13375-17-2Relevant academic research and scientific papers
Synthesis of alpha-alkoxycarboxylic acids
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, (2008/06/13)
Numerous alpha-carboxylic acids are prepared in a liquid medium by the reaction of an organic compound having at least one reactive hydroxyl or thiol group, with a monoketone, and a haloform, in the presence of a phase transfer catalyst and an alkali metal hydroxide. The term "alpha-alkoxycarboxylic acids" includes alpha-phenoxycarboxylic acids, alpha-thioalkoxycarboxylic acids and alpha-thiophenoxycarboxylic acids. Specific substituents on the beta carbon atom of an alpha-alkoxycarboxylic (or "2-alkoxycarboxylic") acid reaction product formed in this novel synthesis, are introduced by appropriate choice of the ketone reactant; alkoxy and phenoxy substituents on the alpha carbon atom of a 2-alkoxycarboxylic acid are introduced by appropriate choice of the organic compound having a hydroxyl or thiol group. De-alkoxylation of the 2-alkoxycarboxylic acid yields alpha-beta monoolefinically unsaturated carboxylic acids which are necessarily alpha substituted, and may also be beta-substituted. It is now possible to produce, simply and conveniently, numerous substituted alpha-beta monolefinically unsaturated carboxylic acids with a variety of substituents on the alpha carbon atom, and, optionally on the beta carbon atom of these substituted carboxylic acids. Esters may also be conventionally derived from both the 2-alkoxycarboxylic acids, and the unsaturated carboxylic acids. During the phase transfer catalyzed synthesis of this invention, an intermediate acyl halide derivative is formed prior to the formation of the 2-alkoxycarboxylic acid reaction product. The formation of the acyl halide derivative allows the subsequent direct formation, in a modification of the same reaction, of 2-alkoxycarboxylic acid amides (or "2-alkoxycarbamides"), simply by adding a primary or secondary amine to the reaction mass. By dealkoxylation of the 2-alkoxycarbamides, specific, necessarily alpha-substituted and optionally beta-substituted acrylamides are synthesized which previously could be prepared, if at all, only with difficulty.
