Fundamentals of Organic ChemistryChemistryGeneral Organic Chemistry
Which of the following pairs represent examples of diastereomers? (I) (+)-Tartaric acid and meso-tartaric acid (II) Maleic acid and fumaric acid (III) D (+) -Galactose and D (+) -mannose (IV) (+)-Lactic acid and (-)-Lactic acid
Options
- A(I), (II) and (III)
- B(IV) only
- C(I), (III) and (IV)
- D(I) and (III)
Correct answer
A. (I), (II) and (III)
Step-by-step solution
Diastereomers are stereoisomers that are not mirror images of each other. (I) (+)-Tartaric acid and meso-tartaric acid are stereoisomers but not mirror images, hence they are diastereomers. (II) Maleic acid (cis-butenedioic acid) and fumaric acid (trans-butenedioic acid) are geometrical isomers. Geometrical isomers are a class of diastereomers because they are stereoisomers that are not mirror images. (III) D (+) -Galactose and D (+) -mannose are aldohexoses that differ in the spatial arrangement of atoms at one or