TABLE Dextrose. Figure 1.1- Glucose anonymous http\en.qsstudy .org.com

TABLE OF CONTENTS
CONTENTS PAGE

1-INTRODUCTION………………………………………………. 01
Glucose………………………………………………………. 01
2-HISTORY………………………………………………………. 01
3-STRUCTURE…………………………………………………… 01
Structure………………………………………………………… 02
4-FORMS OF GLUCOSE…………………………………………. 02
Open chain form………………………………………………….. 02
Ring form………………………………………………………… 03
5-REPRESENTATIONS……………………………………………. 03
Fischer Formula…………………………………………………. 03
Haworth Formula……………………………………………….. 05
6-BOAT AND CHAIR FORMS……………………………………. 07
7-REFERENCES…………………………………………………… 08

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1-Introduction
Glucose
Glucose is a simple sugar with molecular formula of C6H12O6.glucose monosaccharide which is subcategory of carbohydrates.it is energy source that the body most readily uses. glucose is a sugar that store in the muscles for use. glucose can be obtained by hydrolysis of carbohydrates such as milk, sugar, maltose etc.it is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight.it is also known as Dextrose.
Figure 1.1- Glucose
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2-History
Glucose was first isolated from raisins in 1747 by the German Chemist Andreas Marggraf . glucose was discovered in grapes by J.T.Lowitz in 1792 and recognized as different from cane sugar (sucrose).glucose is term coined by J.B.Dumas in 1838. A.Kekule proposed the term dextrose because in aqueous solution of glucose ,the plane of linearly polarized light is turn to right. But in other way ,D-Fructose and L-Glucose turn polarized light to the left. In 1902.Emil Fischer got noble prize for his finding the term glucose and he also established the stereochemical configuration of all kJJnown sugars and isomers.
3-Structure
Glucose is a monosaccharide with formula C6H12O6whose five hydroxyl(OH) groups are arrange in specific way along its six-carbon back.it is closed pyran ring. On the other hand ,it has open chain which are mostly merge by mutarotation.
Sugar are classified according to two properties.
• numbers of carbon atoms
• type of functional group (either an aldehyde or a ketone group)
Glucose which has six carbon atoms (hexose sugar) and contain an aldehyde group(-CHO) which referred as an Aldohexose. (K.Kamide ,Elesevier ,2005,Cellulose and cellulose derivatives, Wikipedia .com)
4-Forms of Glucose
Glucose molecule exist in two forms.
• Open chain form
• Ring form
Open Chair Form
It is a molecule which are open and unbranched backbone of six carbon atoms,C-1 is a part of Aldehyde group and each of having five hydroxyl group.Aldohexose can account for some of the properties of glucose ,but can not explain in some reaction because it has an aldehyde group.
Figure 4.1-long chain of glucose

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Ring Chain Form
Ring structure also known as CYCLIC CHAIN. open chain also exist in equilibrium with several cyclic isomers , each containing Ring of carbons which is a closed by one oxygen atom .the ring arises from the open chain form by an intramolecular Nucleophilic addition reaction between the aldehyde group and either the C-4 or C-5 hydroxyl group ,forming a HEMIACETAL linkage.

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This cyclic structure can be represented in two forms;
Fischer projection formula
Haworth formula
5.1- Fischer Projection Formula
Emil Fischer devised this projection .According to this ,two dimensional representation of a three dimensional organic molecule by projection. A Fischer projection is used to differentiate between D and L- molecules. In this,penultimate carbon of D sugars are directed towards hydrogen on the left and hydroxyl on the right.L-sugar will be shown with the hydrogen on the right and hydroxyl on the left.
Two mirror images are formed in which there is difference of one point and there is L and D-glucose are formed .they are called Enantiomers. In this there is difference of Carbon -2 which are chiral centre

5.1 -Fischer formula

(Anonymous ,2005,Wikipedia .com)
• In this projection ,all horizantal bonds project toward the viewer, while the vertical bonds project away from the viewer. the orientation of the bonds tells us that they are the ENANTIOMERS.they also in the form of BALL and STICK model.
Figure5.1.2-Dglucose

Anonymous ,2003,Wikipedia.glucose .com

The aldehyde group reacts with an alcohol group on the same sugar to form Hemiacetal
• ? -D -Glycopyranose
• ?-D-Glycopyranose

Figure 5.1.3 -?,?-Glucose

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5.2- Haworth Projection Formula
W.N.Haworth proposed the Haworth projection formula.its projection formula depict the sugar in cyclic forms in which ?-glucose have central oxygen which are donates the lone into C-1 and form a cyclic HEMIACETAL and then change into ?-glucose.
It clearly indicates stereochemical arrangement of groups on ring . the pyranose forms of the sugars are internal hemiacetals formed by the combination of aldehyde and ketone group of sugar with the OH group on the 5 carbon. On the other hand , furanose are formed by the combination of aldehyde or ketone group of sugar with the OH group on the 4 carbon.
One or two optical isomers are differ only in one asymmetric carbon atom.they have same chemical formula but differ only in spatial configuration ,this is called EPIMERS and this process is called EPIMERIZATION.In this D and L-Glucose are epimers which each other. They show epimerization so they are disteriomers.
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Figure 5.2.1-Haworth Formula

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? Pyranose form is More Stable than Furanose
Pyranose is more stable because they are 6-carbon membered ring compound and its bond strength are stable due to its Vander Wal Forces are high. They have more isomers compound in its they have two chair forms, two boat forms, two half chair forms and twisted forms also occur. While in the case of Furanose ,its bond strength are not stable due to weak Vander
Waal forces and its isomers range are half.
Figure5.2.2–D-pyranose
Figure5.2.3-?-glycopyranose
.
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6-Boat and Chair Form
It represents three dimensional configuration of sugar in nature.it have axial and equatorial bond in it.
In CHAIR form there are two planes . the axial position is not parallel to any of the carbon -carbon bonds while the equatorial bond is parallel to one or more of the carbon -carbon bonds.
The BOAT conformation has highest energy of all three conformations .there is also axial and equatorial bond occur .
Figure 6.1-Boat and chair Form

? Bond Conformation
The conformation of bond angle between C-O-C is 111* (hemiacetal).Bond angle between C-C-C is 109* cyclohexane which further divide into chair and boat forms.
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References
Kenji Kamide ,Eleviser (,2005), Cellulose and Cellulose Derivatives.
Anonymous,(1998) Handbook of biodegradable Polymers
Anonymous (2003,2005) http://en.m.wikipedia.org./wiki/glucose
Campbell\Farrell (2003) Biochemistry 4 ed. Retrieved from South Melbourne. Location from English Book.

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