cyanoacetate with Ketones
Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
, p. 403 - 409 (2018/04/24)
Vanadium compounds and complexes activated by pyridine or morpholine catalyze condensation of ethyl cyanoacetate with ketones and aldehydes leading to alkylidenecyanoacetates in 75–100% yield.
