Synthesis and Chemistry of Tetronic Acids

Reactivity Control in the Addition of N,N′‐Dialkylated 1,n‐Diamines to Activated Skipped Diynes: Synthesis of Fused Bicyclic 1,4‐Diazepanes and 1,5‐Diazocanes

“…The structure of this secondary compound, which reveals a higher structural complexity than that expected for a sequential double aza-Michael addition onto the diyne, represents an unexpected and novel chemical outcome for the array of functionalities present in skipped diyne 1a. From a biological (pharmacological) point of view, this novel structure incorporates relevant pharmacophore motifs; that is, a butenolide ring, [10] a 4-aminotetronic acid, [11] and a 1,4-diazepane ring. [12] On the other hand, from a chemical point of view, the structure accommodates a high functional density on a minimal skeletal connectivity, supporting a reactivity profile steered by the α-benzoyl-substituted butenolide ring and the two chemically differentiated conjugated N-methyl enamines.…”

3-Acyltetramics Acids: A Brief Approach on Biological and Synthetical Aspects

“…A preferência por tal tautômero pode ser comprovada por análises de infravermelho desta classe de compostos, onde se veem as absorções referentes aos estiramentos axiais da ligação C=O das carbonilas de cetona em C-4 e de lactama em C-2, em 1782 cm -1 e 1696 cm -1 , respectivamente, assim como a absorção referente ao estiramento axial da ligação N-H em 3230 cm -1 . 1,9 Em contrapartida, os ácidos 3aciltetrâmicos (Figura 3b) apresentam maior acidez em relação aos ácidos não substituídos em C-3, com valores de pK a na faixa entre 3,0 e 3,5, 10 o que favorece sua enolização completa, sendo então as formas enólicas as preferenciais.…”

4-Benzyloxy-1-oxaspiro[4.6]undec-3-en-2-one

“…The synthesis and structural analysis of related derivatives continues to be of significant interest. Although several methodologies have been reported for their preparation, most of them use expensive organic starting materials as the synthesis is complex (Tejedor & García-Tellado, 2004). -Hydroxyesters and their cycloalkane derivatives can be easily prepared and then used for the direct synthesis of butenolides (furan-2[5H]-ones) through an addition followed by a Wittig olefination reaction using the accumulated ylide Ph 3 P=C=C=O; the use of cycloalkane--hydroxyesters allows the preparation of spiro systems of analogous substances with antiviral and anticancer activities among their most important properties (Schobert, 2007).…”