Doxofylline Impurity 5 Catalogue D349275 CAS 2095554-12-2 M.W 284.27 M.F C11H16N4O5 Specifications FAQs 1-((1,3-dioxolan-2-yl)methyl)-4-(1,3-dimethylureido)-1H-imidazole-5-carboxylic acid