Lactams. XXIII. Thermal cis-trans isomerization of the 5-ethyl-2-oxo-4-piperidineacetic acid system: Effect of an N-substituent

フォーマット:

論文

責任表示:

Fujii, Tozo ; Ohba, Masashi ; Yoshifuji, Shigeyuki ; Akiyama, Shigeaki

言語:

英語

出版情報:

日本薬学会, 1985-03-25

著者名:

• Fujii, Tozo
• Ohba, Masashi
• Yoshifuji, Shigeyuki
• Akiyama, Shigeaki

掲載情報:

Chemical & pharmaceutical bulletin

ISSN:

0009-2363      

巻:

33

通号:

3

開始ページ:

1062

終了ページ:

1068

バージョン:

publisher

概要:

In order to investigate the effect of an N-substituent on thermal cis-trans isomerization of the 5-ethyl-2-oxo-4-piperidineacetic acid system, the N-alkyl analogs (±)-1b, c and (±)-2b, c and the N-(2-arylethyl) analogs (-)-1f, … g, i and (+)-2f, g, i were separately heated neat at 180℃, and the propress of their cis-trans isomerization reactions was followed by determining the isomer ratios in the reaction mixtures according to the previously reported C-13 nuclear magnetic resonance spectroscopic method. It has been found that in all cases the reaction comes to equilibrium within 28-130 min, when the cis and trans isomers exist in a ration of 1 : 2. These results together with those obtained previously with the analogs (±)-1a, d, e, (-)-1h, (±)-2a, d, e, and (+)-2h indicate that a higher and/or bulkier N-substituent tends to decrease the rate of cis-trans isomerization of the 5-ethyl-2-oxo-4-piperidineacetic acid system, which is a useful synthon for the synthesis of benzo-[a] quinolizidine-type Alangium alkaloids. Among the substrates used in the present equilibration study, (±)-1b, c and (±)-2b, c were prepared from the corresponding N-unsubstituted lactam esters (±)-3 and (±)-7 by the"lactim ether method." 続きを見る

URL:

http://hdl.handle.net/2297/7628