1487-57-6Relevant academic research and scientific papers
Esterification of levulinic acid over Sn(II) exchanged Keggin heteropolyacid salts: An efficient route to obtain bioaditives
Da Silva, Márcio José,Chaves, Diego Morais,Teixeira, Milena Galdino,Oliveira Bruziquesi, Carlos Giovani
, (2021)
In this paper, we describe a process to add value to the biomass derivatives (i.e., levulinic acid), converting it to bioadditives over solid Sn(II) exchanged Keggin heteropolyacid salts. These solid catalysts are an attractive alternative to the traditional soluble and corrosive Br?nsted acid catalysts. Among Sn(II) heteropoly salts, the Sn1.5PW12O40 was the most active and selective catalyst, achieving high conversions (ca. 90 %) and selectivity (90–97 %) for alkyl esters and angelica lactone, the main reaction products. The impacts of the main reaction parameters (i.e., catalyst load, temperature, and the molar ratio of alcohol to acid) were investigated. The use of renewable raw material, and an efficient and recyclable catalyst are the main positive features of this process. The Sn1.5PW12O40 catalyst was easily recovered and reused without loss activity.
Dibromo-BODIPY as an Organic Photocatalyst for Radical-Ionic Sequences
Garciá-Santos, William H.,Ordó?ez-Hernández, Javier,Farfán-Paredes, Mónica,Castro-Cruz, Hiram M.,Maciás-Ruvalcaba, Norma A.,Farfán, Norberto,Cordero-Vargas, Alejandro
, p. 16315 - 16326 (2021/11/18)
A new dibrominated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) is reported as a new metal-free photocatalyst. This BODIPY showed similar optoelectronic, electrochemical, and performance properties to those of Ru(bpy)3Cl2, one of the most common photocatalysts in a known radical-ionic transformation, such as the formation of 1,4-dicarbonyl compounds. Moreover, additional sequences in which the generated oxonium ion is trapped by an internal nucleophile were developed using this BODIPY photocatalyst. These new sequences allowed the straightforward preparation of ?3-alkoxylactones, monoprotected 1,4-ketoaldehydes, and dihydrofurans. This new catalyst, the methodology, and the forged functional groups could be important tools in organic synthesis.
Cyclisation of Alkynecarboxylic Acids: a Route to an Oxaspirolactone
Yamamoto, Makoto,Yoshitake, Makoto,Yamada, Kazutoshi
, p. 991 - 992 (2007/10/02)
Pent-4-ynoic acid, in various alcohols, was cyclised in the presence of yellow mercury(II) oxide to 4,5-dihydro-5-alkoxy-5-methylfuran-2(3H)-ones; 8-hydroxyoct-4-ynoic acid was also cyclised in dimethylformamide to 1,6-dioxaspirodecan-2-one in good y
