Question

The final product of which of following reactions furnishes evidence that glucose has an unbranched carbon chain?
A. Glucose `overset(1. Br_(2) // H_(2) O)underset(2. HI//P, heat)rarr`
B. Glucose `overset(1. NaBH_(4))underset(2. HI//P, "heat")rarr`
C. Glucose `underset(underset(3.HI//P,"heat")(2.H_(3)O^(+),"heat"))overset(1.HCN)rarr`
D. All of these

Answer 1

Correct Answer - D
1. `underset(CH_(2)OH)underset(|)overset(CHO)overset(|)((CHOH)_(4))overset(Br_(2)//H_(2)O)rarr underset(CH_(2)OH)underset(|)overset(CO_(2)H)overset(|)((CHOH)_(4))underset(Delta)overset(HI//P)rarr underset("Hexane")underset(CH_(3))underset(|)overset(CH_(3))overset(|)((CH_(2))_(4))`
2. Aldoses (and ketoses) can be reduced with sodium borohydride to compounds called alditols.
`underset("Aldose")underset(CH_(2)OH)underset(|)overset(CHO)overset(|)((CH_(2)OH))underset(underset(H_(2).Pt)(or))overset(NaBH_(4))rarr underset("Alditol")underset(CH_(2)OH)underset(|)overset(CH_(2)OH)overset(|)((CHOH)_(4))`
Reduction of `D-` glucose yields `D-` glucitol
`underset("D-Glucose")underset(CH_(2)OH)underset(|)overset(CHO)overset(|)((CHOH)_(4))overset(NaBH_(4))rarr underset("D-Sorbitol")underset(or)underset("D-Glucitol")underset(CH_(2)OH)underset(|)overset(CH_(2)OH)overset(|)((CHOH)_(4))underset(Delta)overset(HI//P)rarr underset("Hexane")underset(CH_(3))underset(|)overset(CH_(3))overset(|)((CH_(2))_(4))`
3. `underset(CH_(2)OH)underset(|)overset(CHO)overset(|)((CHOH)_(4)) underset(2.H_(3)O^(+),"heat")overset(1.HCN)rarr underset(CH_(2)OH)underset(|)overset(CH(OH)CO_(2)H)overset(|)((CHOH)_(4)) underset(Delta)overset(HI//P)rarr underset("Heptane")underset(CH_(3))underset(|)overset(CH_(3))overset(|)((CH_(2))_(5))`