4220-52-4Relevant academic research and scientific papers
Pyrrole Chemistry. An Improved Synthesis of Ethyl Pyrrole-2-carboxylate Esters from Diethyl Aminomalonate
Paine, John B.,Dolphin, David
, p. 5598 - 5604 (2007/10/02)
Ethyl pyrrole-2-carboxylates, versatile precursors for the total synthesis of both synthetic model and naturally occurring tetrapyrroles and porphyrins, can be prepared in greatly improved yields by the addition of 1,3-diketones and preformed diethyl aminomalonate to boiling glacial acetic acid.The method is suitable for both small- and large-scale synthesis and has proved far more reliable than the original in situ dissolving zinc reduction of diethyl oximinomalonate discovered by Kleinspehn.Yields range from 60-70percent for the dominant product isomer from unsymmetrical diketones to 75-90percent for the single product derived from symmetrical diketones.Seventeen examples of alkyl-substituted ethyl pyrrole-2-carboxylates are provided.Improved procedures are given for the preparation of the required precursors.
Acylation of Ketone Silyl Enol Ethers with Acid Chlorides. Synthesis of 1,3-Diketones
Tirpak, Robin E.,Rathke, Michael W.
, p. 5099 - 5102 (2007/10/02)
Trimethylsilyl enol ethers of ketones are acylated by a variety of acid chlorides in the presence of zinc chloride or antimony trichloride.The major product of this reaction is the 1,3-diketone resulting from C-acylation.Some O-acylation is observed in most cases.Yields of 1,3-diketones varied but were usually good to excellent.
