Dinotefuran (MTI-446: (RS)-1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine) is a new neonicotinoid commercialized by Mitsui Chemicals. Research led to this novel neonicotinoid by the removal of the chloropyridine or chlorothiazole ring that had been considered as indispensable for neonicotinoides. The research advanced as follows; (1) selection of acetylcholine for the lead compound, (2) recognition of the insecticidal advantages of 3-methoxypropyl compounds, (3) synthesis of (+/-)-tetrahydro-3-furylmethyl compounds by cyclization of the 3-methoxypropyl moiety. It resulted in dinotefuran which has a (+/-)-tetrahydro-3-furylmethyl moiety instead of a halogenated aromatic heterocyclic ring, and belongs to the third-generation neonicotinoids (sub-class: furanicotinyl compounds).
The potassium alkoxide (3) of tert-butyldimethylsilyl ether of ethylene glycol successfully initiated a living polymerization of ethylene oxide to a controlled degree of polymerization with a narrow distribution. End-capping with p-vinylbenzyl chloride and methacryloyl chloride, followed by desilylation with tetra-n-butylammonium fluoride afforded the corresponding &>-hydroxypoly(ethylene oxide) macromonomers (la and 2a). The radical copolymerization of the macromonomers with styrene and their homopolymerization in benzene have revealed reactivities similar to those of the corresponding -methoxy derivatives. Micellar polymerization in water, however, occurred more rapidly to give an apparently simpler, starlike polymer with a number of hydrophilic, polyethylene oxide) arms with -hydroxy end groups.Research from the Ministry of Education, Science and Culture, Japan. We are greatly indebted to Shinetsu Chemical Co., Ltd., for tert-butyldimethylsilyl chloride.
ABSTRACT:Poly(ethylene oxide) macromonomers carrying p-vinylbenyl and methacrylate end-groups were prepared by the anionic polymerization of ethylene oxide followed by reactions withp-vinylbenzyl chloride and methacryloyl chloride, respectively. Radical copolymerization with styrene (M1) in tetrahydrofuran at 60°C was carried out to give the macromonomer's relative reactivity (ljr1), which decreased by a factor as much as about 1/2 with increasing degree of polymerization to about 100. This is discussed in terms of the kinetic excluded volume effect but by taking into consideration the generally repulsive interaction between different polymer chains and/or some different solution behavior of the polymers. These should be important factors in copolymerization involving the macromonomer.KEY WORDS Macromonomer I Poly( ethylene oxide)/ Monomer Reactivity Ratio I Polymer Effect on Reactivity I Kinetic Excluded Volume Effect I Polymer-Polymer Interaction / unreacted macromonomers. Recent developments in macromonomer ('macromer') techniques have made possible the preparation of a variety of graft copolymers of well-defined structure, as reviewed
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