705. Synthesis of heterocyclic compounds from δ-unsaturated 1 : 3-diketo-esters

Abstract

By GABRA SOLIMAN and LATIF RATEB.Ethyl 6-o-methoxyphenyl-, 6-p-dimethylaminophenyl-, and 6-2'-fury1-2 : 4-dioxohex-5-enoates (11) have been synthesised ; the known methyl and ethyl esters of this series were interconverted by alcoholysis.S i x of these esters were converted into 2 : 6-disubstituted 4-pyrones (V) on bromination, and dehydrobromination with potassium acetate. They were converted into l-phenyl-5-styrylpyrazole-3-carboxylic esters (VI) , the structures of which were determined by ozonolysis, decarboxylation, and hydrolysis to 1-phenylpyrazole-3-carboxylic acid. 3 : 5-Disubstituted isooxazoles (X) have also been prepared.SYNTHESES and properties of &unsaturated 1 : 3-diketo-esters have attracted the attention of various chemists.1 The aromatic prototype, ethyl 2 : 4-dioxo-6-phenylhex-5-enoate (I1 ; R = Et, R' = Ph) was first prepared by Schiff and Gigli and later by R ~h e m a n n . ~ Similarly, Ryan and Algar,4 and Ryan and PlunkettJ5 prepared other hexenoates by the action of sodium on methyl oxalate and substituted methyl styryl ketones (I).The present investigation involves the synthesis of ethyl 6-o-methoxyphenyl-, 6-$dimethylaminophenyl-, and 6-2'-furyl-2 : 4-dioxohex-5-enoates (11) as well as interconversion of the methyl and ethyl esters by alcoholysis. These esters were obtained as described in the Experimental section in good yields unobtainable otherwise. Condensation of $-dimethylaminostyryl methyl ketone gave the desired ester and a high-melting

Synthesis, Biological Evaluation, and Structure−Activity Relationships for 5-[(E)-2-Arylethenyl]-3-isoxazolecarboxylic Acid Alkyl Ester Derivatives as Valuable Antitubercular Chemotypes

“…The residue was purified by flash chromatography to obtain the product. Analytical data for compounds 8, 26 18, 27 and 32 28 matched the data previously published.…”

Design and Synthesis of Some P-Substituted Styrylisoxazole Carboxylic Acid Derivatives as Anti-Inflammatory Agents

“…Adult male albino rats were obtained from animal house of the faculty of Medicine, Assiut University. 10 The appropriate chalcone derivative (1a-g, 0.1 mole) was added portion wise to an icecooled suspension of sodium ethoxide (6.8 g, 0.1 mole) in dry n-hexane (250 mL). Dithyl oxalate (14.6 g, 0.1 mole) was then added dropwise to the resulting mixture and the mixture was further stirred at room temperature overnight.…”

“…The physical and spectral data are listed in Table 1. 10 Glacial acetic acid (100 mL) was added to solution of appropriate ethyl hex-5-enoate derivative (2a-g, 0.0033 mole) in ethanol (100 mL).…”

Transformation of substituted 3-hydroxy-4-[(2E)-3-arylprop-2-enoyl]-1,5-dihydro-2H-pyrrol-2-ones by the action of I2/DMSO into derivatives 2-aryl-5,6-dihydropyrano[2,3-c]pyrrole-4,7-diones

“…3-Hydroxy-1-aryl-1,5-dihydro-2H-pyrrol-2-one (4b) were synthesized by heating esters 1 and Schiff bases (previously obtained from aldehydes and aromatic amines) also in glacial acetic acid as solvent. The representative substratesmethyl 2,4-dioxo-6-arylhex-5-enoates (1{1-2}) [27], aldehydes (2{1-7}), and amines (3{1-7}) are listed on Figure 2.…”