SUMMARY: To check the possibility of living polymerization with a biscyclopentadienyl metallocene, propylene polymerization was conducted by Cp 2 ZrMe 2 at -78 8C or Cp 2 HfMe 2 at -50 8C using B(C 6 F 5 ) 3 and AlOct 3 as a cocatalyst. The polymer yield increased linearly with polymerization time. The polypropylene obtained showed narrow molecular weight distribution (M -w /M -n 1.04 -1.15). In addition, the number-average molecular weight increased in proportion to the polymerization time. It was, thus, found that living polymerization of propylene proceeds with the catalyst systems at a very low temperature. Isospecific living polymerization of 1-hexene also proceeded with the rac-(et)Ind 2 ZrMe 2 catalyst at -78 8C.
Dimethyl 9,10-dihydro-9,10-dioxobenzo[/]quinoline-2,4-dicarboxylate (4) was synthesized, and its physical and chemical properties were compared to those of the trimethyl ester of PQQ (PQQTME,2) and the 1-methyl derivative (3). The synthesis of 4 was accomplished by a Doebner-von Miller-type annulation between 3-amino-2-naphthol and dimethyl 2-oxoglutaconate and a subsequent oxidation with Fremy's salt. The electronic effect of the pyrrole nucleus of coenzyme PQQ (1) was examined by comparing the reactivity of 4 to that of 2 and 3 in the acetone adduct formation reaction, the redox reaction with phenylhydrazine, and the aerobic autorecycling oxidation of benzylamine. The significant role of the pyrrole nucleus in conducting the intramolecular general base catalysis in the amine oxidation is discussed.
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