(6S)-6-Methoxy-3-[(5-methyl(1,3,4-thiadiazol-2-ylthio))methyl]-5-oxo-6-(2-(1,2,3,4-tetraazoyl)acetylamino)-2H,6aH-azetidino[2,1-b]1,3-thiazine-4-carboxylic acid AIDS-085771 AIDS085771 LY127160