(+)-1-[(1S,4S)-2,3-Dideoxy-2,3-difdehydro-3-fluoro-.beta.-L-ribofuranosyl]thymine .beta.-L-Thymidine, 2',3'-didehydro-3'-deoxy-3'-fluoro- 1-(3-Fluoro-2,3-dideoxy-B-L-glycero-pent-2-enofuranosyl)thymine AIDS-043677 AIDS043677 L-3'-FD4T