Synthesis and mosquito repellent properties of some 2‐alkyl‐<i>N</i>‐acetyloxazolidines

Taylor, Wesley G.; Schreck, C. E.

doi:10.1002/ps.2780330102

Cited by 6 publications

(1 citation statement)

References 6 publications

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“…During studies on the insect repellent properties of oxazolidine heterocycles (1)(2)(3), various N-acetyl and N-alkylcarbonyl derivatives with alkyl or alkenyl groups at C-2 were found to exist in deuterochloroform solution as binary mixtures of rotational isomers (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

An investigation of the rotational isomers of N-acetyl-2,2-dimethyloxazolidine and related compounds by nuclear magnetic resonance spectroscopy and molecular mechanics

Taylor¹,

Hall²,

Schreck³

1992

Can. J. Chem.

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. Can. J. Chem. 70, 165 (1992). The 15 2,2-dimethyloxazolidines described here were found to exist in solution predominantly as a single rotational isomer, unlike N-acetyloxazolidine (I), N-acetyl-2-methyloxazolidine (2), N-acetyl-2-(n-octyl)oxazolidine (3), and other known 2-substituted N-acyloxazolidines. Using ')c NMR spectroscopy, activation energies for interconversion of the E (minor) and Z (major) rotational isomers of 1-3 were determined from coalescence temperature measurements in pyridine-d,. A sample of N-acetyl-2,2-dimethyloxazolidine (4) was isolated for comparison. The rotational isomer of 4 was found by two-dimensional nuclear Overhauser effect spectroscopy (NOESY) to possess the Z (or trans) stereochemistry. Molecular mechanics (MMX) calculations on the E and Z isomers of 1-4 helped to account for these findings. The conformation of the energy-minimized structures resembled a C-5 envelope. Samples of N-aroyl-2,2-dimethyloxazolidines (5a-5n) were isolated and the rotational isomers were assigned the Z stereochemistry by NOESY and ')c NMR experiments. Most of these 2,2-dimethyloxazolidines were ineffective in a bioassay for mosquito repellent activity. Cchantillons des N-aroyl-2,2-dimkthyloxazolidines (5a-5n) et, sur la base d'expkriences de RMN du I3c et de NEOSY, on a attribuC la sttrCochimie Z a leurs isombres rotationnels. La plupart de ces 2,2-dimCthyloxazolidines ne se sont pas avkrkes efficaces lors d'essais biologiques destinCs a mesurer leur activitk comme agent de rCpulsion des moustiques.

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Section: Introductionmentioning

confidence: 99%

An investigation of the rotational isomers of N-acetyl-2,2-dimethyloxazolidine and related compounds by nuclear magnetic resonance spectroscopy and molecular mechanics

Taylor¹,

Hall²,

Schreck³

1992

Can. J. Chem.

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Synthesis and Mosquito Repellent Properties of 2,2-Dialkyl- and 2-Alkyl-4,4-dimethyl-N-acetyloxazolidines

1996

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Nineteen novel N-acetyl-2,2-dialkyloxazolidines (2) and N-acetyl-2-alkyl-4,4-dimethyloxazolidines (3) were synthesized from commercially available carbonyl compounds and ethanolamine or 2-amino-2-methyl-I-propanol. Their bioactivity against laboratory-reared mosquitoes was compared in patch tests to known N-acetyl-2-alkyloxazolidines (1) and N,N-diethyl-m-toluamide (deet insect repellent). Isomeric composition measurements by ["ClNMR spectroscopy favoured the Z rotational isomer for samples of 2 (91-96% Z) and the E rotational isomer for samples of 3 (66-71% E), in agreement with molecular mechanics calculations on rotational isomers of model oxazolidines. Samples of 1 were previously shown to exist in solution mostly as the Z isomer (60-70% Z). Within the optimal molecular weight range for these experimental chemicals, the duration of repellency against Aedes aegypti (L.), Anopheles quadrimaculatus Say and Anopheles albimanus Wiedemann generally followed the order: 1 > 2 > deet > 3. Bioassay data are discussed in relation to the equilibrium populations of rotational isomers for substituted N-acetyloxazolidines.

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Repellents

Carlson

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Repellents, the first line of defense that can be readily used as personal protection, affect insects by disrupting their natural behavior of bloodseeking through biting of humans and animals. The best overall repellent, effective against many species of pest mosquitoes but not all malaria mosquitoes, is N,N ‐diethyl‐ m ‐toluamide (DEET). Commercial products containing DEET are available which are reasonably comfortable for the user and can protect against pests for hours before retreatment on skin. Clothing treatment has become more popular for mosquito protection, using DEET or synthetic pyrethroids. A few compounds, including two cyclohexyl carboxamides, are under development and may eventually replace DEET in the U.S. military system. A 1993 database search showed 27 active ingredients in 212 EPA‐registered products as repellents or feeding depressants. Repellents including DEET are effective, as are synthetic pyrethroids when treated onto clothing to intoxicate ticks. Chemical cockroach repellents are available, but newer compounds are also under development. Methyl anthranilate, a grape‐flavored food additive, is an effective bird repellent when tested against geese, ducks, and gulls; methiocarb is an insecticide that repels birds from food crops; 4‐aminopyridine is a repellent–toxicant that is lethal when used in baits. No consistently repellent compounds are known for deer, however, thiram is registered in Georgia, and Chaperone is registered with EPA for use against deer and rabbits.

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Synthesis and mosquito repellent properties of some 2‐alkyl‐N‐acetyloxazolidines

Cited by 6 publications

References 6 publications

An investigation of the rotational isomers of N-acetyl-2,2-dimethyloxazolidine and related compounds by nuclear magnetic resonance spectroscopy and molecular mechanics

An investigation of the rotational isomers of N-acetyl-2,2-dimethyloxazolidine and related compounds by nuclear magnetic resonance spectroscopy and molecular mechanics

Synthesis and Mosquito Repellent Properties of 2,2-Dialkyl- and 2-Alkyl-4,4-dimethyl-N-acetyloxazolidines

Repellents

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