5-Deoxy-5-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo(g)pteridin-10(2H)-yl)-L-ribose 59224-04-3 7,8-Dimethyl-10-(2,3,4-trihydroxy-4-formylbutyl)isoalloxazine Riboflavinal Vitamin B2 aldehyde