55337-53-6Relevant academic research and scientific papers
Br?nsted acidic cellulose-PO3H: An efficient catalyst for the chemoselective synthesis of fructones and trans-esterification via condensation of acetoacetic esters with alcohols and diols
Naikwadi, Dhanaji R.,Singh, Amravati S.,Biradar, Ankush V.
, (2021/10/04)
Cellulose is the most abundant organic source and has expedient a great deal of interest as renewable and emerged as sustainable feedstock. The functionalization of cellulose as designed catalytic system intriguing furnished to the production of fine chemicals. Herein, we synthesized an environmental friendly solid acid catalyst by functionalizing cellulose with phosphoric acid (PO3H). The successful functionalization of cellulose with PO3H was confirmed by 31P NMR, ICP-OES, FE-SEM, and XPS analysis. ICP-OES revealed the presence of phosphorus content of ～1.0 wt. % on the catalyst's surface while elemental mapping by FESEM and XPS shows a uniform distribution of phosphorus over the material. The synthesized solid acid catalyst was utilized for condensation of diols with acetoacetic esters in solvent-free conditions to synthesize fine chemicals. The present approach not only circumvented the one-step protection and other products but more fascinatingly provided trans-esterification of acetoacetic esters with diols and n-alcohols. The catalyst was successfully used for chemoselective protection on ethyl acetoacetate with 1, 2 diols to essential fructone molecule with ～100% conversion and 99% selectivity. The results suggested that the catalyst has the advantage over commercial solid acid heterogeneous and homogeneous catalysts.
One-Pot Synthesis of 2-Acetyl-1 H-pyrroles from N-Propargylic β-Enaminones via Intermediacy of 1,4-Oxazepines
Kanova, Nilay,Dundar, Buse Aysen,Kelgokmen, Yilmaz,Zora, Metin
, p. 6289 - 6304 (2021/05/06)
A one-pot two-step protocol for the synthesis of 2-acetyl-1H-pyrroles from N-propargylic β-enaminones was described. When treated with zinc chloride in refluxing chloroform, N-propargylic β-enaminones produced in situ 2-methylene-2,3-dihydro-1,4-oxazepines, which, upon further refluxing in methanol with zinc chloride, afforded 2-acetyl-1H-pyrroles. The process was found to be general for a wide variety of N-propargylic β-enaminones and yielded a diverse range of 2-acetyl-1H-pyrroles in good to high yields with large substrate scope and good functional group tolerance. This operationally easy method may provide a rapid access to functionalized 2-acetyl-1H-pyrroles of pharmacological interest.
Palladium on Carbon-Catalyzed Benzylic Methoxylation for Synthesis of Mixed Acetals and Orthoesters
Yasukawa, Naoki,Kanie, Takafumi,Kuwata, Marina,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
, p. 10974 - 10977 (2017/08/22)
The palladium on carbon (Pd/C)-catalyzed direct methoxylation of the benzylic positions of linear benzyl and cyclic ether substrates proceeded in the presence of i-Pr2NEt under an oxygen atmosphere to give the corresponding mixed acetals. Cyclic acetal derivatives could also be converted into orthoesters. The present direct methoxylation via a carbon-hydrogen (C?H) functionalization can be accomplished using the easily-removed Pd/C and molecular oxygen as a green oxidant. The obtained mixed acetals were transformed into the corresponding ether products by chemoselective substitution of the methoxy group using a silyltriflate, 2,4,6-collidine, and a nucleophile. The orthoester derivative could also be transformed into the cyclic ketal under similar reaction conditions.
Acylketene acetals in organic synthesis
Eid Jr.,Konopelski
, p. 975 - 992 (2007/10/02)
The preparation and reactivity of achiral and enantiomerically pure acylketene acetals are described. The key reactions of these substrates involve facile conjugate hydroboration and organolithium addition. Enantiomerically pure acylketene acetals were employed to generate a homochiral β-keto ketal through a highly diastereoselective lithium enolate quench. This β-ketal, which was also prepared through a desymmetrization ketalization reaction on a meso dione, was employed in the synthesis of the insect pheromone sitophilure.
Conjugate hydroboration-reduction and organolithium additions to acylketene acetals. Synthesis of monoprotected β-dicarbonyls
Eid Jr.,Konopelski
, p. 305 - 306 (2007/10/02)
Hydride and organolithium additions to acylketene acetals are presented. Results indicate conjugate addition to be the dominant reaction pathway, resulting in the formation of monoprotected β-diketones and β-ketoaldehydes.
