38432-60-9Relevant academic research and scientific papers
New photochemical approaches to the synthesis of chromones
Alvaro, Mercedes,Garcia, Hermenegildo,Iborra, Sara,A. Miranda, Miguel,Primo, Jaime
, p. 143 - 148 (2007/10/02)
Irradiation of the p-methoxyphenyl and p-methylphenyl esters of 2-butynoic, propynoic, 3-(ethylenedioxy)butanoic, 3,3-dimethoxypropanoic and 3-oxobutanoic acids (1-3) affords the corresponding photo-Fries products 4-6. Compound 5a is converted in part into the acetophenone 7a, by way of a Norrish type II photo-reaction, while compound 6a is reluctant to undergo this process, in spite of the fact that it also possess γ-carbonyl hydrogen atoms. From the preparative point of view, the photorearrangement of the esters 1a-d and 2a,c-d is exploitable, while that of 3a proceeds with a lower yield. The differences found in the photochemical behaviour of 2a and 3a show the sharp influence of the acetal group on the course of the reaction. Compounds 4-6 are representative model compounds valuable as direct chromone precursors; in fact, they can be readily cyclized to the chromones 10 under basic or acidic conditions.
Acetoacetylation with 2,2,6-Trimethyl-4H-1,3-dioxin-4-one: A Convenient Alternative to Diketene.
Clemens, Robert J.,Hyatt, John A.
, p. 2431 - 2435 (2007/10/02)
The diketene/acetone adduct, 2,2,6-trimethyl-4H-1,3-dioxin-4-one, efficiently acetoacetylates aliphatic and aromatic alcohols, amines, and thiols.These acetoacetylation reactions are fast and stoichiometric, require no catalysis, and give only volatile byproducts.
