New intermediates, process for their preparation, and their use for the synthesis of vitamins A and E

摘要

New intermediates and processes for the preparation of vitamins A and E, which are the acetals of 5,6-dihalo-3-methyl-3-hydroxyhexanal or of 6-halo-3-hydroxy-3-methyl-5-hexenal or 3-methyl-3-hydroxy-5-hexenal, as well as processes for making the intermediates. After dehydrohalogenation and dehydration these intermediates are condensed directly with beta -ionone or with 2-methyl-2-heptene-6-one to synthesize vitamins A and E respectively.