1,3,3-Trimethylnorbornan-2-one 11000-29-6 7787-20-4 Bicyclo(2.2.1)heptan-2-one, 1,3,3-trimethyl-, (1R,4S)- Bicyclo(2.2.1)heptan-2-one, 1,3,3-trimethyl-, (1theta)- EINECS 232-107-5 L-Fenchone l-alpha-Fenchone