A compound of the formula (I) in which, independently, R1 is selected from H and methyl; R2 is selected from H, and methyl; R3 is selected from H, methyl and ethyl; R4 is selected from H, methyl and ethyl; or R3 and R4 together form a ring in which n is 1 or 2. The compounds have the characteristic desirable odour qualities of the Damascone® molecules, but lack their disadvantageous skin sensitization effects.