Question

3) Show the formation of cyclic glucose from liner glucose (C6H1206). (Use arrow pushing mechanism 4) Identify A and B molecules as D or L isomer. Give the IUPAC names for A and B molecules. H Н. HO -H H- -OH H- -ОН HO- -C-H H -ОН. CH2OH HO- -H CH2OH A B

Answer 1

$\large \bf (3)$

$\bf \text{The linear form of glucose makes up less than } 3\%\text{ of the glucose}\\ \text{ molecules in a water solution.}$$\bf\text{The cyclic form of glucose is formed when the hydroxyl group of }\\ carbon-5(C-5) \text{ bonds to the aldehyde }carbon-1(C-1)$

Н. 0 6CH,он H 6 СН,ОН 2 5 ОН H 21 H—С — ОН 31 НОЯС — Н 1 НЕС — ОН 3 1 ОН ОН 2 2 НО н* НО 3 ОН 3 Hd — ОН ОН ОН | 6 CH, OH Cyclic Glucose Linear Glucose
$\large \bf (4)$

$\text{ If OH on the bottom chiral center points to the \underline{right}, the sugar is \bf D.}$$\text{ If OH on the bottom chiral center points to the \underline{left}, the sugar is \bf L.}$

$\text{ Here both A and B are L isomers.}$

$\bf \text{IUPAC name of A:} \;2,3,4-Trihydroxybutanal$

$\bf \text{IUPAC name of B:} \;2,3,4,5,6-Pentahydroxyhexanal$