for the following products
(1R,2R)-(-)-2-Amino-1-(4-nitrophenyl)-1,3-propanediol | Aminonitrophenolpropanediol | Chloramphenicol base | Chloramphenicol EP Impurity A | Chloromycin base | D-(-)-threo-2-amino-1-(4-nitrophenyl)-1,3-propanediol | L-Base and Levoamine