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Zheyu Luo, Jaewan Ahn, Dong Qin
We report the fabrication of Ag-Pd concave nanocrystals by introducing the Pd(ii) precursor into an aqueous suspension of Ag nanocubes in the presence of cetyltrimethylammonium chloride (CTAC) under ambient conditions. Different from the previously reported work that involved the oxidation of Ag and deposition of Pd at random sites on the surface for the generation of Ag-Pd hollow nanocrystals, we demonstrate that the Cl- ions from CTAC can confine the oxidation of Ag atoms to the side faces of a nanocube while the resultant Pd atoms are deposited on the edges in an orthogonal manner...
March 22, 2019: Nanoscale
Samaresh Chandra Sau, Ruhuai Mei, Julia Struwe, Lutz Ackermann
Electrochemical oxidative C-H/N-H activations with isocyanides have been realized with a versatile cobalt catalyst. The widely applicable cobalt catalysis manifold further enabled electrooxidative C-H/N-H carbonylations with carbon monoxide under ambient conditions. The C-H functionalizations were efficiently realized with ample scope and outstanding functional group tolerance in an user-friendly undivided cell set-up.
March 21, 2019: ChemSusChem
Kuno Schwärzer, Andreas Bellan, Maximilian Zöschg, Konstantin Kargaghiosoff, Paul Knochel
We report the selective addition of organomagnesium reagents to 2,4,6-trichlorophenyl isocyanide leading to magnesiated aldimines which react with Weinreb amides, ketones or carbonates to provide the corresponding carbonyl derivatives after acidic cleavage. This allows an efficient synthesis of 1,2-dicarbonyl compounds ans α-hydroxy ketones.
March 21, 2019: Chemistry: a European Journal
Arefeh Shafie, Maryam Mohammadi-Khanaposhtani, Mehdi Asadi, Nastaran Rahimi, Parviz Rashidi Ranjbar, Jahan B Ghasemi, Bagher Larijani, Mohammad Mahdavi, Hamed Shafaroodi, Ahmad Reza Dehpour
A novel series of 1,2,3-triazolo-benzodiazepine derivatives 6a-o has been synthesized and evaluated in vivo for their anticonvulsant activities using by pentylenetetrazole (PTZ)- and maximal electroshock (MES)-induced seizures in mice. The synthetic approach started with diazotizing 2-aminobenzoic acids 1 to produce 2-azidobenzoic acids 2. Next, reaction of the latter compounds with propargylamine 3, benzaldehyde 4, and isocyanides 5 led to the formation of the title compounds 6a-o, in good yields. All the synthesized compounds exhibited high anticonvulsant activity in the PTZ test, comparable to or better than the standard drug diazepam...
March 20, 2019: Molecular Diversity
Jinxiong Cai, Haijie Bai, Yuan Wang, Xianxiu Xu, Haiming Xie, Jun Liu
A novel base-mediated regioselective [3+2] annulation of active methylene isocyanides with ketenimines has been developed. In the presence of t-BuOK, a wide range of ketenimines readily react with active methylene isocyanides in DMF at 40 °C to afford 1,4,5-trisubstituted imidazoles efficiently.
March 14, 2019: Chemical Communications: Chem Comm
Mohammed Salah Ayoup, Yasmin Wahby, Hamida Abdel-Hamid, El Sayed Ramadan, Mohamed Teleb, Marwa M Abu-Serie, Ahmed Noby
Evasion of apoptosis is a hallmark of cancer. Caspases; the key executors of apoptotic cascade are attractive targets for selective induction of apoptosis in cancer cells. Within this approach, various caspase activators were introduced as lead anticancer agents. In the current study, a new series of multifunctional Passerini products was synthesized and evaluated as potent caspase-dependent apoptotic inducers. The synthetic strategy adopted this isocyanide-based multicomponent reaction to possibly mimic the pharmacophoric features of various lead apoptotic inducers, where a series of α-acyloxy carboxamides was prepared from p-nitrophenyl isonitrile, cyclohexanone and various carboxylic acids...
February 22, 2019: European Journal of Medicinal Chemistry
Zhen Yang, Kun Jiang, Ying-Chun Chen, Ye Wei
A copper-catalyzed protocol has been realized for the rapid assembly of dihydroquinolinones from readily accessible isocyanides and O-benzoyl hydroxylamines. The reactions (10 mol % of CuOAc, 10 mol% of dppe, 3 equiv of PhONa, 30 °C) deliver various structurally interesting dihydroquinolinones in moderate to good yields (up to 76%). The reactions may proceed in a cascade manner involving isocyanide insertion into N-O bond, Mumm-type rearrangement, and intramolecular nucleophilic substitution.
February 26, 2019: Journal of Organic Chemistry
Bryan Tuten, Lies De Keer, Sandra Wiedbrauk, Paul Van Steenberge, Dagmar D'hooge, Christopher Barner-Kowollik
Herein, we introduce an additive free visible light-induced Passerini multicomponent polymerization (MCP) for the generation of high molar mass chains. In place of classical aldehydes (or ketones), highly reactive, in situ photogenerated thioaldehydes are exploited along with isocyanides and carboxylic acids. Prone to side reactions, the thioaldehyde moieties create a complex reaction environment which can be tamed by optimizing the synthesis conditions utilizing stochastic reaction path analysis, highlighting the potential of semi-batch procedures...
February 25, 2019: Angewandte Chemie
Mingchun Gao, Minfen Zou, Jue Wang, Qitao Tan, Bingxin Liu, Bin Xu
A palladium-catalyzed multicomponent reaction of alkynes, carboxylic acids, and isocyanides has been developed with the assistance of silver salt under mild conditions. Highly functionalized captodative olefins are synthesized efficiently by this method, which can find many applications as versatile synthons in organic synthesis.
February 25, 2019: Organic Letters
Pengli Bao, Leilei Wang, Huilan Yue, Yun Shao, Jiangwei Wen, Daoshan Yang, Xiaohui Zhao, Hua Wang, Wei Wei
A novel molecular iodine-catalyzed protocol for the construction of thiocarbamates from readily available sodium sulfinates, isocyanides, and water has been described. The present methodology offers a facile and practical route to a variety of thiocarbamates in moderate to good yields with favorable functional group tolerance by use odorless sodium sulfinates as the sulfur source. The mechanistic studies suggest the present transformation involves a radical process.
February 18, 2019: Journal of Organic Chemistry
Wenyan Hao, Yuchen Sha, Yi Deng, Yi Luo, Li Zeng, Shan Tang, Yue Weng, Chien-Wei Chiang, Aiwen Lei
An in-situ generated oxidation species of nickel quino-linylpropioamide intermediate was produced. Characterization by XANES and EPR provides complementary insights into this oxidized nickel species. With aliphatic amides and isocyanides as substrates, a nickel-catalyzed facile synthesis of structurally diverse five-membered lactams could be achieved.
February 15, 2019: Chemistry: a European Journal
Xiaofang Lei, Yuanyuan Wang, Erkang Fan, Zhihua Sun
Activation of disulfides with N-halogen succinimide in the presence of TEMPO allows insertion reaction by an isocyanide, the product of which can further accept a wide range of nucleophiles for the generation of isothioureas and related molecular moieties. This new procedure overcomes previous methods that accept essentially only aryl amines as the third nucleophilic component. The diverse nucleophiles usable in our new protocol make this approach a general method for de novo synthesis of many S-containing heterocycles...
February 11, 2019: Organic Letters
John E Ellis
Joseph Chatt was the first to discover in the early 1960s that previously unknown transition metal compounds were accessible and isolable via the reactions of alkali metal arene radical anions with transition metal precursors containing good leaving groups, such as weakly basic neutral or anionic ligands, especially halides. Later Peter Timms confirmed the importance of these early studies with the synthesis of several new bis(arene)metal(0) sandwich compounds by a variant of Chatt's route. Following a brief historical survey of alkali metal arene compounds, first examined in some detail by Wilhelm Schlenk, use of these reagents in the conventional syntheses of anionic homoleptic arene metal complexes of the d-block elements will be described...
February 6, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
William W Brennessel, Alexander Romanenkov, Victor G Young, John E Ellis
Treatment of tetraethylammonium hexacarbonyltantalate, [Et4 N][Ta(CO)6 ], with 1.1 equivalents of molecular iodine (I2 ) in tetrahydrofuran (THF) at 200 K, followed by the addition of 6.0 equivalents of 2,6-diisopropylphenyl isocyanide (CNDipp) and slow warming to 293 K over a 24 h period gave the tantalum(I) iodide derivative hexakis(2,6-diisopropylphenyl isocyanide-κC)iodidotantalum(I), [TaI(C13 H17 N)6 ] or TaI(CNDipp)6 , 1. Recrystallization of this substance from pentane provided deep-red nearly black parallelepipeds of the product, which was characterized by single-crystal X-ray diffraction...
February 1, 2019: Acta Crystallographica. Section C, Structural Chemistry
Shabnam Shaabani, Ruixue Xu, Maryam Ahmadianmoghaddam, Li Gao, Martin Stahorsky, Joe Olechno, Richard Ellson, Michael Kossenjans, Victoria Helan, Alexander Dömling
Automated, miniaturized and accelerated synthesis for efficient property optimization is a formidable challenge for chemistry in the 21st century as it helps to reduce resources and waste and can deliver products in shorter time frames. Here, we used for the first-time acoustic droplet ejection (ADE) technology and fast quality control to screen efficiency of synthetic reactions on a nanomole scale in an automated and miniaturized fashion. The interrupted Fischer indole combined with Ugi-type reactions yielded several attractive drug-like scaffolds...
January 21, 2019: Green Chemistry: An International Journal and Green Chemistry Resource: GC
Ze-Fan Zhu, Miao-Miao Zhang, Feng Liu
An efficient and mild method was developed for the synthesis of 6-alkylated phenanthridines upon visible light irradiation. Bench-stable and easily handled redox-active Katritzky pyridinium salts derived from abundant amino acids/peptides were used as radical precursors for the alkylation of isocyanobiphenyl species. The reaction displays an excellent functional group tolerance and a potential utility for peptide functionalization, allowing access to desired products in good to excellent yields.
January 25, 2019: Organic & Biomolecular Chemistry
Na Liu, Fei Chao, Ming-Guo Liu, Nian-Yu Huang, Kun Zou, Long Wang
This paper reports the tandem-reaction strategy of Passerini/Staudinger/aza-Wittig reaction based on the in-situ capture of isocyanides. According to this strategy, isocyanides are synthesized in situ, which immediately work as the substrate for Passerini reaction and post-modified tandem reaction in one-pot. In addition, two types new compounds of 5-oxo-3,5-dihydrobenzo[e][1,4] oxazepines and 6-oxo-5,6-dihydro-2H-1,4-oxazines were synthesized using the tandem-reaction strategy which undergos five-step transformations in one-pot...
January 24, 2019: Journal of Organic Chemistry
Ana Bornadiego, Jesús Díaz, Carlos F Marcos
Aminoxanthones constitute a group of therapeutically promising compounds that so far have been synthetically challenging. Here, we report the synthesis of both aminodihydroxanthones and fully aromatized aminoxanthones by an easy to perform, one-step multicomponent reaction of isocyanides, 3-carbonylchromones and dienophiles. The mechanism of the reaction involves a sequence of a [4 + 1] cycloaddition, iminolactone-aminofuran tautomerization, [4 + 2] cycloaddition, oxygen ring opening and aromatization. Remarkably, DFT quantum chemical computations revealed that the iminolactone-aminofuran tautomerization requires the assistance of a water molecule and, contrary to intuition, it is the rate-determining step...
January 22, 2019: Organic & Biomolecular Chemistry
Bérenger Gans, Gustavo A Garcia, Séverine Boyé-Péronne, Stephen T Pratt, Jean-Claude Guillemin, Alfredo Aguado, Octavio Roncero, Jean-Christophe Loison
The photoelectron spectrum of the X1Σ+ → X+2Σ+ ionizing transition of hydrogen isocyanide (HNC) is measured for the first time at a fixed photon energy (13 eV). The assignment of the spectrum is supported by wave-packet calculations simulating the photoionization transition spectrum and using ab initio calculations of the potential energy surfaces for the three lowest electronic states of the cation. The photoelectron spectrum allows the retrieval of the fundamental of the CN stretching mode of the cationic ground state ([small nu, Greek, tilde]3 = 2260 ± 80 cm-1) and the adiabatic ionization energy of hydrogen isocyanide: IE(HNC) = 12...
January 18, 2019: Physical Chemistry Chemical Physics: PCCP
Patrizio Orecchia, Weiming Yuan, Martin Oestreich
A straightforward gram-scale preparation of cyclohexa-1,4-diene-based hydrogen cyanide (HCN) surrogates is reported. These are bench-stable but formally release HCN and rearomatize when treated with Lewis acids. For BCl3, the formation the isocyanide adduct [(CN)BCl3]- and the corresponding Wheland complex was verified by mass spectrometry. In the presence of 1,1-di- and trisubstituted alkenes, transfer of HCN from the surrogate onto the C-C double bond occurs, affording highly substituted nitriles with Markovnikov selectivity...
January 9, 2019: Angewandte Chemie
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