Name: Hormones
Uploaded: 2019-07-19
Duration: 2 min 32 s
Description: Hormones are chemical compounds with high biological importance. They are secreted by different glands in the human body. Let's explore this combo of biology...

Question

Discuss the structure of glucose on the basis of its chemical properties.

Accepted Answer

1. The molecular formula of glucose is found to be $C_{6} H_{12} O_{6}$ . It can be written as $CHO - {(CHOH)}_{4} - {CH}_{2} OH$ .
2. Acylation of glucose with acetic anydride gives glucose pentacetate. Hence, glucose molecule has five $- OH$ groups.
$\underset{Glucose}{CHO - {(CHOH)}_{4} - {CH}_{2} OH} \overset{{({CH}_{3} CO)}_{2} O}{\to}$ $\underset{glucose pentacetate}{(CHO) - {({CHOCOCH}_{3})}_{4} - {CH}_{2} O . {COCH}_{3}}$

3. Glucose reacts with hydroxylamine and hydrogen cyanide forming corresponding oxime and cyano hydrin respectively. Hence, glucose molecule has carbonyl group.

4. Glucose on oxidation with tollen's reagent and fehling's solution gives gluconic acid. Hence, carbonyl group present in glucose is aldehydic group.

$\underset{Glucose}{{CH}_{2} - OH - {(CHOH)}_{4} - CHO} \to_{Tollen' s reagent}^{(O)} \underset{Gluconic acid}{({CH}_{2} OH) - {(CHOH)}_{4} - COOH}$

5. Glucose on oxidation with nitric acid gives glucaric (saccharic) acid. This suggests that glucose molecule has primary alcoholic group $(- {CH}_{2} OH) .$

$\underset{Glucose}{{CH}_{2} OH - {(CHOH)}_{4} - CHO} \to_{{NHO}_{3}}^{(O)} \underset{glucaric acid}{COOH - {(CHOH)}_{4} - COOH}$

6. On reduction with $HI$ , glucose gives n - hexane.

$\underset{Glucose}{{CH}_{2} - OH - {(CHOH)}_{4} - CHO} \to_{(H)}^{HI} \underset{n - hexane}{{CH}_{3} - {({CH}_{2})}_{4} - {CH}_{3}}$

This reaction suggests that all six carbon in glucose are linearly linked.
7. Open chain structure of glucose:
Based on above observations, glucose is given the open chain structure.

Discuss the structure of glucose on the basis of its chemical properties.

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