Assertion: impurity | /r/HasProperty | xiii b
Facets:
Source sentences:
text: The impurities (XIII a) and (XIII b) are thus specific for montelukast sodium (I) prepared by processes using, as the reagent, a salt of [1- (mercaptomethyl)-cyclopropyl]acetic acid with alkali metals (IX) selected from the group of lithium, sodium and potassium.