Sandbox 1A2: Difference between revisions
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Shown in the box to the right is an animation of the cyclization of D-glucose to form D-glucopyranose. The electron-withdrawing oxygen atom of the carbonyl group carries a permanent positive dipole while the alcohol group bound to the penultimate carbon acts as a nucleophile due to the two lone pairs of electrons around the oxygen atom. Starting from its linear form, glucose begins to cyclize with the 90 degree rotation of the bond between C4 and C5. The glucose molecule is now configured in a way that the "tail" of glucose is close to the "head" of glucose. The nucleophilic group on the penultimate carbon is then able to undergo an intramolecular reaction with the carbonyl group of the aldehyde. Free rotation around the first carbon and second carbon allows for the formation of 2 anomers - alpha-D-glucopyranose & beta-D-glucopyranose. The specific anomer is decided by the position of the -OH group of the anomeric carbon; and the anomeric carbon can always be spotted by finding the carbon that is attached to two oxygens. | Shown in the box to the right is an animation of the cyclization of D-glucose to form D-glucopyranose. The electron-withdrawing oxygen atom of the carbonyl group carries a permanent positive dipole while the alcohol group bound to the penultimate carbon acts as a nucleophile due to the two lone pairs of electrons around the oxygen atom. Starting from its linear form, glucose begins to cyclize with the 90 degree rotation of the bond between C4 and C5. The glucose molecule is now configured in a way that the "tail" of glucose is close to the "head" of glucose. The nucleophilic group on the penultimate carbon is then able to undergo an intramolecular reaction with the carbonyl group of the aldehyde. The hydrogen atom from the alcohol (in white) can also be seen leaving the alcohol and attaching to the oxygen that was originally an aldehyde, now making it an alcohol. Free rotation around the first carbon and second carbon allows for the formation of 2 anomers - alpha-D-glucopyranose & beta-D-glucopyranose. The specific anomer is decided by the position of the -OH group of the anomeric carbon; and the anomeric carbon can always be spotted by finding the carbon that is attached to two oxygens. | ||
Revision as of 00:52, 10 December 2014
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Shown in the box to the right is an animation of the cyclization of D-glucose to form D-glucopyranose. The electron-withdrawing oxygen atom of the carbonyl group carries a permanent positive dipole while the alcohol group bound to the penultimate carbon acts as a nucleophile due to the two lone pairs of electrons around the oxygen atom. Starting from its linear form, glucose begins to cyclize with the 90 degree rotation of the bond between C4 and C5. The glucose molecule is now configured in a way that the "tail" of glucose is close to the "head" of glucose. The nucleophilic group on the penultimate carbon is then able to undergo an intramolecular reaction with the carbonyl group of the aldehyde. The hydrogen atom from the alcohol (in white) can also be seen leaving the alcohol and attaching to the oxygen that was originally an aldehyde, now making it an alcohol. Free rotation around the first carbon and second carbon allows for the formation of 2 anomers - alpha-D-glucopyranose & beta-D-glucopyranose. The specific anomer is decided by the position of the -OH group of the anomeric carbon; and the anomeric carbon can always be spotted by finding the carbon that is attached to two oxygens.