Glucosamine derivatives for the prevention or treatment of joint disorders

A compound of Formula (II), or a pharmaceutically acceptable salt or ester thereof:

• where:
• R1 is hydrogen, substituted alkyl, or acyl group derived from a carboxylic acid, or a peptide, optionally with a protecting group, a phosphonyl group, or a sulfonyl group;
• R2 is hydrogen, acyl, or alkyl;
• R3, R4, and R5 are independently hydrogen, substituted or unsubstituted alkyl, aryl, arylalkyl, alkylaryl, cyclic or heterocyclic moiety, or acyl group derived from a carboxylic acid, an amino acid, or a peptide, optionally with a protecting group, a phosphonyl group, or a sulfonyl group, provided that R3, R4, and R5 are not all acyl group at the same time, wherein when R5 is acyl group which is a carbonyl group that is attached through its carbon atom to an alkyl group, the alkyl group is methyl, ethyl, propyl, butyl, hexyl, isopropyl, tert-butyl, sec-butyl, isobutyl, cyclopropyl, cyclopentyl or cyclohexyl;
• and
• n is an integer from 1 to 6;
• provided that R1, R3, R4, and R5 are not all hydrogen at the same time;
• or
• one or more of R1, R3, R4, and R5 are independently selected from alkoxycarbonyl, aryloxycarbonyl, and arylalkoxycarbonyl;
• or
• R3 and R4, taken together with the atoms to which they are attached, form a substituted or unsubstituted heterocyclic ring.