Estudo das reações da monotosil-hidrazona de furila e compostos analogos na presença de alumina basica

AUTOR(ES)
DATA DE PUBLICAÇÃO

1989

RESUMO

The reactions of benzi1 monotosylhydrazone in basic medium and of 2-diazo-1,2-diphenyl-1-ethanone in neutral mediun with the nucleophiles hydrazineand benzoylhydrazine yielded the products (Ph2)CHCO-NH-NH-COR (48, R = -CH(Ph)2 e 49, R = -Ph) which result from the reaction of the nucleophile with the intermediate diphenylketene formed by the Wolff rearrangement. With these results it was verified that benzil monotosy- lhydrazone and 2-diazo-1,2-diphenyl-1-ethanone react through the same intermediate, the diphenylketene, formed by thermal decomposition of the 2-diazo-1,2-diphenyl-1-ethanone and that this was the actual reagent formed "in situ" in basic conditions. Considering the above results and the probable instability of 2-diazo-1,2-difuryl-1-ethanone, we started studies with furilmonotosylhydrazone in basic mediun to form this a-diazoketone "in situ" and to intercept the probable decomposition intermediates with several nucleophilic reagents. The reactions of furil monotosylhydrazone with the nucleophiles phenylhydrazine and p-nitrophenylhydrazine yielded the azo compounds. Fu-CH=C(Fu)N=N-C6H4-R(51, R= -H e 52, R= - NO2), as a result of the ketocarbene intercption, where the nucleophilic attack ocurred at the eletrophilic carbene center. On the other hand, the reactions of furil monotosylhydrazone with the nucleophiles methylamine, benzylamine and n-butylamine yielded five-membered cyclic vinilogous imides which probably result from reaction with the g,d-acetylenic a,b -olefinic aldehyde formed from ring opening of the furan ring adjacent to the carbene center of the keto-carbene intermediate. The nucleophilic attack ocurred at the aldeyde and at the g position. The reaction with hydrazine yielded an analogous six-membered ring product.

ASSUNTO(S)

alumina

ACESSO AO ARTIGO

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