Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/2199
Título: | Synthesis of novel 6-enaminopurines |
Autor(es): | Carvalho, M. Alice Zaki, M. Proença, M. Fernanda R. P. Booth, Brian L. Álvares, Yolanda |
Palavras-chave: | 6-enaminopurines Imidazoles Ethoxymethylenemalononitrile Ethoxymethylenecyanoacetate 6-methoxyformimidoyl purines Malononitrile |
Data: | 2004 |
Editora: | Royal Society of Chemistry |
Revista: | Organic and Biomolecular Chemistry |
Citação: | "Organic and biomolecular chemistry". 2 (2004) 2340-2345. |
Resumo(s): | Two different approaches have been used for the synthesis of 6-enaminopurines 6 from 5-amino-4-cyanoformimidoyl imidazoles 1. In the first approach imidazoles 1 were reacted with ethoxymethylenemalononitrile or ethoxymethylenecyanoacetate under mild experimental conditions and this led to 9-substituted-6-(1-amino-2,2-dicyanovinyl) purines 6a-f or 9-substituted-6-(1-amino-2-cyano-2-methoxycarbonylvinyl) purines 6g-k. These reactions are postulated to occur through an imidazo-pyrrolidine intermediate 7, which rapidly rearranges to the 6-enaminopurine 6. In the second approach 6-methoxyformimidoyl purines 3, prepared in two efficient steps from 5-amino-4-cyanoformimidoyl imidazoles 1, were reacted with malononitrile and methylcyanoacetate with a mild acid catalysis (ammonium acetate or piperidinium acetate) to give 6-enaminopurines 6a, 6d, 6f, 6g and 6k in very good yields. Only low yields were obtained for the 6-enaminopurine 6j, as competing nucleophilic attack on C-8 of either 3d or 6j causes ring opening with formation of pyrimido-pyrimidines 11 and 10a respectively. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/2199 |
DOI: | 10.1039/b406806h |
ISSN: | 1477-0520 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | CDQuim - Artigos (Papers) |
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displayarticle.pdf | 439,85 kB | Adobe PDF | Ver/Abrir |