pyridiniumtrioxocyclobutylide;pyridinium betaine of squaric acid;2-(1-pyridino)-3,4-dioxo-1-cyclobutenol;3,4-Dioxo-2-pyridin-1-ium-1-ylcyclobuten-1-olate
Eine neue Klasse von Stickstoff-Betainen der Quadratsäure
作者:Arthur H. Schmidt、Amokrane Aimène、Martin Schneider
DOI:10.1055/s-1984-30868
日期:——
Synthese von Glutaconaldehyden aus Quadrats�ure-Pyridiniumbetainen
作者:J. Gr�nefeld
DOI:10.1002/prac.19933350308
日期:——
The pyridinium ring of squaric acid betaines (2) is opened by hydroxide ions. Electronegative substituents (R = Cl, CN) at C-3 promote this reaction. The stereochemistry of the resulting 5-(2-hydroxy-3,4-dioxocyclobut-1-en-1-yl) aminopenta-2,4-dienales (3) is confirmed by NMR-spectroscopy. Treatment of 3 with sodium hydroxide results in further hydrolysis to the sodium salts of glutaconaldehydes (5) and 3-amino-4-hydroxycyclobut-3-ene-1,2-dione (6). These products are also directly obtained from the nicotinic acid derivates 2d (R = COOEt) and 2e (R = CONH2), in the latter case cyclisation of the glutaconic acid derivate to the known 3-formylpyrid-2-one (10) is observed.
GRUENEFELD, J.;ZINNER, G., CHEM.-ZTG, 1984, 108, N 3, 112
作者:GRUENEFELD, J.、ZINNER, G.
DOI:——
日期:——
SCHMIDT, A. H.;AIMENE, AMOKRANE;SCHNEIDER, M., SYNTHESIS, BRD, 1984, N 5, 436-439