Abstract: An endoscope system includes a memory configured to be able to store a parameter set which is a combination of parameters associated with various processes during an endoscope inspection and set for each user, the memory being able to store a number of parameter sets corresponding to a plurality of user accounts, a touch panel configured to selectively display a display screen made up of a plurality of layers and a control section configured to cause the touch panel to display a user setting selection list for calling the parameter set for each user stored in the memory for part of a display region of a main screen that classifies and displays functions with high use frequency during the endoscope inspection.

Abstract: An optically active cyanohydrin represented by the following general formula (1): ##STR1## wherein each of R1 and R2 is a hydrogen atom or an amino-protecting group, and the configurations relating to the carbon atoms at the *2-position and *3-position are as follows: in the case of the carbon atom at the *2-position being in R-configuration, the carbon atom at the *3-position is in S-configuration, and in the case of the carbon atom at the *2-position being in S-configuration, the carbon atom at the *3-position is in R-configuration, can be efficiently produced by crystallizing one of the optically active cyanohydrins while treating a mixture of cyanohydrin diastereomers in the presence of an amine and an organic solvent to change the configuration relating to the carbon atom at the 2-position and thereby cause isomerization.