1-(3-Azido-2,3-dideoxy-.beta.-D-threo-pentofuranosyl)uracil 101039-96-7 2,4(1H,3H)-Pyrimidinedione, 1-(3-azido-2,3-dideoxy-.beta.-D-threo-pentofuranosyl)- AIDS-001162 AIDS001162 AZU(up) AZddU (threo)