117333-16-1 Acetamide, N-(2-(3-hydroxy-4-oxo-2,5-cyclohexadien-1-ylidene)ethyl)- N-(2-(3-Hydroxy-4-oxo-2,5-cyclohexadien-1-ylidene)ethyl)acetamide N-Acetyldopamine quinone methide Nada quinone methide