ChemInform Abstract: A Novel Method for the Synthesis of 4H‐Pyran‐4‐one Derivatives.

Abstract

A Novel Method for the Synthesis of 4H-Pyran-4-one Derivatives. -Bromomethyl-, acetoxymethyl-, and hydroxymethyl derivatives of 4H-pyranone are synthesized by appropriate functionalizations of 2,6-dimethylpyranone derivative (III), which can be obtained by condensation of magnesium acetonedicarboxylate chelate complex (I) with acetic anhydride. -(SHAHRISA, A.; TABRIZI, R.; AHSANI, H. R.; Org.

New series of ɣ-pyrone based Podands: synthesis, characterization and study of their application in acetate salts cation trapping in nucleophilic substituted reactions

“…24 In this method, esterification of chelidonic acid with the appropriate alcohol was performed in the presence of an inorganic or Lewis acid. In a modified procedure, 25 to improve the yield of product, we prepared via esterification the methyl and ethyl dialkyl oxalates from oxalic acid with methanol and ethanol, respectively. Condensation of obtained dialkyl oxalates with acetone in the presence of alcoholic solution of related base gave dialkyl-2,4,6-trioxoheptanedioate.…”

“…Synthesis of dialkyl 4-oxo-4H-pyran-2,6-carboxylates 4 via the traditional method (Route A); 24 and via the modified procedure (Route B). 25 Subsequently, the dialkyl 4-oxo-4H-pyran-2,6-dicarboxylates 4a and 4b were reacted with a variety of glycol monoalkyl ethers in dry toluene in the presence of catalytic amount of sodium methoxide. Since the use of a 1:1 stoichiometry of reactants led to unreacted starting materials or only trace amount of the desired product (Table 1, entry 1), we optimized the reaction conditions by screening different ratios of 4a:5a (Table 1).…”

“…Trioxoheptanedioic acid dialkyl esters were prepared according to the procedure reported previously; 25 A mixture of the appropriate trioxoheptanedioic acid dialkyl ester 3 (0.13 mol) with the corresponding dry alcohol (300 mL) and concentrated hydrochloric acid (7 mL) was refluxed for 40 min. After that time the reaction mixture was cooled to r.t., filtered and the collected solid was further purified by recrystallization from alcohol.…”