Einige Umsetzungen von Inhydrazinen mit Isocyanaten:
[2+2]- und [4+2]Cycloadditionen, (Hydrazinoethinyl)metallierung
Some Reactions of Ynehydrazines with Isocyanates:
[2+2]- and [4+2]Cycloadditions, (Hydrazinoethynyl)metallation Gerhard Himbert, Oliver Gerulat
Fachbereich Chemie der Universität Kaiserslautern, Erwin-Schrödinger-Straße, D-67663 Kaiserslautern, Germany
Sonderdruckanforderungen an Prof. Dr. G. Himbert.
Fax: +49 (0)63 12 05 39 21. E-mail: ghimbert@rhrk.uni-kl.de Herrn Prof. Dr. M. Regitz anlässlich seiner Emeritierung gewidmet Z. Naturforsch.56 b,1196Ð1204 (2001); eingegangen am 2. August 2001 Cycloadditions, Cyclic Betaines, 1,3-Oxazin-4-ones
The (silylethynyl)- and the (tolylethinyl)-hydrazines1aand1breact with aryl isocyanates 2aÐeand arylsulfonyl isocyanates2f,gto form the corresponding substituted 3-arylimino-(or arylsulfonylimino-) 1,1,2-trimethyl-5-oxopyrazolidinium-4-ides3aÐh. The silyl group in the 4-position can be replaced by a hydrogen atom (formation of6aÐe). Heating of6din toluene induced the unequivocal transformation of the betaine to an isomer, the spectrocopic data of which are in concordance with those of the 4-quinolone derivative7. Aroyl isocyanates8 react in a [4+2]cycloaddition with1ato furnish the 1,3-oxazin-4-ones9aandb. The stannyla- ted ynehydrazine1cadds the cumulenic system of an aryl isocyanate (2d) across the Csp-Sn single bond, and trimethylstannylN-(p-chlorophenyl)-3-(trimethylhydrazino)propiolimidate 10is isolated. With two molecules of2dthe hydantoin derivative11is formed.
