1-[(2R,4S,5S)-4-azido-5-(hydroxyméthyl)tétrahydrofuran-2-yl]-3-[(2S,3S,5R)-2-(hydroxyméthyl)-5-(5-méthyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tétrahydrofuran-3-yl]-5-méthylpyrimidine-2,4(1H,3H)-dione, 3′-(3′-azido-3′-désoxythymidine-3-yl)-3′-désoxythymidine