Preparation and Properties of 5,6-monoepoxyvitamin a Acetate, 5,6-monoepoxyvitamin a Alcohol, 5,6-monoepoxyvitamin a Aldehyde and Their Corresponding 5,8-monoepoxy (furanoid) Compounds.

1. Oxidation of vitamin A acetate with monoperphthalic acid gave 5,6-monoepoxyvitamin A acetate, C(22)H(32)O(3), obtained as pale-yellow crystals, m.p. 65-66 degrees . 2. Saponification of 5,6-monoepoxyvitamin A acetate yielded 5,6-monoepoxyvitamin A alcohol, which was readily oxidized with manganese dioxide to 5,6-monoepoxyvitamin A aldehyde, obtained as yellow crystals, m.p. 101-102 degrees . It was the most stable of all the epoxy compounds studied. 3. Treatment of the 5,6-epoxy compounds with ethanolic hydrochloric acid gave the corresponding 5,8-epoxy (furanoid) compounds. 5,8-Monoepoxyvitamin A aldehyde was obtained as crystals, m.p. 104-105 degrees , but was very unstable. 4. Crystalline semicarbazones and phenylhydrazones with constant melting points and characteristic spectra were prepared from 5,6- and 5,8-monoepoxyvitamin A aldehyde. 5. Reduction of 5,6- and 5,8-monoepoxyvitamin A aldehyde with lithium aluminium hydride gave the corresponding 5,6- and 5,8-monoepoxyvitamin A alcohol. 6. 5,6- and 5,8-Monoepoxyvitamin A aldehyde were fed to vitamin A-deficient rats, and the compounds obtained from the livers of rats were indistinguishable from the reduction products obtained with lithium aluminium hydride. 7. The structures of the epoxy compounds were confirmed by their chromatographic behaviour, elemental analyses, ultraviolet-, visible- and infrared-absorption spectra and nuclear-magnetic-resonance spectra.