114691-91-7Relevant academic research and scientific papers
High-Fidelity End-Functionalization of Poly(ethylene glycol) Using Stable and Potent Carbamate Linkages
Cen, Jie,Hu, Jinming,Li, Lei,Liu, Guhuan,Liu, Shiyong,Shi, Shengyu,Yao, Chenzhi
supporting information, p. 18172 - 18178 (2020/08/21)
Commercial PEG-amine is of unreliable quality, and conventional PEG functionalization relies on esterification and etherification steps, suffering from incomplete conversion, harsh reaction conditions, and functional-group incompatibility. To solve these challenges, we propose an efficient strategy for PEG functionalization with carbamate linkages. By fine-tuning terminal amine basicity, stable and high-fidelity PEG-amine with carbamate linkage was obtained, as seen from the clean MALDI-TOF MS pattern. The carbamate strategy was further applied to the synthesis of high-fidelity multi-functionalized PEG with varying reactive groups. Compared to with an ester linkage, amphiphilic PEG-PS block copolymers bearing carbamate junction linkage exhibits preferential self-assembly tendency into vesicles. Moreover, nanoparticles of the latter demonstrate higher drug loading efficiency, encapsulation stability against enzymatic hydrolysis, and improved in vivo retention at the tumor region.
Direct conversion of carboxylic acids to various nitrogen-containing compounds in the one-pot exploiting curtius rearrangement
Kumar, Arun,Kumar, Naveen,Sharma, Ritika,Bhargava, Gaurav,Mahajan, Dinesh
, p. 11323 - 11334 (2019/09/10)
Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.
The challenge of palladium-catalyzed aromatic azidocarbonylation: From mechanistic and catalyst deactivation studies to a highly efficient process
Miloserdov, Fedor M.,McMullin, Claire L.,Belmonte, Marta Martinez,Benet-Buchholz, Jordi,Bakhmutov, Vladimir I.,Macgregor, Stuart A.,Grushin, Vladimir V.
supporting information, p. 736 - 752 (2014/03/21)
Azidocarbonylation of iodoarenes with CO and NaN3, a novel Heck-type carbonylation reaction, readily occurs in an organic solvent-H 2O biphasic system to furnish aroyl azides at room temperature and 1 atm. The reaction is catalyzed by Xantphos-Pd and exhibits high functional group tolerance. The catalyst deactivation product, [(Xantphos)PdI2], can be reduced in situ with PMHS to Pd(0) to regain catalytic activity. In this way, the catalyst loading has been lowered to 0.2% without any losses in selectivity at nearly 100% conversion to synthesize a series of aroyl azides in 80-90% isolated yield on a gram scale. Alternatively, the ArCON3 product can be used without isolation for further transformations in situ, e.g., to isocyanates, ureas, benzamides, and iminophosphoranes. A detailed experimental and computational study has identified two main reaction pathways for the reaction. For both routes, Ar-I oxidative addition to Pd(0) is the rate-determining step. In the presence of CO in excess, the Ar-I bond is activated by the less electron-rich Pd center of a mixed carbonyl phosphine complex. Under CO-deficient conditions, a slightly lower energy barrier pathway is followed that involves Ar-I oxidative addition to a more reactive carbonyl-free (Xantphos)Pd0 species. Mass transfer in the triphasic liquid-liquid-gas system employed for the reaction plays an important role in the competition between these two reaction channels, uniformly leading to a common aroyl azido intermediate that undergoes exceedingly facile ArCO-N 3 reductive elimination. Safety aspects of the method have been investigated.
Palladium-catalyzed aromatic azidocarbonylation
Miloserdov, Fedor M.,Grushin, Vladimir V.
supporting information; experimental part, p. 3668 - 3672 (2012/05/20)
Aryl iodides smoothly react with NaN3 and CO in the presence of a Pd/Xantphos catalyst to give aroyl azides (ArCON3) in 75-92 % yield. The reaction occurs under mild reaction conditions (1 atm, 20-50 °C) and exhibits high functional-group tolerance. (Xantphos=9,9-dimethyl-4,5- bis(diphenylphosphino)xanthene)
Direct synthesis of acyl azides from carboxylic acids by the combination of trichloroacetonitrile, triphenylphosphine and sodium azide
Kim, Joong-Gon,Jang, Doo Ok
experimental part, p. 2072 - 2074 (2009/04/07)
Various carboxylic acids were converted into acyl azides in excellent yields by treating with trichloroacetonitrile, triphenylphosphine and sodium azide at room temperature. The reaction was applicable to the preparation of dipeptide without rearrangement.
AROYLNITRENES WITH SINGLET GROUND STATES: PHOTOCHEMISTRY OF ACETYL-SUBSTITUTED AROYL AND ARYLOXYCARBONYL AZIDES
Sigman, Michael E.,Autrey, Tom,Schuster, Gary B.
, p. 4297 - 4305 (2007/10/02)
The photochemistry of 4-acetylbenzoyl azide (ABA), 4-acetyl-4'-biphenoyl azide (ADA), and 4-acetylphenoxycarbonyl azide (APA) shows unusual wavelength and structrural effects.Irradiation of ABA or ADA into their ?-?* bands with deep-UV light leads to formation of 4-acetylbenzoylnitrene (ABN) and 4-acetyl-4'-biphenylnitrene (ADN), respectively, in competition with photo-Curtis rearrangement to form isocyanates.Irradiation of these azides into their n-?* bands with near-UV light gives only the aroylnitrenes.The triplet excited states of the azides were detected chemically and by transient spectroscopic techniques.Nitrogen loss following near-UV irradiation occurs exclusively from the excited triplet azides.However, the chemical properties of ABN and ADN are consistent only with reactions originating from their singlet states.An ESR spectrum is observed at 8 K for ((4-acetylphenoxy)carbonyl)nitrene (APN) but not for 4-acetylbenzoylnitrene (ABN) of 4-acetyl-4'-biphenylcarbonylnitrene (ADN).The chemical properties of APN in tert-butyl alcohol show that its triplet is no more than 5 kcal/mol below its lowest single state.In contrast, the chemical properties of ABN and ADN indicate that these niterenes have singlet ground states.
