Chitosan was modified to give N-1-naphthylmethylenechitosan (d.s. 0.92
, 1), which was tritylated to give N-(1-naphthylmethylene)-6-O-tritylc
hitosan (d.s. 0.97 for trityl, 2). Compound 2 was acylated to give a s
eries of 3-O-acyl derivatives (d.s. 0.24-1.0, 4-14), and was treated w
ith 2-D, L-chloropropionic acid to give 3-O-(1-D, L-carboxyethyl) deri
vative (d.s. 0.37, 15). Compound 15 was treated in aqueous 1 N HCl to
give 3-O-(1-D, L-carboxyethyl) chitosan (d.s. 0.37, 16, muraminan). Co
mpound 2 was treated with 2-D, L-halopropionic acids in sodium methyls
ulfinylcarbanion to give 3-O-(1-D, L-carboxyethyl)-N, N-(-1-D, L-dicar
boxyethyl)-O-tritylchitosan (d.s. 2.9 for carboxyethyl, 17). Compound
17 was treated with HCl in methanol to afford 3-O-(1-carboxyethyl)-N,
N-(1-dicarboxyethyl) chitosan (d.s. 2.4 for carboxyethyl, 18). Compoun
ds 16 and 18 were soluble in water. Copyright (C) 1996 Elsevier Scienc
e Ltd