3-amino-6-(dimethoxymethyl)pyrazine-2-carbonitrile

2-amino-6-(dimethoxymethyl)-1H-pteridin-4-one

2,4-diamino-6-formylpteridine dimethyl acetal

[(2-acetamido-4-oxo-1H-pteridin-6-yl)-acetyloxymethyl] acetate