Identify the Correct set of stereochemical relationships amongst the following monosaccharides I-IV I II III… · ABC26OR0497
Subject: Organic Chemistry · Chapter: Natural Products · Topic: Natural Products & – General · Exam: GATE 2000-2022 · Marks: 2 · Difficulty: Medium
Identify the Correct set of stereochemical relationships amongst the following monosaccharides I-IV 
I II III IV
I II III IV(a)I and II are anomers; III and IV are epimers
(b)I and III are epimers; II and IV are anomers
(c)I and II are epimers; III and IV are anomers
(d)I and III are anomers; I and II are epimers.
Answer
Answer: D ✓ checked by 4AB · confidence high
Key D verified: I/III are anomers (C-1) and I/II are C-4 epimers; the explanation was missing.
Explanation
I = methyl α-D-glucopyranoside (OMe axial); II = methyl α-D-galactopyranoside (C-4 OH axial); III = methyl β-D-glucopyranoside; IV = methyl β-D-galactopyranoside. I/III and II/IV differ only at C-1, so they are anomers. I/II and III/IV differ only at C-4, so they are epimers. Options (a), (b) and (c) each state a false relation; (d) 'I and III are anomers; I and II are epimers' is correct.
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