Alkyl Carbonates in Synthetic Chemistry. II. Condensation with Ketones. Synthesis of β-Keto Esters¹

GP96 C‐terminal improves Her2/neu DNA vaccine

“…Ethyl naphthalene‐2‐carbonyl acetate (1 A‐Na) :66 Same procedure as for 1 A‐Bi, but with naphthalene‐2‐carbonyl chloride (952.5 mg, 5 mmol). Purified by CC (C 6 H 12 /CH 2 Cl 2 , 50:50 to 0:100).…”

Total synthesis of the macrocyclic lactone, dideoxyzearalane

“…Further purification was achieved by extraction of the hydroxy acid into aqueous sodium bicarbonate solution, reacidification, and reextraction into chloroform. Removal of the solvent gave 15.6 g (90%) of (+) 7a as a yellow oil: [ajL'e +5°(c 1, CH3OH); nmr (CDC13), 8.0-8.2 (m, 1, aromatic proton), 7.0-7.7 (m, 3, aromatic protons), 6.8-7.0 (m, 2, COOH) and COH), 3.5-4.2 (m, 1, OCH), 2.8-3.3 (crude t, 2, ArCH2), and 1.1-2.0 ppm (m, 19,CCH2C and OCCH3, the CH3 doublet is visible, centered at 1.2 ppm, J = 6 Hz); ir (film), 3325 (OH) and 1690 cm-1 (C=0); uv max (CH3OH), 230 µ (e 7100) and (1400).…”

β-Keto esters from ketones and ethyl chloroformate: a rapid, general, efficient synthesis of pyrazolones and their antimicrobial, in silico and in vitro cytotoxicity studies

“…There are methods to synthesize β-keto esters from ketones like caboxylation of ketone enolates [52-54] using carbon dioxide and carbon monoxide sources in the presence of palladium or transition metal catalysts. Currently, the most general and simple method to synthesize β-keto ester is the reaction of dimethyl or ethyl carbonate with ketone in the presence of strong bases [55,56]. This method requires long reaction time, use of excessive amount of reagent and inconsistent yield.…”