• Title/Summary/Keyword: Dichloroketene cycloadduct

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Tropolone 類에 關한 硏究 (II) ${\beta}$-Methyltropolone의 合成과 그 ${\gamma}$-異性體 (Studies on Tropolones (Ⅱ) ${\beta}$-Methyltropolone Synthesis and Its ${\gamma}$-Isomer)

  • 심재후
    • 대한화학회지
    • /
    • 제13권1호
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    • pp.83-88
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    • 1969

  • By the three-step synthesis of alkyltropolone from five-membered cyclopentadiene, as described in Part Ⅰ, methyltropolone has been prepared. From the hydrolysis product of dichloroketene-methylcyclopentadiene cycloadduct, ${\beta}$-(Ⅰ) and ${\gamma}$-methyltropolone (Ⅱ) were separated, with the first predominating, by means of repeated fractional recrystallization and fractional vacuum sublimation. The total yield of these methyltropolones in the hydrolysis step was about 40%. Comparison of this result with those obtained in part Ⅰ revealed the following order as the relative readiness of their preparation: tropolone > methyltropolone > ethyltropolone. The reason for formation of the isomeric (Ⅱ) was discussed by an interpretation of NMR spectrum of cycloadduct in the unsaturation and methylgroup region.

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