4195-19-1Relevant articles and documents
Combined Photoredox and Carbene Catalysis for the Synthesis of γ-Aryloxy Ketones
Wang, Pengzhi,Fitzpatrick, Keegan P.,Scheidt, Karl A.
supporting information, p. 518 - 524 (2021/12/16)
N-heterocyclic carbenes (NHCs) have emerged as catalysts for the construction of C?C bonds in the synthesis of substituted ketones under single-electron processes. Despite these recent reports, there still remains a need to increase the utility and practicality of these reactions by exploring new radical coupling partners. Herein, we report the synthesis of γ-aryloxyketones via combined NHC/photoredox catalysis. In this reaction, an α-aryloxymethyl radical is generated via oxidation of an aryloxymethyl potassium trifluoroborate salt, which is then added into styrene derivatives to provide a stabilized benzylic radical. Subsequent radical-radical coupling reaction with an azolium radical affords the γ-aryloxy ketone products. (Figure presented.).
Chemoselective acylation of 2-amino-8-quinolinol in the generation of C2-amides or C8-esters
Park, Yongseok,Fei, Xiang,Yuan, Yue,Lee, Sanha,Hur, Joonseong,Park, Sung Jean,Jung, Jae-Kyung,Seo, Seung-Yong
, p. 41955 - 41961 (2017/09/12)
Two different ways to carry out the chemoselective acylation of 2-amino-8-quinolinol with unique features to generate C2-amides or C8-esters were developed. The coupling reaction with a variety of carboxylic acids using EDCI and DMAP provided C8-ester derivatives, whereas N-heteroaromatic acids were not introduced on the C8-hydroxy group, but rather on the C2-amino group under the same conditions. To obtain C2-amides selectively, the anionic nucleophile from 2-amino-8-quinolinol was treated with less reactive acyl imidazolides or esters.
Stability studies of N-acylimidazoles
Zaramella, Simone,Stroemberg, Roger,Yeheskiely, Esther
, p. 2633 - 2639 (2007/10/03)
Studies of the stabilities of a series of N-acylimidazoles towards acidic and basic conditions of potential usefulness for the removal of common temporary protection in peptide and oligonucleotide synthesis are presented. N-Acylimidazoles with a variety of substituents in the acyl component were prepared and treated with 3% trifluoroacetic acid (TFA) in chloroform and with 2% 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in N,N-dimethylformamide (DMF), the extent of their degradation being determined by proton NMR. N-(2,4,6-Trimethylbenzoyl)imidazole (1) and N-(2,6-dimethoxybenzoyl)-imidazole (2) remained unaffected under the above acidic and basic conditions after 4 d and 2 d, respectively. In addition, 1 and 2 were resistant to treatment with a solution of 2% piperidine/2% DBU in DMF for 24 h. Under ammonolytic conditions, 2 was rapidly cleaved (less than 1 h), whereas 1 was 64% degraded after 48 h, as ascertained by reversed-phase HPLC. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
