Alkylation des «malonyl‐α‐aminopyridines»

Urban, R.; Grosjean, Mireille; Arnold, Wolf

doi:10.1002/hlca.19700530505

Cited by 13 publications

(2 citation statements)

References 8 publications

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“…The mesoionic form 1a was subsequently confirmed by 1 H NMR measurements, although the resonance of the interesting "mesoionic" proton on 1-N was not observed. 4 We have located this signal at 12.04 ppm in DMSOd 6 solution. Simonsen confirmed the mesoionic structure 1a in the solid state by X-ray crystallography.…”

Section: Introductionmentioning

confidence: 93%

Mesoionic pyridopyrimidinylium and pyridooxazinylium olates and non-mesoionic pyridopyrimidinones. Structures in the solid state, solution, and matrices †

Plüg¹,

Wallfisch²,

Andersen³

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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Section: Introductionmentioning

confidence: 93%

Mesoionic pyridopyrimidinylium and pyridooxazinylium olates and non-mesoionic pyridopyrimidinones. Structures in the solid state, solution, and matrices †

Plüg¹,

Wallfisch²,

Andersen³

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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“…Mesoionic compounds often appear as colored materials and their spectroscopic properties have been explored for applications such as pigments, liquid-crystalline copolymers, or photosensitive components . 3-Aryl mesoionic pyrido[1,2- a ]pyrimidinones show a characteristic yellow color, with long wavelength absorption maximum between 300 and 450 nm in the UV/vis spectra . When exposed outdoors, such compounds absorb sunlight with the potential to decompose.…”

Section: Mesoionic Pyrido[12-a]pyrimidinonesmentioning

confidence: 99%

Mesoionic Pyrido[1,2-a]pyrimidinone Insecticides: From Discovery to Triflumezopyrim and Dicloromezotiaz

Zhang

2017

Acc. Chem. Res.

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One of the greatest global challenges is to feed the ever-increasing world population. The agrochemical tools growers currently utilize are also under continuous pressure, due to a number of factors that contribute to the loss of existing products. Mesoionic pyrido[1,2-a]pyrimidinones are an unusual yet very intriguing class of compounds. Known for several decades, this class of compounds had not been systemically studied until we started our insecticide discovery program. This Account provides an overview of the efforts on mesoionic pyrido[1,2-a]pyridinone insecticide discovery, beginning from the initial high throughput screen (HTS) discovery to ultimate identification of triflumezopyrim (4, DuPont Pyraxalt) and dicloromezotiaz (5) for commercialization as novel insecticides. Mesoionic pyrido[1,2-a]pyrimidinones with a n-propyl group at the 1-position, such as compound 1, were initially isolated as undesired byproducts from reactions for a fungicide discovery program at DuPont Crop Protection. Such compounds showed interesting insecticidal activity in a follow-up screen and against an expanded insect species list. The area became an insecticide hit for exploration and then a lead area for optimization. At the lead optimization stage, variations at three regions of compound 1, i.e., side-chain (n-propyl group), substituents on the 3-phenyl group, and substitutions on the pyrido- moiety, were explored with many analogues prepared and evaluated. Breakthrough discoveries included replacing the n-propyl group with a 2,2,2-trifluoroethyl group to generate compound 2, and then with a 2-chlorothiazol-5-ylmethyl group to form compound 3. 3 possesses potent insecticidal activity not only against a group of hopper species, including corn planthopper (Peregrinus maidis (Ashmead), CPH) and potato leafhopper (Empoasca fabae (Harris), PLH), as well as two key rice hopper species, namely, brown planthopper (Nilaparvata lugens (Stål), BPH) and rice green leafhopper (Nephotettix virescens (Distant), GLH), but also against representative lepidoptera species Diamondback moth (Plutella xylostella (Linnaeus), DBM) and fall armyworm (Spodoptera frugiperda (J.E. Smith), FAW). Further optimization based on 3 led to discovery of triflumezopyrim (4), with a 5-pyrimidinylmethyl group, as a potent hopper insecticide for rice usage. Optimization of the substituents on the pyrido- moiety of 3 resulted in discovery of dicloromezotiaz (5) as a lepidoptera insecticide. In this Account, we present the discovery and optimization of mesoionic pyrido[1,2-a]pyrimidinone insecticides toward the identification of triflumezopyrim (4) and dicloromezotiaz (5). We hope that knowledge and lessons derived from this discovery program will provide valuable information for future agrochemical and drug discovery. Our successful discovery and commercialization development of two novel insecticides based on meosoionic pyrido[1,2-a]pyridiminones may also stimulate interests of scientists from other disciplines to adopt this uncommon yet intriguing heterocycle ring...

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