Triphosphate 1c is a potent competitive inhibitor of wild-type HIV-1 reverse transcriptase withKi close to ddATP. The E-isomer 2c is about 30-times weaker. Triphosphates 1c and 2c interactwith the same active site of reverse transcriptase as ddATP. The extent of inhibition of twomutant forms of reverse transcriptase (RT), RTM184V and RTM184I, with triphosphate 1c wasabout 5 and 8 times lower than that of wild-type RTwt.