| 摘要 |
NEW MATERIAL:A compound of formula I (R<1> and R<2> are lower alkyl). USE:An insecticide and acaricide. PREPARATION:A carbazinic acid ester, e.g. methyl 3-(2,2-dimethylchroman-8-yl)- carbazinate, is reacted with phosgene in a solvent, e.g. toluene, at -20-+150 deg.C to give a compound of formula III, e.g. methyl 3-(chlorocarbonyl)-3-(2,2-dimethylchroman-8-yl)-carbazinate, which in then cyclized in the presence of a base, e.g. triethylamine, at -20-+150 deg.C to afford the aimed compound of formula I .
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