Patent ID: 8304380

Claim:
A compound of formula (IVb) wherein R 1 is hydrogen, methyl, or ethyl; R 2 is hydrogen, C 1 -C 6 alkyl, or C 2 -C 6 alkenyl; R 3 is hydrogen, methyl, or ethyl; or either R 1 and R 3 or R 2 and R 3 form together with the carbon atoms to which they are attached a 5- or 6-membered carbocyclic ring; R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are independently selected from hydrogen, C 1 -C 6 alkyl, or C 2 -C 6 alkenyl; or R 4 +R 9 together is a bivalent residue selected from —(CH 2 ) n — wherein n is 1 or 2, —C(═C(CH 3 ) 2 )—, and —C(═C(CH 2 CH 3 ) 2 )—; and R 10 is hydrogen, linear or branched C 1 -C 5 alkyl, or linear or branched C 2 -C 5 alkenyl; R is hydrogen and R′ is selected from hydroxyl or —OCOR 13 , wherein R 13 is hydrogen, or C 1 -C 3 alkyl; R and R′ are selected from methoxy and ethoxy; or R and R′ forming together with the carbon atom to which they are attached dioxolan, dioxane, carbonyl, or C═N—OH; provided that 1-(3a,4,7,7a-tetrahydro-1H-inden-6yl)ethanone, compounds of formula (IVb) wherein R 1 -R 6 , R 8 and R 9 are hydrogen and R 7 is methyl or 2-methyl-pent-2-en-5-yl are excluded.