7,8-Dehydroretinoic acid 7,8-Didehydroretinoic acid 74193-14-9 BRN 6217236 Retinoic acid, 7,8-didehydro- trans-3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-7-yne-2,4,6-nonatrienoic acid