`=>` Glucose is an aldohexose and is also known as dextrose.
`=>` It is the monomer of many of the larger carbohydrates, namely starch, cellulose.
`=>` It is probably the most abundant organic compound on earth.
`=>` It was assigned the structure given in fig.1 on the basis of the following evidences :
1. Its molecular formula was found to be `color{red}(C_6H_(12)O_6).`
2. On prolonged heating with `color{red}(HI)`, it forms `color{red}(n)`-hexane, suggesting that all the six carbon atoms are linked in a straight chain. See fig.2.
3. Glucose reacts with hydroxylamine to form an oxime and adds a molecule of hydrogen cyanide to give cyanohydrin. These reactions confirm the presence of a carbonyl group (`color{red}(> C = O)`) in glucose. See fig.3.
4. Glucose gets oxidised to six carbon carboxylic acid (gluconic acid) on reaction with a mild oxidising agent like bromine water. This indicates that the carbonyl group is present as an aldehydic group. See fig.4.
5. Acetylation of glucose with acetic anhydride gives glucose pentaacetate which confirms the presence of five `color{red}(–OH)` groups. Since it exists as a stable compound, five `color{red}(–OH)` groups should be attached to different carbon atoms. See fig.5.
6. On oxidation with nitric acid, glucose as well as gluconic acid both yield a dicarboxylic acid, saccharic acid. This indicates the presence of a primary alcoholic `color{red}((–OH))` group in glucose. See fig.6.
`=>` The exact spatial arrangement of different `color{red}(—OH)` groups was given by Fischer after studying many other properties.
`=>` Its configuration is correctly represented as `color{red}(I)`. So. gluconic acid is represented as `color{red}(II)` and saccharic acid as `color{red}(III)`. See fig.7.
`=>` Glucose is correctly named as `color{red}(D(+))`-glucose. `color{red}(‘D’)` before the name of glucose represents the configuration whereas `color{red}(‘(+)’)` represents dextrorotatory nature of the molecule.
`=>` It may be remembered that `color{red}(‘D’)` and `color{red}(‘L’)` have no relation with the optical activity of the compound. The meaning of `color{red}(D–)` and `color{red}(L–)` notations is given as follows :
● The letters `color{red}(D)` or `color{red}(L)` before the name of any compound indicate the relative configuration of a particular stereoisomer.
● This refers to their relation with a particular isomer of glyceraldehyde.
● Glyceraldehyde contains one asymmetric carbon atom and exists in two enantiomeric forms as shown in fig.8.
● All those compounds which can be chemically correlated to `color{red}((+))` isomer of glyceraldehyde are said to have `color{red}(D-)` configuration whereas those which can be correlated to `color{red}((–))` isomer of glyceraldehyde are said to have `color{red}(L-)`configuration.
● For assigning the configuration of monosaccharides, it is the lowest asymmetric carbon atom (as shown below) which is compared.
● As in `color{red}((+))` glucose, `color{red}(-OH)` on the lowest asymmetric carbon is on the right side which is comparable to `color{red}((+))` glyceraldehyde, so it is assigned `color{red}(D)`-configuration. For this comparison, the structure is written in a way that most oxidised carbon is at the top. See fig.9.
`=>` Glucose is an aldohexose and is also known as dextrose.
`=>` It is the monomer of many of the larger carbohydrates, namely starch, cellulose.
`=>` It is probably the most abundant organic compound on earth.
`=>` It was assigned the structure given in fig.1 on the basis of the following evidences :
1. Its molecular formula was found to be `color{red}(C_6H_(12)O_6).`
2. On prolonged heating with `color{red}(HI)`, it forms `color{red}(n)`-hexane, suggesting that all the six carbon atoms are linked in a straight chain. See fig.2.
3. Glucose reacts with hydroxylamine to form an oxime and adds a molecule of hydrogen cyanide to give cyanohydrin. These reactions confirm the presence of a carbonyl group (`color{red}(> C = O)`) in glucose. See fig.3.
4. Glucose gets oxidised to six carbon carboxylic acid (gluconic acid) on reaction with a mild oxidising agent like bromine water. This indicates that the carbonyl group is present as an aldehydic group. See fig.4.
5. Acetylation of glucose with acetic anhydride gives glucose pentaacetate which confirms the presence of five `color{red}(–OH)` groups. Since it exists as a stable compound, five `color{red}(–OH)` groups should be attached to different carbon atoms. See fig.5.
6. On oxidation with nitric acid, glucose as well as gluconic acid both yield a dicarboxylic acid, saccharic acid. This indicates the presence of a primary alcoholic `color{red}((–OH))` group in glucose. See fig.6.
`=>` The exact spatial arrangement of different `color{red}(—OH)` groups was given by Fischer after studying many other properties.
`=>` Its configuration is correctly represented as `color{red}(I)`. So. gluconic acid is represented as `color{red}(II)` and saccharic acid as `color{red}(III)`. See fig.7.
`=>` Glucose is correctly named as `color{red}(D(+))`-glucose. `color{red}(‘D’)` before the name of glucose represents the configuration whereas `color{red}(‘(+)’)` represents dextrorotatory nature of the molecule.
`=>` It may be remembered that `color{red}(‘D’)` and `color{red}(‘L’)` have no relation with the optical activity of the compound. The meaning of `color{red}(D–)` and `color{red}(L–)` notations is given as follows :
● The letters `color{red}(D)` or `color{red}(L)` before the name of any compound indicate the relative configuration of a particular stereoisomer.
● This refers to their relation with a particular isomer of glyceraldehyde.
● Glyceraldehyde contains one asymmetric carbon atom and exists in two enantiomeric forms as shown in fig.8.
● All those compounds which can be chemically correlated to `color{red}((+))` isomer of glyceraldehyde are said to have `color{red}(D-)` configuration whereas those which can be correlated to `color{red}((–))` isomer of glyceraldehyde are said to have `color{red}(L-)`configuration.
● For assigning the configuration of monosaccharides, it is the lowest asymmetric carbon atom (as shown below) which is compared.
● As in `color{red}((+))` glucose, `color{red}(-OH)` on the lowest asymmetric carbon is on the right side which is comparable to `color{red}((+))` glyceraldehyde, so it is assigned `color{red}(D)`-configuration. For this comparison, the structure is written in a way that most oxidised carbon is at the top. See fig.9.