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Microwave-assisted cyclizations promoted by polyphosphoric acid esters: a general method for 1-aryl-2-iminoazacycloalkanes
The first general procedure for the synthesis of 5 to 7-membered 1-aryl-2-iminoazacycloalkanes is presented, by microwave-assisted ring closure of ω-arylaminonitriles promoted by polyphosphoric acid (PPA) esters. 1-Aryl-2-iminopyrrolidines were easily prepared from the acyclic precursors employing a...
| Autores principales: | , , |
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| Formato: | Online Artículo Texto |
| Lenguaje: | English |
| Publicado: |
Beilstein-Institut
2016
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| Materias: | |
| Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5082496/ https://www.ncbi.nlm.nih.gov/pubmed/27829907 http://dx.doi.org/10.3762/bjoc.12.190 |
| Sumario: | The first general procedure for the synthesis of 5 to 7-membered 1-aryl-2-iminoazacycloalkanes is presented, by microwave-assisted ring closure of ω-arylaminonitriles promoted by polyphosphoric acid (PPA) esters. 1-Aryl-2-iminopyrrolidines were easily prepared from the acyclic precursors employing a chloroformic solution of ethyl polyphosphate (PPE). The use of trimethylsilyl polyphosphate (PPSE) in solvent-free conditions allowed for the synthesis of 1-aryl-2-iminopiperidines and hitherto unreported 1-aryl-2-iminoazepanes. The cyclization reaction involves good to high yields and short reaction times, and represents a novel application of PPA esters in heterocyclic synthesis. |
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