The present invention relates to a device for adjusting the width of a paper web at a rotary lithographic press and the object of the present invention is to prevent ink or specks of paper from becoming attached to contact parts of a pressing member so as to contaminate the surface of the paper web, and to enable straightforward fitting and removing of a rotatable pressing member. In particular, the nonaqueous electrolyte comprises a compound of chemical formula 1 as an electrolyte additive:NC\u2014n-A-m\u2014CN\u2003\u20031wherein, R1 and R2 represent, respectively, alkylene groups, n and m represent integers of 1 to 10, and A is an aromatic hydrocarbon in which the number of carbons is 5 to 9 or O. More specifically, described herein are methods for synthesizing Salinosporamide A and its analogs that includes forming a compound of formula.