622. EMERSON, W. S., AND LONGLEY, R. I., Jr. (Monsanto Chemical Co.). Oxo Aldehydes. United States Patent 2,624,764. Jan. 6, 1953. Chem. Abs., vol. 47, 1953. p. 11,234.

Patent Abstracts

Hydrolysis of alkoxydihydropyrans (I) prepared by condensing acroleins or vinyl ketones and vinyl ethers in the presence of an acid in a solvent and at temperatures slightly above normal room temperature yields oxo aldehydes. Thus, 2-ethoxy-2methyl-3, 4-dihydron-2H-pyran. 50 gm., H₂O 100, and concentrated HCl 10 ml. are stirred 30 min. at 20º-40º, neutralized with NaHCO₃, saturated with NaCl, extracted 3 times with Et₂O 100 ml., the extracts diluted with hexane 150 and C₆H₆100 ml., the EtO₂ distilled, the residue refluxed under a Dean and Strak trap to remove H₂O and EtOH, and distilled in a Lecky-Ewell column to give 31 gm. 5-oxoxhexanal, b₁₅, 87º-89º. Similarly prepared are the following hexanals: 5-oxo-3-phenyl, b₂ 133º-137º, 5-oxo-s-methyl, 5-oxo-3-methyl. In addition, preparation of 5-oxo-3-(2-furyl)-5-phenyl and 5-oxo-5cyclohexylpentol were reported by analogons methods.