Unverified50% confidenceFactExact time
In the thalidomide (Contergan) incident, the (R)-configuration had a sedative effect, while the (S)-configuration caused severe teratogenicity; this incident prompted regulatory agencies in various countries to require that chiral drugs must have their stereochemical composition clearly defined and be marketed as a single enantiomer whenever possible.
1
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50%
Confidence
Long-term
Relevance
10/12/2026
First Seen
Sources
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Related Claims
UnverifiedThe R-form enantiomer of thalidomide has an antiemetic effect, while the S-form enantiomer is strongly teratogenic, and the two forms also interconvert within the body.75% similarUnverifiedIn the positive nonlinear effect mechanism, homochiral combinations (R-R or S-S) have higher asymmetric induction ability, while heterochiral combinations (R-S) have lower activity, enabling catalysts of modest chiral purity to still yield high-purity products.64% similarUnverifiedTraditional chemical synthesis of chiral compounds usually yields a racemic mixture of equal parts R and S, because achiral reagents or achiral catalysts cannot distinguish between the two enantiofaces.63% similar
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