39575-97-8Relevant academic research and scientific papers
Synthesis of aldehydes and products of such synthesis
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, (2008/06/13)
The disclosure describes the production of complex aliphatic, unsaturated and cycloalkane aldehydes utilizing heterocyclic ring compounds, such as oxazines, particularly dihydro-1,3-oxazines. The oxazines are treated with an alkali metal-alkane compound, such as butyl lithium in the presence of an organic solvent at subzero temperature to form an anion of the oxazine. This anion is then alkylated in the anhydrous reaction mixture by introduction of a suitable halide, epoxide or ketone while still at a subzero temperature and mixture is permitted to warm up to room temperature, following which the reaction mixture is acidified, as with hydrochloric acid to pH 2 to 3, extracted and then made basic, as with caustic alkali with cooling. The reaction mixture is then extracted, as with ether, to produce after evaporation the alkylated dihydro-1,3-oxazine. The alkylated dihydro-1,3-oxazine is then reacted with an alkali metal or sodium borohydride or borodeuteride or borotritide, with cooling to subzero temperatures at about a neutral pH and then transferred into a basic aqueous environment following extraction of the aqueous layer with an organic solvent, such as ether, to give a tetrahydro-1,3-oxazine. This compound may then be converted to the aldehyde desired by steam distillation or by hydrolysis in the presence of a dilute or weak acid, such as hydrochloric or oxalic acid. The aldehydes may then be extracted. These aldehydes are useful as components or intermediates in flavoring or perfumes, in insect attractants and repellants, and in pharmaceuticals.
