ピロリジン誘導体の合成研究 (第1報)
2-Decarboxykainic Acidの合成
1965 年 85 巻 2 号 p. 130-142
詳細
1965 年 85 巻 2 号 p. 130-142
Utilizing the alkali ring opening reaction of 2-methyl-2-mesyloxymethylcyclopentanone by Eschenmoser, N-benzyl-2-decarboxykainic acid (XXIX) was synthesized, following to the synthetic process shown in Charts 1-C and 2. Steric configuration of 3-and 4-position of pyrrolidine ring was considered to be cis-form as α-kainic acid type. Methylation of XVII afforded 10% of XIX, subordinately, besides usual methyl derivatives (XVIII), and the once produced XVIII was considered to be transformed to XIX in the mechanism illustrated in Chart 3. From the intermediate mentioned above, pyrrolidine derivatives of XXXI, XXXIV, XXXV, XXXVII and XLI were synthesized. The compound (XXXIX), obtained in this reaction, showed the signal of ring methylene in nuclear magnetic resonance spectrum by splitting, in spite of cis-junction, and, on the contrary, singlet was appeared at τ=8.49 in cis form of 5-and 6-membered dual ring system of XLII. This is explained that the ring bond is so rigid that ring inversion becomes difficult in the cis form of 5-and 5-membered ring system.
