John M. Gruber

Epoxidation of retinol and the structure of “chromogen 574”

Epoxidation of retinol (vitamin A alcohol, 1) with freshly prepared and standardized mono-perphthalic acid in ether affords a product which Karrer named “chromogen 574” in 1945. Repetition of this peracid oxidation of retinol (1) with several peracids (m-PPA, m-CPBA, or CH3CO3H) with or without a buffer (NaHCO3 or Na2HPO4) produces dihydropyran alcohol 4 as characterized by spectroscopy and subsequent chemical transformations. Thus the structures proposed for “chromogen 574” by Karrer in 1945–47 and Troitskii in 1948 are now revised to correspond to cyclic alcohol 4.

Total syntheses of (±)-cycloseychellene and (±)-seychellene

Abstract Total syntheses of (±)-cycloseychellene (1) and (±)-seychellene (2) from 2,5-dimethylcyclohexanone (3) are described.