Droxidopa Impurity 6 2-(3,4-dihydroxyphenyl)-2-hydroxy-acetaldehyde Droxidopa Impurity 4 N-Hydroxyphthalimide 3,4-Di-O-benzyl DL-threo-Droxidopa Hydrochloride 3,4-Di-O-benzyl DL-erythro-Droxidopa Hydrochloride 1,3-Benzodioxole-N-phthaliMido DL-threo-Droxidopa-13C2,15N Paclitaxel Impurity 8 MLMBILXCWROGFT-YVOIDUNUSA-N D-Threo-Dihydroxyphenylserine N-Benzyloxycarbonyl DL-threo-β-(3,4-Methylenedioxyphenyl)serine Droxidopa Impurity 8 QNECLCOECOXTEW-BDAKNGLRSA-N Tyrosine, b-hydroxy-3-methoxy- 3,4-Di-O-benzyl DL-threo-Droxidopa-13C2,15N Hydrochloride Droxidopa Impurity 31 (2S,3R)-3-(3,4-Dihydroxyphenyl)-3-hydroxy-2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)propionic acid FFEWFMCABUNGJJ-OPABSIBTSA-N