10H-Benzo(4,5)cyclohepta(1,2-b)selenophen-10-one, 4,9-dihydro-4-(1-methyl-4-piperidinylidene)- 135472-91-2 4,9-Dihydro-4-(1-methyl-4-piperidinylene)-1-hydroxybenzene-4,5-cyclohepta-1,2b-selenophen-10-one BN 52256 BN-52256