74  US 8,637,222 B2  73  Derivative [HM-1] having a structure shown below. The  purity was 92% (as determined by a liquid chromatography  method).  Gram of Hydroxymethyl  Group-Containing Phenol  Derivative [HM-1] obtained in Synthesis Example above was  added to 1 liter of methanol and dissolved with stirring under  heating. Subsequently, 1 ml of concentrated sulfuric acid was  added to the resulting solution, and the mixture was refluxed  under heating for 12 hours. After the completion ofreaction,  the reaction solution was cooled, and 2 g of potassium car› bonate was added thereto. This mixture was sufficiently con› centrated, and 300 ml of ethyl acetate was added thereto. The  resulting solution was washed with water and then concen› trated to dryness to obtain 22 g of a white solid ofMethoxym› ethyl Group-Containing Phenol Derivative [MM-1] having a  structure shown below. The purity thereof was 90% ( as deter- mined by a liquid chromatography method).  Synthesis of(MM-1):  Furthermore, the phenol derivatives shown below were  synthesized in the same manner.  [HM-2]  CH20H  CH20H  HO  OH  HOH2C  CH20H  OH  [MM-1]  OH  OH  ’---o  [MM-4]  OH  0/  HO  H3COH2C  HO  [MM-3]  CH20CH3  OH  CH20CH3  CH20CH3  HO  HOH2C  HO  [HM-3]  OH  CH20H  OH  HO  [MM-2]  CH20CH3  OH  -continued 