(3aR,4R,6R,6aR)-6-((E)-4-(hydroxyimino)-2-oxo-3,4-dihydropyrimidin-1(2H)-yl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)methylisobutyrate cas 2346620-55-9 powder