Patent ID: 7108896

Claim:
A method of increasing a helical twisting power HTP (1/μm) HTP =1/( P ×0.01 C ) where C represents an amount (% by weight) of an optically active compound and P represents a natural pitch (μm) in a compound having a partial structure represented by the formula (A): wherein * represents the position of an asymmetric carbon atom, which has an asymmetric carbon atom, said method comprising replacing a partial structure represented by the above formula (A) by a partial structure represented by the formula (B): wherein * represents the position of an asymmetric carbon atom, and Y 1 represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group or an isothiocyanate group, the alkyl group or the alkenyl group is not substituted or can have one, or two or more fluorine atoms, chlorine atoms, cyano groups, methyl groups or trifluoromethyl groups as a substituent, and one, or two or more methylene groups existing in the alkyl group or the alkenyl group may be substituted with —CO— or may be substituted with an oxygen atom or —COO— in such a manner that oxygen atoms are not directly bonded to each other.