MONOSACCHARIDE DERIVATIVES

They are modified monosaccharides.

GLYCOSIDES

• They are compounds formed by condensation reaction between a sugar and hydroxyl group of another substance which may be a sugar, a sterol, glycerol, methyl alcohol, etc.
• Streptomycin is a glycoside.
• Other medicinally important ones are cardiac glycosides.

ALCOHOLIC SUGAR

• When aldehyde group of monosaccharide is converted into alcohol (OH) group, then it is called alcoholic sugar.
• Glucose → Sorbitol
• Mannose → Mannitol
• Reduction of aldehyde and ketone group converts a sugar into sugar alcohol.
• Ascorbic acid or vitamin C is sugar acid.
• Glucouronic acid and iduronic acid are components of chondroitin sulphate, cell wall and gums.

AMINO SUGARS (HEXOSAMINES)

• When -OH group of second carbon converted into -NH then it is called amino sugar.
• Glucose → Glucosamine
• They are generally formed by replacement of hydroxyl group at carbon 2 with amino group (-NH ).
• Glucosamine is the most common amino sugar that occurs in chitin, fungal wall and hyaluronic acid.
• Galactosamine is used in synthesis of cartilage.
• Mannosamine is found in mucoprotein.
• Amino sugars also occur in some antibiotics.