Efficient total synthesis of neocryptolepine and synthetic access to 6-methylquinindoline from a common intermediate
A convenient approach toward the indoloquinolines neocryptolepine and 6-methylquinindoline from a common intermediate, is reported. Both sequences, designed for maximum use of accessible reagents and robust conditions, are straightforward and efficient. They involved the amidation of 2-aminobenzalde...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/50447 |
| Acceso en línea: | http://hdl.handle.net/11336/50447 |
| Access Level: | acceso abierto |
| Palabra clave: | NEOCRYPTOLEPINE 6-METHYLQUININDOLINE TOTAL SYNTHESIS HETEROCYCLES https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | A convenient approach toward the indoloquinolines neocryptolepine and 6-methylquinindoline from a common intermediate, is reported. Both sequences, designed for maximum use of accessible reagents and robust conditions, are straightforward and efficient. They involved the amidation of 2-aminobenzaldehyde (prepared by iron-mediated reduction of 2-nitrobenzaldehyde) with 2-nitrophenylacetic acid, followed by a K2CO3-assisted cyclization to form a 3-(2-nitrophenyl)quinolin-2-one as the common precursor. Me2CO3-mediated N-methylation of the lactam, reduction of the nitro moiety and final cyclization resulted in 55% overall yield of neocryptolepine, whereas cyclocondensation and N-methylation afforded 79% overall yield of 6-methyl quinindoline. Thus, the sequences toward the targets entailed two POCl3-promoted C-N bond forming reactions, two Fe-mediated nitro group reductions and two base-promoted transformations. |
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