1H-4,5,6,7-tetrahydro-1,3-diazepines. Part I: Synthesis, spectral and chemical properties of 1,2-diaryl derivatives

摘要

The synthesis of several 1,2-diaryl-1H-4,5,6,7-tetrahydro- 1,3-diazepines 1 by cyclization of N-aryl-N'- benzoyltetramethylenediamines 2 is described. Two alternative synthetic routes to obtain precursors 2 are discussed, being that which employes pyrrolidine as starting material the most convenient. Nucleophilic attack of compounds I on methyl iodide affords 1,2-diaryl-1H-4,5,6,7-tetrahydro-1,3-diazepinium iodides 3. H-1-nmr spectra of these compounds are unequivocally assigned by means of NOESY experiments. H-1-nmr spectra of compounds 1 and 3 are analyzed and compared inter se and with those of compounds 1 run in the presence of trifluoroacetic acid-d. Reduction of compounds 1 with borane leads regiospecifically to N-aralkyl-N'-aryltetramethylenediamines 7. [References: 29]