Molecules 2012, 17(12), 13879-13890; doi:10.3390/molecules171213879
Article

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

Motoko Akita, Hideyuki Seto, Reiko Aoyama, Junko Kimura and Keiji Kobayashi* email
Graduate School of Science, Josai University, Sakado, Saitama 350-0295, Japan
* Author to whom correspondence should be addressed.
Received: 8 October 2012; in revised form: 31 October 2012 / Accepted: 20 November 2012 / Published: 22 November 2012
(This article belongs to the Special Issue Spiro Compounds)
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Abstract: 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.
Keywords: spiro-N,N-ketals; perimidine; diazapleiadiene; prototropic tautomerism; X-ray structure determination

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MDPI and ACS Style

Akita, M.; Seto, H.; Aoyama, R.; Kimura, J.; Kobayashi, K. Novel Rearrangements in the Reactions Directed Toward Preparation of Spiro-N,N-ketals: Reactions of Naphthalene-1,8-diamine with Ninhydrin and Isatin. Molecules 2012, 17, 13879-13890.

AMA Style

Akita M, Seto H, Aoyama R, Kimura J, Kobayashi K. Novel Rearrangements in the Reactions Directed Toward Preparation of Spiro-N,N-ketals: Reactions of Naphthalene-1,8-diamine with Ninhydrin and Isatin. Molecules. 2012; 17(12):13879-13890.

Chicago/Turabian Style

Akita, Motoko; Seto, Hideyuki; Aoyama, Reiko; Kimura, Junko; Kobayashi, Keiji. 2012. "Novel Rearrangements in the Reactions Directed Toward Preparation of Spiro-N,N-ketals: Reactions of Naphthalene-1,8-diamine with Ninhydrin and Isatin." Molecules 17, no. 12: 13879-13890.

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