Patent ID: 7015247

Claim:
A compound having the formula: wherein R 9 is an acyl group of an acid having at least 3 carbon atoms, the acid being selected from the group consisting of alkenoic acids having 1 to 6 ethylenic double bonds, phenoxyalkanoic acids, ring halogenated phenoxyalkanoic acids having 1 to 3 ring halogen atoms, alkylidene bis-phenoxyalkanoic acids and alkylidene bis-ring halogenated phenoxyalkanoic acids having 1 to 3 ring halogen atoms in each ring; R 10 is hydrogen, an alkyl group having 1 to 4 carbon atoms, or an acyl group having 1 to 4 carbon atoms; each R 11 , R 12 , and R 13 is an alkyl group having 1 to 4 carbon atoms, or a pharmaceutically acceptable salt thereof.