1-(2,3,4-Trideoxy-.beta.-D-glycero-hex-3-enopyranosyl)cytosine 132198-20-0 2(1H)-Pyrimidinone, 4-amino-1-[3,6-dihydro-6-(hydroxymethyl)-2H-pyran-2-yl]-, (2R-cis)- AIDS-002937 AIDS002937 D4C hexose analog