cyclohexanedicarboxylic anhydride was added under acidic conditions for reaction for 11 hours and 0 51 g of anhydride was added under basic conditions for reaction for 12 hours the resultant was collected under acidic conditions obtaining 0 26 g 68 yield mf2a 1 the resultant was heated at220 u00b0 c under reduced pressure for 5 hours and then the progress of imidization was observed by ir mf2b 1 86 mg of the resultant was taken and reacted with 0 24 g of 3 5 dimethylphenyl isocyanate in a dehydrated pyridine at 80 u00b0 c 21 hours later 0 23 g of isocyanate was further added the progress of the reaction was confirmed by ir after 27 hours and a methanol insoluble part was collected but the reaction nonuniformly progressed to the end the resultant was stirred and washed in dmso obtaining 62 mg 37 yield of insoluble part mf2c 1 since the reaction might not progress completely 0 24 mg of a newly dried n 1 2 cyclohexanedicarbonyl chitosan was swollen in 0 75 ml of dma then 65 mg of licl 0 4 ml of pyridine and 0 21 g of isocyanate were added and reacted for 20 hours then 0 22 g of isocyanate was newly added but the reaction nonuniformly progressed then 4 hours later the resultant was collected as a methanol insoluble part and 21 mg 40 of the reaction product was obtained mf2c 2 a chitosan derivative was produced according to the above reaction formula first the reaction was performed as shown in the scheme of the following method 1 0 36 g of maleic anhydride was added to 0 21 g of chitosan under acidic conditions for reaction for 12 hours and then 0 35 g of anhydride was.