drous acid is added for the rearrangement of the Diels-Alder adduct 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. 

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. 

* * * * * 

