17217-84-4Relevant academic research and scientific papers
Experimental and Theoretical Studies on Gas-Phase Fragmentation Reactions of Protonated Methyl Benzoate: Concomitant Neutral Eliminations of Benzene, Carbon Dioxide, and Methanol
Xia, Hanxue,Zhang, Yong,Attygalle, Athula B.
, p. 1601 - 1610 (2018)
Protonated methyl benzoate, upon activation, fragments by three distinct pathways. The m/z 137 ion for the protonated species generated by helium-plasma ionization (HePI) was mass-selected and subjected to collisional activation. In one fragmentation path
Zinc bromide promoted coupling of isonitriles with carboxylic acids to form 2,4,5-trisubstituted oxazoles
Odabachian, Yann,Tong, Shuo,Wang, Qian,Wang, Mei-Xiang,Zhu, Jieping
, p. 10878 - 10882 (2013)
Deviant behavior: In a deviation from "normal" reactivity, isocyanides underwent co-trimerization with carboxylic acids in the presence of ZnBr2 to smoothly provide oxazoles (see scheme). The reaction is thought to occur by initial nucleophilic
Phosphorus-Based Organocatalysis for the Dehydrative Cyclization of N-(2-Hydroxyethyl)amides into 2-Oxazolines
Soleymani Movahed, Farzaneh,Foo, Siong Wan,Mori, Shogo,Ogawa, Saeko,Saito, Susumu
supporting information, p. 243 - 257 (2021/12/17)
A metal-free, biomimetic catalytic protocol for the cyclization of N-(2-hydroxyethyl)amides to the corresponding 2-oxazolines (4,5-dihydrooxazoles), promoted by the 1,3,5,2,4,6-triazatriphosphorine (TAP)-derived organocatalyst tris(o-phenylenedioxy)cyclotriphosphazene (TAP-1) has been developed. This approach requires less precatalyst compared to the reported relevant systems, with respect to the phosphorus atom (the maximum turnover number (TON) ～30), and exhibits a broader substrate scope and higher functional-group tolerance, providing the functionalized 2-oxazolines with retention of the configuration at the C(4) stereogenic center of the 2-oxazolines. Widely accessible β-amino alcohols can be used in this approach, and the cyclization of N-(2-hydroxyethyl)amides provides the desired 2-oxazolines in up to 99% yield. The mechanism of the reaction was studied by monitoring the reaction using spectral and analytical methods, whereby an 18O-labeling experiment furnished valuable insights. The initial step involves a stoichiometric reaction between the substrate and TAP-1, which leads to the in situ generation of the catalyst, a catechol cyclic phosphate, as well as to a pyrocatechol phosphate and two possible active intermediates. The dehydrative cyclization was also successfully conducted on the gram scale.
18O-Labeled chiral compounds enable the facile determination of enantioselectivity by mass spectroscopy
Mandai, Kyoko,Tsuchihashi, Yuta,Ashikari, Yosuke,Yoshida, Jun-ichi,Nagaki, Aiichiro
supporting information, (2019/12/24)
The synthesis of 18O-labeled enantioenriched compounds and their facile evaluation system to determine enantiomeric excess (ee) using mass spectroscopy was described. Equimolar mixture of 18O-labeled and non-labeled pseudo-enantiomers were used as a substrate for enzyme-catalyzed kinetic resolution. Ees determined by mass spectroscopy showed good agreement with those by HPLC. Our method would be a promising tool for fast evaluation of ee and contribute to development of enantioselective transformations.
Selective C-C bond cleavage of amides fused to 8-aminoquinoline controlled by a catalyst and an oxidant
Li, Sen,Jie, Kun,Yan, Wenjie,Pan, Qingjun,Zhang, Min,Wang, Yufeng,Fu, Zhengjiang,Guo, Shengmei,Cai, Hu
supporting information, p. 13820 - 13823 (2020/11/18)
Herein, copper-catalyzed direct C-C bond cleavage of amides fused to 8-aminoquinoline as a directing group to form urea in the presence of amines and dioxygen is reported. Compared to the previous C-H aminations of amides via C-H activation, this reaction presents a catalyst and oxidant controlled C-C bond cleavage strategy that enables amidation through a radical process. CuBr/Ag2CO3/O2 shows the best catalytic result at 150 °C. A series of aryl and alkyl amides were compatible with this transformation. Notably, this method provided access to cyclohexanone, one of the most important industrial materials. The pathway of this reaction was investigated.
Transformations of N-arylpropiolamides to indoline-2,3-diones and acids via C≡C triple bond oxidative cleavage and C(sp2)–H functionalization
Zhou, Ming-Bo,Li, Yang,Ouyang, Xuan-Hui,Li, Jin-Heng
, p. 222 - 227 (2019/11/13)
A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described, which is promoted by a cooperative action of catalytic CuBr2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and O2. The method provides a practical tool for transformations of alkynes by means of a C–H functionalization strategy, which enables the formation of one C–C bond and multiple C–O bonds in a single reaction with high substrates compatibility and excellent functional group tolerance.
Copper-catalyzed oxidative cleavage of Passerini and Ugi adducts in basic medium yielding α-ketoamides
Ghoshal, Anirban,Ambule, Mayur D.,Sravanthi, Revoju,Taneja, Mohit,Srivastava, Ajay Kumar
supporting information, p. 14459 - 14474 (2019/10/01)
The aerobic oxidative cleavage of Passerini and Ugi adducts in the presence of base and copper(i) iodide is studied in detail. The oxidative cleavage yields α-ketoamides along with acids and amides from Passerini and Ugi adducts respectively. Mechanistic investigations revealed that the reaction proceeds via a radical pathway involving molecular oxygen. Control experiments with 18O-labeled Passerini adducts confirmed that molecular oxygen is the source of oxygen in α-ketoamides. A variety of Passerini and Ugi adducts were studied to explore the effect of substitution. Overall, the present study provides an insight into the reactivity of Passerini and Ugi adducts in strong basic conditions along with a method to prepare α-ketoamides.
Rhodium-Catalyzed Formal C-O Insertion in Carbene/Alkyne Metathesis Reactions: Synthesis of 3-Substituted 3 H-Indol-3-ols
Jia, Shikun,Dong, Guizhi,Ao, Chaoqun,Jiang, Xianxing,Hu, Wenhao
supporting information, p. 4322 - 4326 (2019/06/17)
An efficient and novel rhodium-catalyzed formal C-O insertion reaction of alkyne-tethered diazo compounds for the synthesis of 3H-indol-3-ols is described. A type of donor/donor rhodium carbene generated in situ via a carbene/alkyne metathesis (CAM) proce
Nitrogen Dioxide Catalyzed Aerobic Oxidative Cleavage of C(OH)–C Bonds of Secondary Alcohols to Produce Acids
Liu, Mingyang,Zhang, Zhanrong,Song, Jinliang,Liu, Shuaishuai,Liu, Huizhen,Han, Buxing
supporting information, p. 17393 - 17398 (2019/11/11)
Stable organic nitroxyl radicals are an important class of catalysts for oxidation reactions, but their wide applications are hindered by their steric hinderance, high cost, complex operation, and separation procedures. Herein, NO2 in DMSO is shown to effectively catalyze the aerobic oxidative cleavage of C(OH)?C bonds to form a carboxylic group, and NO2 was generated in situ by decomposition of nitrates. A diverse range of secondary alcohols were selectively converted into acids in excellent yields in this transition-metal-free system without any additives. Preliminary results also indicate its applicability to depolymerize recalcitrant macromolecular lignin. Detail studies revealed that NO2 from nitrates promoted the reaction, and NO2 served as hydrogen acceptor and radical initiator for the tandem oxidative reaction.
A Three-Component Enantioselective Cyclization Reaction Catalyzed by an Unnatural Amino Acid Derivative
de Gracia Retamosa, María,Ruiz-Olalla, Andrea,Bello, Tamara,de Cózar, Abel,Cossío, Fernando P.
supporting information, p. 668 - 672 (2018/01/17)
A new diastereo- and enantioselective three-component cyclization reaction is described. The reaction takes place between a ketone, a carboxylic acid, and a nitroalkene to yield a bicyclic octahydro-2H-indol-2-one scaffold possessing three chiral centers. This reaction involves a rearrangement of the nitro group under simple thermal conditions. A plausible mechanism is proposed for this new reaction based on DFT calculations and isotope-labeling experiments. A new concise enantioselective synthesis of the alkaloid (+)-pancracine is presented as an example of the potential of this novel organocatalytic cyclization reaction in the synthesis of natural products.
