1-Ribosylpyridine-4-one-3-carboxamide 1beta-D-Ribofuranosylpyridin-4-one 3-carboxamide 3-Pyridinecarboxamide, 1,4-dihydroxy-4-oxo-1-beta-D-ribofuranosyl- 78686-01-8 PCNR compound