185026-88-4Relevant academic research and scientific papers
Ring opening reactions of pyridinium- and phosphonium betaines of squaric acid in alkaline media
Gruenefeld, Johann,Jones, Peter G.
, p. 718 - 724 (2007/10/03)
Pyridiniumtrioxocyclobutylides 1 bearing electron-donating substituents undergo ring opening reactions at the four-membered ring in alkaline media. The structure of one of the resulting bisacyl ylides 3 is confirmed by X-ray analysis. In acidic media 3 are easily hydrolyscd forming quaternary pyridinium salts of pyruvic acid 6; the existence of a stable gem-diol form 5 in the crystalline state is also proved by X-ray analysis. Triphenylphosphoniumtrioxocyclobutylide (8) gives the bisacyl ylide 9, which is hydrolysed to (triphenylphosphor-anylidene)pyruvic acid (10). Johann Ambrosius Barth 1996.
