2065-27-2Relevant academic research and scientific papers
Robust synthesis of NIR-emissive P-rhodamine fluorophores
Arndt, Hans-Dieter,Nasufovic, Veselin,Sauer, Maria,Vilotijevic, Ivan
supporting information, p. 1567 - 1571 (2020/03/06)
P-Rhodamines were accessed by implementing a robust three step sequence consisting of (i) addition of m-metallated anilines to dichlorophosphine oxides, (ii) selective dibromination, and (iii) cyclization of the diaryllithium reagents derived from the dib
Phosphorylation Organocatalysts Highly Active by Design
Dobrovetsky, Roman,Fallek, Amit,Kramer, Maria,Portnoy, Moshe,Weiss-Shtofman, Mor
supporting information, (2020/05/01)
The activity of nucleophilic organocatalysts for alcohol/phenol phosphorylation was enhanced through attaching oligoether appendages to a benzyl substituent on imidazole- or aminopyridine-based active units, presumably because of stabilizing n-cation interactions of the ethereal oxygens with the positively charged aza-heterocycle in the catalytic intermediates, and was substantially higher than that of known benchmark catalysts for a range of substrates. Density functional theory calculations and the study of analogues having a lower potential for such stabilizing interactions support our hypothesis.
Electrochemical C-H cyanation of electron-rich (Hetero)arenes
Hayrapetyan, Davit,Rit, Raja K.,Kratz, Markus,Tschulik, Kristina,Goo?en, Lukas J.
supporting information, p. 11288 - 11291 (2018/10/20)
A straightforward method for the electrochemical C-H cyanation of arenes and heteroarenes that proceeds at room temperature in MeOH, with NaCN as the reagent in a simple, open, undivided electrochemical cell is reported. The platinum electrodes are passivated by ad-sorbed cyanide, which allows conversion of an exceptionally broad range of electron-rich substrates all the way down to dialkyl arenes. The cyanide electrolyte can be replenished with HCN, opening opportunities for salt-free industrial C-H cyanation.
An electrochemical method for carboxylic ester synthesis from N-alkoxyamides
Subramanian, Kripa,Yedage, Subhash L.,Bhanage, Bhalchandra M.
, p. 10025 - 10032 (2018/05/31)
An electrochemical method for the synthesis of carboxylic as well as hindered esters from N-alkoxyamides has been reported. The electrochemical reaction proceeds through constant current electrolysis (CCE) by taking advantage of the dual role of n-Bu4NI (TBAI) as the redox catalyst as well as the supporting electrolyte. Besides providing mild reaction conditions, the present protocol is free from external oxidants and conducting salts, thereby generating nitrogen as the nonhazardous side product. Additionally, the developed procedure is highly advantageous due to its short reaction time, wide substrate scope, and gram-scale synthesis.
Nitrogen enriched mesoporous organic polymer anchored copper(ii) material: An efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems
Molla, Rostam Ali,Iqubal, Md. Asif,Ghosh, Kajari,Kamaluddin,Islam, Sk. Manirul
, p. 6546 - 6559 (2015/04/14)
A new copper-grafted mesoporous poly-melamine-formaldehyde (Cu-mPMF) has been synthesized from melamine and paraformaldehyde in DMSO medium, followed by grafting of Cu(ii) at its surface. Cu-mPMF has been characterized by elemental analysis, powder XRD, HR TEM, FE-SEM, N2 adsorption study, FT-IR, UV-vis DRS, TGA-DTA, EPR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The Cu-grafted mesoporous material showed very good catalytic activity in methyl esterification of benzylic alcohols and amidation of nitriles. Moreover, the catalyst is easily recoverable and can be reused seven times without appreciable loss of catalytic activity in the above reactions. The highly dispersed and strongly bound Cu(ii) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-mPMF catalyst. Due to strong binding with the functional groups of the polymer, no evidence of leached copper from the catalyst during the course of reaction emerged, suggesting true heterogeneity in the catalytic process. This journal is
Copper-catalyzed methyl esterification reactions via C-C bond cleavage
Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
, p. 9898 - 9905 (2013/10/22)
The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
Facile preparation of aromatic esters from aromatic bromides with ethyl formate or DMF and molecular iodine via aryllithium
Ushijima, Sousuke,Moriyama, Katsuhiko,Togo, Hideo
experimental part, p. 4701 - 4709 (2012/07/28)
Various aromatic bromides were treated with n-BuLi and subsequently with ethyl formate, followed by the reaction with ethanol and molecular iodine in the presence of K2CO3 to provide the corresponding aromatic ethyl esters in good yields. Moreover, aromatic bromides could be transformed into the corresponding aromatic methyl esters in good yields by the treatment with n-BuLi and subsequently with DMF, followed by the reaction with methanol, molecular iodine, and K2CO3. Some aromatics could be also converted into the corresponding aromatic esters in good yields by the treatment with n-BuLi, and subsequently with ethyl formate or DMF, followed by the reaction with molecular iodine and K2CO3. The present reactions offer a novel route for the transition-metal-free, carbon-monoxide-free, and therefore environmentally benign one-pot conversion of aromatic bromides and aromatics into aromatic esters.
A simple and efficient total synthesis of (±)-danshexinkun A, a bioactive diterpenoid from Salvia miltiorrhiza
Moghaddam, Firouz Matloubi,Farimani, Mahdi Moridi
supporting information; experimental part, p. 540 - 542 (2010/10/02)
An efficient 12-step route for the synthesis of the diterpenoid quinone (±)-danshexinkun A in 23% overall yield from the corresponding highly substituted stilbene using a photocyclization strategy is described.
The first general and selective palladium(II)-catalyzed alkoxycarbonylation of arylboronates: Interplay among benzoquinone-ligated palladium(0) complex, organoboron, and alcohol solvent
Yamamoto, Yoshihiko
scheme or table, p. 478 - 492 (2010/07/03)
Methoxycarbonylation of aryl- and alken-ylboron compounds was performed using the palladium (II) acetate/triphenylphosphine [PdACHTUNGTRENNUNG(OAc) 2/PPh3] catalyst with p-benzoquinone as a stoichiometric oxidant in methanol at ambient temperature to obtain the corresponding methyl esters in good yields. A wide variety of functional groups including various carbonyl functionalities, nitrile, nitro, sulfone, and unprotected pyrrole rings were tolerated in the methoxycarbonlation, while the use of higher alcohols except for tert-butanol afforded various pchlorobenzoates in moderate to high yields. The catalytic alkoxycarbonylation proceeded without any acid or base additive, and an oxidative transmetalation step is proposed to explain the exceptional efficacy of this protocol. DFT and MP2 calculations support the proposed mechanism.
Organocatalyst-mediated enantioselective intramolecular aldol reaction featuring the rare combination of aldehyde as nucleophile and ketone as electrophile
Hayashi, Yujiro,Sekizawa, Hiromi,Yamaguchi, Junichiro,Gotoh, Hiroaki
, p. 6493 - 6499 (2008/02/10)
(Chemical Equation Presented) The trifluoroacetic acid salt of 2-(pyrrolidinylmethyl)pyrrolidine was found to be an effective organocatalyst of an asymmetric intramolecular aldol reaction, affording bicyclo[4.3.0]nonane derivatives with a high enantiosele
