Novel Rearrangements in the Reactions Directed Toward Preparation of Spiro-N,N-ketals: Reactions of Naphthalene-1,8-diamine with Ninhydrin and Isatin

Molecules

Motoko Akita¹  Hideyuki Seto¹  Reiko Aoyama¹  Junko Kimura¹ 

[1] id="af1-molecules-17-13879">Graduate School of Science, Josai University, Sakado, Saitama 350-0295, Jap

关键词: spiro-N;    N-ketals;    perimidine;    diazapleiadiene;    prototropic tautomerism;    X-ray structure determination;   

DOI  :  10.3390/molecules171213879

来源: mdpi

【 摘 要 】

Spiro-N,N-ketal 5, consisting of a phthaloperine heterocyclic ring and a naphtha[1,8-ef][1,4]diazepine ring, was obtained along with spiro-N,N-ketal 2 via 2,2-condensation in the reaction of ninhydrin with naphthalene-1,8-diamine. Their molecular structures were elucidated by X-ray crystal structural analysis. Aside from these spiro compounds, the diazapleiadiene compound 3 formed by 1,2-condensation and the 1,4-isoquinolinedione compound 4 arising from ring expansion were isolated. When isatin was reacted with naphthalene-1,8-diamine, spiro-N,N-ketal 6 and the two 1H-perimidine-based compounds 7 and 8 were isolated. Compound 8 was revealed to undergo a fast dynamic prototropic tautomerization in solution. Plausible mechanisms of the formation of the products are proposed.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.