15  US 7,495,101 B2  16  *  *  *  *  *  21.  The process according to claim  1,  wherein the tempera› ture at which the acylation is effected is from about 70°  C. to  about 90°  C.  20.  The process according to claim  1,  wherein the amount  of carboxylic acid anhydride employed for the acylation is  from about 1.1 to about 1.5 equivalents per equivalent of the  methylpyrido[3,4-e] [1 ,3]dioxepin-9-ol to be acylated.  drous acid is added for the rearrangement of the Diels-Alder  adduct is from about 70°  C. to about 90°  C. 