Synthesis and insecticidal properties of ether analogues of DDT‐pyrethroids

Holan, G.; Johnson, Wynona M.; Jarvis, Karen E.; Virgona, Christopher T.; Walser, R.

doi:10.1002/ps.2780170615

Cited by 7 publications

(1 citation statement)

References 8 publications

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“…Sequential α-arylation, reduction, and nucleophilic substitution reactions gave 20 in 87% overall yield (Fig. 6b) 45 . Likewise, preparation of compound 21 , an analog of the commercial pain medication named Demerol 46 , illustrated one value of the α-arylation of an azetidine.…”

Section: Resultsmentioning

confidence: 99%

Palladium-catalyzed α-arylation for the addition of small rings to aromatic compounds

Hartwig

2019

Nat Commun

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Small, strained rings have rigid, defined conformations and unique electronic properties. For these reasons, many groups seek to use these subunits to form biologically active molecules. We report a generally applicable approach to attach small rings to a wide range of aromatic compounds by palladium-catalyzed α-arylation of cyclopropyl, cyclobutyl and azetidinyl esters. The direct α-arylation of cyclopropyl esters and cyclobutyl esters is achieved in high yield by ensuring that the rate of coupling exceeds the rate of Claisen condensation. The α-arylation of azetidines is achieved without ring opening of the strained saturated heterocycle by conducting the reactions with an azetidine derivative bearing a benzyl protecting group on nitrogen. Mechanistic studies show that the α-arylation of small rings is challenging because of the weak acidity of α C-H bond (cyclopropanes), strong sensitivity of the strained esters to Claisen condensation (cyclobutatanes), or facile decomposition of the enolates (azetidinyl esters).

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Section: Resultsmentioning

confidence: 99%

Palladium-catalyzed α-arylation for the addition of small rings to aromatic compounds

Hartwig

2019

Nat Commun

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The pyrethrins and related compounds. Part XXXIII. Effective combinations in the gemdimethyl‐central group region of non‐ester pyrethroids

et al. 1988

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Synthesis and testing for insecticidal activity ofa wide range of combinations representing simultaneous variation in the acid or alcohol and central ffagments of non-ester pyrethroids reveals strong interactions between these changes, When the gemdimethyl (--CMe,--), or the equivalent cyclopropyl, group is present in the central chain rather than in a side chain, a new set of requirements for effective central groups applies; those identified as conferring highest activity in this situation are -CH=CH .CH,--; -(CH2)3-; --CH2C0 .CH2-and -CH20 .CH2-. Other variations establish the limits to structural changes within these combinations, for activity to be retained.

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The pyrethrins and related compounds. Part XXXIV. Optimisation of insecticidal activity in non‐esters

Baydar¹,

Elliott²,

Farnham³

et al. 1988

Pestic. Sci.

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Optimisation of activity within the structural constraints defined by the preceding work, by varying the substituents on phenyl in the acid fiagment (10 variations), the nature of the group fuIfilling the dimethyl function (three variations), the central linking group (four variations) and the presence or absence of a If-jluoro substituent in the alcohol fragment, has led to achiral compounds as active as bioresmethrin against houseflies and mustard beetles. Statistical analysis of the eflects has shown that particular combinations, for instance the cyclopropyl form of dimethyl with a central E-alkene group (but not a central ether group), lead to higher activity than expected. I-Fluoro substitution enhances activity more strongly against mustard beetles. DiJuorocyclopropyl compounds are on average slightly more active than cyclopropyl analogues.

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Synthesis and insecticidal properties of ether analogues of DDT‐pyrethroids

Cited by 7 publications

References 8 publications

Palladium-catalyzed α-arylation for the addition of small rings to aromatic compounds

Palladium-catalyzed α-arylation for the addition of small rings to aromatic compounds

The pyrethrins and related compounds. Part XXXIII. Effective combinations in the gemdimethyl‐central group region of non‐ester pyrethroids

The pyrethrins and related compounds. Part XXXIV. Optimisation of insecticidal activity in non‐esters

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