1-[[[1-[3-[2-l]-3-[2-(1-hydroxy-1-methylethyl)phenyl]propyl]sulfinyl]methc cid;|Montelukast EP Impurity C ; Montelukast USP Related Compound A ; Montelukast Sulfoxide ; Montelukast S-Oxide ; [1-[[[1-[3-[(E)-2-(7-chloroquinolin-2-yl)ethenyl]phenyl]-3-[2-(2-hydrox-ypropan-2-yl)phe|Montelukast S-Oxide|Montelukast Sulfoxide ;|Montelukast Sulfoxide;|Montelukast USP Related Compound A ;|Montelukast USP Relatedcompound A;