60705-25-1Relevant articles and documents
Reactions of pyrrolidine enamines of cyclic and acyclic 3,4-dioxobutanoic acid derivatives with dimethyl acetylenedicarboxylate. A new case of atropoisomerism
De Ancos, Begona,Carmen Maestro,Rosano Martin,Mateo, Ana I.
, p. 13857 - 13864 (1994)
Reaction conditions and structure of the starting enamines (cyclic or open-chain) determine greatly the final products of the title reactions. Whereas in benzene and acetonitrile, DMAD and 1 give a mixture of the diastereoisomeric dienamines 5, in methanol they afford pirrolizine 3. Enaminofuranones 2 and 10 furnish in the corresponding 'Michael adducts' 7a,b,c and 11a,b,c but fail to yield pirrolizines. It has been demonstrated that above b and c adducts differ exclusively on the arrangement of groups around a chiral axis.
SINTESIS Y REACCIONES CON AMIDINAS DE DERIVADOS CICLICOS Y DE CADENA ABIERTA DEL ACIDO 2-BROMO-3,4-DIOXOBUTANOICO.
Ancos, B. De,Delgado, F.,Martin, M. R.
, p. 413 - 420 (2007/10/03)
Bromination of enaminoesters 1 and 5, in appropriate conditions, affords in good yield enamines of the corresponding 2-bromo-3,4-dioxobutanoic acid derivatives 2-3 and 6 or dibromocompounds 4 and 6.The open chain enaminoesters (1-3) are more easily hydrolyzed that enaminofuranones 5 and 6.Prolongated treatment of 6 with hydrochloric acid affords the chlorinated enamine 11.The synthesis of 3-Bromo-4-hydroxy-5-methoxyfuran-2(5H)-one 10 can be achieved by bromination of 12, obtained by hydrolysis of 5.The reaction of methyl 3-bromo-4,4-dimethoxy-3-oxobutanoate with amidines is a good method for the synthesis of 5-bromo-6-(dimethoxymethyl)pyrimidin-4(3H)-ones substituted at 2 position.Under the same conditions the reaction of furanone 10 with benzamidine does not lead to the corresponding imidazoline. - Keywords: enaminoesteres, 4-aminofuranonas, bromacion, hidrolisis, pirimidonas.