           
                                                                       
    CH—C—－OH＋H－—O—CHCH   ——→                  CH—C—O—CHCH＋HO
               ‖                                       H＋                   ‖
                O                                                                                              O
                                                                                                                   
                                            —                           
CH—C—O—CHCHCHCHCHCHCHCH
           ‖
            O                                    
                                             
CHOHCHC—O—CHCH
                ‖
                 O            
                                      
         O
         \ /
O—C    CH
 |      ‖
OH   O
                
               10  17    