Important plants

TLS Online TPP Program

#Id: 7853

#XL - T Zoology

Thus, D glucose in aqueous solution exists as an equilibrium mixture of 5 compounds. The pyranose form predominates in solution.

aD glucofuranose (0.5%)

aD-glucopyranose (37%)

aldehydo- -glucose (0.003%)

bD-glucofuranose (0.5%)

bD-glucopyranose (62%)

TLS Online TPP Program

#Id: 7852

#XL - T Zoology

The pyranose forms of the sugars are more stable than the furanose forms in solution.

TLS Online TPP Program

#Id: 7850

#XL - T Zoology

The 6-membered cyclic form of sugars is usually called the “pyranose” form in reference to the cyclic ether pyran.

TLS Online TPP Program

#Id: 7849

#XL - T Zoology

The pyranose form of glucose dominates (>99%) at equilibrium in aqueous solution

TLS Online TPP Program

#Id: 7847

#XL - T Zoology

The two diastereomers of glucose in its "pyranose" form are called the alpha (a) and beta (B) isomers, which differ in the orientation of the OH at C-1

TLS Online TPP Program

#Id: 7846

#XL - T Zoology

When the anomeric hydroxyl of a D-hexose is on the same side of the ring as C-6, the structure is β a by definition; when it is on the opposite side from C-6, the structure is α.