GB701220A - Method of preparing aldehydes - Google Patents

Abstract

Hydroxyaldehydes are prepared by the action of lithium-aluminium hydride or b , g , d or e lactones in a solvent. The products may be converted to dehydration products of the furan and pyran series. In examples the production of a -methyl-d -hydroxycaproaldehyde or its tautomeric ring-form by the reduction of a -methyl-d -caprolactone, g -hydroxyvaleraldehyde and its tautomer from g -valerolactone, 1 - a - g - dihydroxy - b :b - dimethyl butyraldehyde and its tautomer from pantoyl lactone, 2 - hydroxmethylbenzaldehyde with 1-hydroxyphthalane, from phthalide (1 (3) isobenzofuranone), and g - methyl - g - phenyl - g - hydroxybutyraldehyde or its furane tautomer, from g - methyl - g - phenyl - buty - rolactone, are described; the dehydration of the ring tautomers of the aldehydes, which give hydrazone and other derivatives, but on dehydration behave as the ring compounds, gives the following products: 3:6-dimethyl-5:6 dihydro-(1:4H)-pyran from the 2-hydroxy-3:6-dimethyl (1:4 H) pyran, and 2-benzyl-2:3-dihydrofuran from g -hydroxy-g -benzylbutyraldehyde or its tautomer 2-benzyl-5-hydroxy-tetrahydrofuran; the latter dihydrofuran product may be reduced with Raney nickel to 2-benzyltetrahydrofuran.