Boron-containing small molecules for controlling ectoparasites

A compound having a structure of formula I or II:

• wherein
• A is
• where * is bonded to the carbonyl;
• Y is hydrogen, fluoro, chloro, or bromo;
• R1 is phenyl substituted 2-4 times, said substitutions comprising i) 1-4 substitutions with the same or different of halo, and 0-1 substitutions with methyl, difluoromethyl, trifluoromethyl, methoxy, trifluoromethoxy, or trifluoroethoxy, or ii) 2 trifluoromethyl groups;
• R2 is methyl, fluoromethyl, trifluoromethyl, or perfluoroethyl;
• R3a and R3b are independently selected from hydrogen, methyl, ethyl, fluoromethyl, or R3a and R3b combine with the carbon to which they are attached to form a cyclopentyl ring or a cyclohexyl ring;
• Z is —CH2—, —CH2—CH2—, —CH(CH3)—, or —C(CH3)2—;
• and
• R6 is hydrogen or methyl;
• or a salt thereof.