25172-51-4Relevant academic research and scientific papers
Acid Catalyzed Direct-Amidation-Dehydrocyclization of 2-Hydroxy-acetophenones to Benzoxazoles by a One-Pot Sustainable Synthesis
Rancan, Elia,Aric, Fabio,Quartarone, Giuseppe,Ronchin, Lucio,Vavasori, Andrea
, p. 939 - 946 (2015/08/06)
A series of 2-methyl-benzoxazoles have been synthesized starting from 2-hydroxy-acetophenones via a one-pot three steps reaction. Hydroxylamonium salt has been used as amidation agent. The reaction occurs with different anions, but the best results is achieved with hydroxylamonium hydrchloride. Despite the number of consecutive stages, the reaction is highly selective. Mild reaction conditions and various solvents can be used, but trifluoroacetic acid is the preferred. Almost, complete recovery of the trifluoroacetic acid can be achieved by vacuum distillation. The role of trifluoroacetic acid, as well as, of the hydroxylamonium salt suggests a cooperative effect leading to high selective formation of 2-methyl-benzoxazoles. Graphical Abstract: One-pot TFA catalyzed synthesis of benzoxazoles starting from 2-hydroxyacetophenones. (Chemical Equation Presented).
Benzisoxazole 2-oxides as novel UV absorbers and photooxidation inhibitors
Kociolek, Martin George,Casbohm, Jerry S.
, p. 863 - 867 (2013/10/01)
Compounds with strong absorptions in the ultraviolet (UV) region of the spectrum, particularly the UVA and UVB, have seen much interest as UV screeners or absorbers in a wide variety of commercial products. A series of benzisoxazole 2-oxides have been synthesized and characterized by UV-vis spectroscopy. A number of derivatives have been shown to posses moderate to strong molar absorption coefficients in the UVB range (ca. 300 nm), the strongest being those derived from benzophenones. Three other derivatives containing additional electron withdrawing groups showed strong molar absorption coefficients in the UVA (ca. 340 nm). Solvent effects on the parent derivatives show changes in the molar absorption coefficients with little changes in the λmax values. Preliminary studies of these compounds as potential additives to prevent photooxidation of polystyrene showed considerable inhibition of polymer degradation with the parent unsubstituted benzisoxazole 2-oxide compounds being the most effective. Copyright 2013 John Wiley & Sons, Ltd. A series of benzisoxazole 2-oxides have been shown to posses moderate to strong molar absorption coefficients in the UVB range (ca. 300 nm) and three others with strong absorptions on the UVA (ca. 340 nm). Solvent effects of the parent derivatives show changes in the molar absorption coefficients with little changes in the λmax values. Preliminary studies of these compounds as potential additives to prevent photooxidation of polystyrene showed considerable inhibition of polymer degradation. Copyright
Synthesis of 1,2-benzisoxazole 2-oxides
Kociolek, Martin G.,Hoermann, Olivia
body text, p. 2632 - 2638 (2012/08/08)
(Chemical Equation Presented) A series of 2-hydroxyaryl ketoximes were converted to the corresponding 1,2- benzisoxazole 2-oxides by treatment with iodobenzene diacetate (in acetic acid or methanol) or N-chlorosuccinimide in water. Both methods gave moderate to excellent yields for a variety of substituted oximes under mild conditions within short reaction times. The latter method has the advantages of an aqueous solvent and lack of halogenated organic by-products. Copyright Taylor & Francis Group, LLC.
