Carbon-13 Nuclear Magnetic Resonance Spectroscopy of Some Synthetic Pyrethroids and Their Related Compounds

Epoxychrysanthemates: two-dimensional NMR analyses and stereochemical assignments

“…Our assignments for the vinyl methyl (C9 and C10) and the cyclopropylmethyl (C5 and C6) carbons for Ph differ from literature reports (Janes, 1977; ) but are consistent with predictions based on steric compression (Nakazawa et al, 1980). In all cases, C9 is crowded relative to C10 and is expected to resonate at higher field.…”

“…and 13C NMR studies of pyrethroids with natural trons-chrysanthemic acid and synthetic cts-chrysanthemic acid moieties are important for structural, stereochemical, and conformational analyses (Bramwell et al, 1969;Crombieetal.,1975;Iwaokaetal., 1981;Janes, 1977;Krishnamurthy and ; Nakazawa et al, 1980). In these papers, there are some contradictory assignments involving the pairs of resonances for the cyclopropyl and vinyl gem-dimethyl groups.…”

Synthesis and Larvicidal Properties of Some Cyclopropylcarboxamides Related tocis-Permethrin

“…Primary carbons of C-4 (15-16 ppm) and C-5 (28-29 ppm) were also readily assigned because of the shielding effect of the amide carbonyl group. In the 13 C NMR spectra of related cis-pyrethroid esters (Crombie et al, 1975;Janes, 1977;Nakazawa et al, 1980;Bertok et al, 1996), C-2 was upfield compared to C-6. In the 1 H NMR spectra of 3-29, the doublet for the proton at C-2 (near 2 ppm) and the doublet of doublets for the proton at C-6 (1.7 ppm) were easily identified.…”