A multipurpose chemical modification of cellulose to yield soluble cellulose derivatives was investigated on the basis of (i) O-acylation of the parent cellulose using N-Boc-protected Gly, ${alpha}Ala$, and ${eta}Ala$, and subsequent Boc-removal, (ii) N-acylation of amino acid-modified cellulose in homogenous solution reaction system using Boc-oligopeptides with multiple types of the side-chain functionalities, and (iii) N-acylation of ${eta}Ala$-Cellulose using 10 kinds of simple Boc-oligopeptides. As for the (i), Thermochemical computation to estimate ${Delta}G$ transition was well coincided with the observed yields in O-acylations. In the case of (ii), beside the similar ${Delta}G$-schemes, a strain energy profile, which is coupled with the preferred conformer transition of the amino acid-modified cellulose, was involved to rule out the N-acylation. The symmetric anhydrate in the N-acylating agents in the (iii) are tend to be in torsions due to the ${eta}$-strand-like steric stabilizations in the peptides, resulting in the highest N-acylation yields as much as 98 %.