* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
Synthesis Example 2 Crosslinking agent compound 2 (CL-02) represented by the following chemical formula (1-B) was synthesized in the same manner as the production method of synthesis example 1, except that 9,9-bis(4-hydroxyphenyl)fluorene of 3.5 g (10 mmol) was used as the bisphenol compound. As a result, a white compound of 3.9 g was obtained. Crosslinking agent compound 3 (CL-03) which is 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane represented by the following chemical formula (1-C), was obtained from Asahi Organic Chemicals Industry Co., Ltd.: