Reactions of cyclic oxalyl compounds XXXIX. Reactions of 4-Ethoxycarbonyl-5-phenyl-2,3-dihydrofuran-2,3-dione with heterocumulenes andSchiff bases

Crystal structure and computational studies of (3Z)-4-benzoyl-3-[(2,4-dinitrophenyl)hydrazinylidene]-5-phenylfuran-2(3H)-one

“…The reactions of substituted furan-2,3-diones with dienophiles in different solvents and at various temperatures have also been studied (Kollenz et al, 1984a,b). Moreover, derivatives of heterocyclic 2,3-diones which are also ,-unsaturated carbonyl compounds have been found to serve as versatile synthetic equivalents in thermolysis reactions (Fulloon et al, 1995;El-Nabi & Kollenz, 1997;Kollenz et al, 2001), cycloaddition reactions (Kollenz et al, 1987) and nucleophilic addition reactions (Kollenz et al, 1977;Altural et al, 1989). Several attempts to change functional groups in furan-or pyrrol-2,3-diones and related systems have been reported (Fabian & Kollenz, 1994;Wong & Wentrup, 1994).…”

Chemistry of α-Oxoesters: A Powerful Tool for the Synthesis of Heterocycles

“…Pyrrol-2,3-diones 138 was synthesized by reaction of 4-ethoxycarbonyl-2,3-furandione with arylisocyanates at 70 °C. First, a seven-membered ring system 137 was generated as an intermediate, which underwent decarboxylation at the same temperature to produce the corresponding pyrrol-2,3-diones 138 in 75–85% yields (Scheme ) …”

“…By heating a solution of 4-ethoxycarbonyl-5-phenyl-2,3-dihydrofuran-2,3-dione in xylene in the presence of a heterocumulene or Schiff base under reflux conditions for 1.5 h, 5-ethoxycarbonyl-4 H -1,3-oxazine-4-ones 947 – 949 were obtained in 35–70% yields, via [4 + 2] trapping of in situ generated α-oxoketene as a reaction intermediate (Scheme ) . Stadler et al described a similar [4 + 2] cycloaddition reaction between carbomethoxypivaloylketene, generated by FVP of 5- t -butyl-4-methoxycarbonyl-2,3-dihydrofuran-2,3-dione, and heterocumulenes and Schiff base for the construction of corresponding 4 H -1,3-oxazine derivatives in 32–53% yields.…”

A CONVENIENT ONE POT SYNTHESIS OF PYRIDO[2,3-d]- PYRIMIDINES AND PYRIMIDO[2,3-c]PYRIMIDINES (N5-DEAZAPETRINS)

“…Although, Wood et. It is worth mentioning that synthesis of fused azoles and azines via simple routes and unexpensive starting materials is a matter of our interest (16)(17)(18). (13) proposed a rule that the most reactive position of the pyrimidine, the 5-position, will condense first with the most reactive site in electrophilic reagent, some authors (14) propose a revision of this rule by saying that the 6-amino nitrogen will condense first followed by annelation with the 5-position.…”