Fundamentals of Organic ChemistryChemistryBiomolecules
Which of the following statements regarding the given structures is true? (i) (ii) (iii)
Options
- AOnly structures (i) and (ii) are epimers.
- BStructures (i) and (ii) are epimers, and structures (i) and (iii) are epimers.
- CAll three structures are epimers of each other.
- DOnly structures (i) and (iii) are epimers.
Correct answer
B. Structures (i) and (ii) are epimers, and structures (i) and (iii) are epimers.
Step-by-step solution
Epimers are diastereomers that differ in configuration at exactly one stereocenter. Let us compare the given structures: Structure (i) is D-glucose. Structure (ii) is D-galactose. Structure (iii) is D-mannose. Comparing structure (i) and structure (ii): They have the same configuration at C2, C3, and C5, but differ in configuration only at C4. Therefore, structures (i) and (ii) are C4 epimers. Comparing structure (i) and structure (iii): They have the same configuration at C3, C4, and C5, but differ in configuratio