Title: Gentiobiose
CAS Registry Number: 554-91-6
CAS Name: 6-O-b-D-Glucopyranosyl-D-glucose
Additional Names: 6-(b-D-glucosido)-D-glucose; amygdalose
Molecular Formula: C12H22O11
Molecular Weight: 342.30
Percent Composition: C 42.11%, H 6.48%, O 51.41%
Literature References: From gentianose by partial hydrolysis with 0.2% H2SO4 or with invertin. From D-glucose by enzymatic synthesis with emulsin: Helferich, Lette, Org. Synth. 22, 53 (1942). Prepn and structure: Haworth, Wylam, J. Chem. Soc. 123, 3120 (1923); Hudson, J. Am. Chem. Soc. 51, 1708 (1930). Structure: Hassid, Ballou in W. Pigman, The Carbohydrates (Academic Press, New York, 1957) p 492. Synthesis: Helferich, Klein, Ann. 450, 219 (1926); Reynolds, Evans, J. Am. Chem. Soc. 60, 2559 (1938). Hydrolysis with almond emulsin gives 2 mols D-glucose.
Derivative Type: a-Form
Properties: Lentil-shaped crystals with 2CH3OH from methanol. Bitter taste. Very hygroscopic. mp 86°. Shows mutarotation. [a]D22 +16° (3 min) ® +8.3° (3½ hrs c = 4). Sol in water, hot methanol, hot 90% alcohol.
Melting point: mp 86°
Optical Rotation: [a]D22 +16° (3 min) ® +8.3° (3½ hrs c = 4)
Derivative Type: b-Form
Properties: Anhydr crystals from alc, mp 190-195°. Shows mutarotation. [a]D22 -5.9° (6 min) ® +9.6° (6 hrs, c = 3). Sol in water, hot methanol, hot 90% alcohol.
Melting point: mp 190-195°
Optical Rotation: [a]D22 -5.9° (6 min) ® +9.6° (6 hrs, c = 3)
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