Synonyms: .alpha.-L-(+)-(2R,5R)-1-[2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine;.alpha.-L-Oxathionyl-cytidine;2(1H)-Pyrimidinone, 4-amino-1-(2-(hydroxymethyl)-1,3-oxathiolan-5-yl)-, (2R-trans)-;2(1H)-Pyrimidinone, 4-amino-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]-, (2R-trans)-;alpha-L-(+)-(2R,5R)-1-(2-(Hydroxymethyl)-1,3-oxathiolan-5-yl)cytosine;alpha-L-Oxathionyl-cytidine;trans-2-Hydroxymethyl-5-(cytosin-1-yl)-1,3-oxathiolane