A newly synthesized juvenile hormone active cornpound, S-311S3 (2-[1-methyl-2-(tl-phenoxyphenoxy)ethoxy]pyridine) xvas evaluated for its inhibition of emergence of adult Culex PiPiens Pattens, AnoPheles stePhensi, Aedes aegyPti and Musca domestica in the Iaboratory. It was more active than methoprene, diflubenzuron, or temephos against last instar larvae of Cx. p. pallens, An. stephensi and Ae. aegypti. S-31183 was n]ore active than methoprene and diflubenziiron a.craitist 4-day-old larvae of Af. donzestica in the artificial medium, and inore active than rnethoprene against e.crgs and 4-day-old larvae of A4. domestica in the chicken manure medium.

Cycloaddition reactions of the titled compound 1 with dienes, 1,3-dipoles, and heterocumulenes have been investigated in order to study the origin of its peri-, stereo-, and regioselectivities. Both dienes 4-6 and 1,3-dipoles 12-15 reacted with 1 to give Diels-Alder adducts 7-9 and 1,3-dipolar cycloadducts 1619, respectively, in good yields. In these reactions, 1 reacted only at the endocyclic double bond and the exocyclic double bond remained unchanged. In contrast, 1 reacted with dichloroketone at both its endocyclic and exocyclic double bonds to give 20 (27%) and anti-21 (18%), syn-22 (13%), respectively. The similar but increased stereoselectivity was observed in the similar reaction of dihydro compound 2, and two adducts anti-28 (40%) and syn-29 (13%) were obtained. The reaction of 1 with chlorosulfonyl isocyanate (CSI) took place in a stereospecific fashion to give the syn adduct 30a (69%) which was converted to the @-lactam 30b (95%) and dihydro derivative 31 (72%) by succesive dechlorosulfonylation and catalytic hydrogenation. The stereoselectivity was dramatically changed in the similar reaction of 2, which after dechlorosulfonylation gave adducts 34 (90%) and 35 (6.8%). The structures of adducts were determined on the basis of spectroscopic data, chemical conversions, and X-ray diffraction analyses.From the viewpoint of synthetic usefulness and theoretical interest, 7-isopropylidenebenzonorbornadiene (1) and its derivatives have received considerable attention in the past few year^.^-^' The unique electronic structure is known to affect their chemical reactivities. The energetic proximity of its highest occupied (HOMO) and lowest unoccupied molecular orbitals (LUMO) enables 1 to perform both HOMO-controlled and LUMO-controlled reaction^,^^*^^ depending on the situation. In the Diels-Alder reaction, 1 showed as a dienophile a significant rate increase ~ ~

No abstract

No abstract