A NOVEL GEMINAL DIOL AS A HIGHLY SPECIFIC AND STABLE IN-VIVO INHIBITOR OF INSECT JUVENILE-HORMONE ESTERASE

Thio-containing and acetylenic trifluoromethyl ketones were potent inh ibitors of insect juvenile hormone (IH) esterase with greater inhibito ry activity than aliphatic and alpha,beta-unsaturated homologs. Octylt hio-1,1, 1 -trifluoropropan-2-one was the most potent inhibitor with t he greatest equilibrium hydration constant in pure water. However, a k eto/hydrate equilibrium was not necessary for JH esterase inhibition. The carbonyl tautomer of 1-octyl [1 -(3,3,3-trifluoropropan-2,2-dihydr oxy)] sulfone (OTPdOH-sulfone) was not detectable, and yet OTPdOH-sulf one was a potent in vitro inhibitor of IH esterase with an I-50 Of 1.2 nM. The mechanism of JH esterase inhibition by these compounds is dis cussed. OTPdOH-sulfone inhibited JH esterase with minimal activity tow ard insect l-naphthyl acetate esterase and electric eel acetylcholines terase. The inhibitor was also active in vivo, selective for JH estera se, and persistent for over 32 h. OTPdOH-sulfone when topically applie d to larval and adult cabbage loopers, Trichoplusia ni, elicited juven oid activity apparently because of the specific in vivo inhibition of JH metabolism. (C) 1997 Wiley-Liss, Inc.