A compound of the formula Iin which R1 is H or methyl, R2 is H, methyl or ethyl, R3 and R4 are independently hydrogen, methyl, ethyl, n-propyl or iso-propyl, and the dashed lines representing the alternative possibilities of there being present either an additional double bond or an additional group R5, which is H or methyl.The compounds possess a marine odor with sweet character, and are useful in fine and functional fragrances.
