ORGANIC CHEMISTRY 354

THE CYCLIC STRUCTURE OF GLUCOSE

MONOSACCHARIDES

(+)-GLUCOSE IS AN ALDEHYDE.

ALDEHYDES FORM ACETALS!

C₆H₁₂O₆ + CH₃OH, DRY HCl --> C₇H₁₄O₆

FROM THE FORMULA IT APPEARS TO BE A HEMIACETAL.

BEHAVES LIKE AN ACETAL, STABLE IN BASE.

FORMS TWO DIFFERENT CRYSTALS WITH DIFFERENT MELTING POINTS AND ANGLE OF ROTATION.

(+)-GLUCOSE FORMS TWO DIFFERENT CRYSTALS.

a: MP = 146^o, ROTATION = +112^o

b: MP = 150^o, ROTATION = +18.7^o

BOTH a and b CHANGE TO +52.6^o; CALL PROCESS MUTAROTATION.

C₇H₁₄O₆ + (CH₃)₂SO₄ --> C₁₁H₂₂O₆ (ONLY 4 OH's REACTED)!

C₁₁H₂₂O₆ + HCl, H₂O --> C₁₀H₂₀O₆ (ONLY 1 CH₃ CAME OFF)!

a AND b D-GLUCOSE

COMMON MONSACCHARIDES.

REDUCING SUGAR

REDUCES TOLLENS' AND FEHLING'S SOLUTIONS

GLUCOSE, MANNOSE, GALACTOSE AND FRUCTOSE ARE REDUCING SUGARS

HOW CAN FRUCTOSE, A KETOSE, BE A REDUCING SUGAR?

REACT WITH PHENYLHYDRAZINE

GLUCOSE, MANNOSE, AND FRUCTOSE GIVE THE SAME OSAZONE

CYCLIC HEMIACETALS

HAWORTH PROJECTION

GLYCOSIDES

AMINO SUGARS

OXIDIZED AND REDUCED FORMS

PENTOSES, ETC.