Triazene derivatives of (1,x)diazacycloalkanes.Part VI.3-({5,5-Dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)-4,4-dimethyl-1-[2-aryI-1-diazenyl]imidazolidines - Synthesis,characterization,and X-ray crystal structure

摘要

Reaction of a series of diazonium salts with a mixture of formaldehyde and 1,2-diamino-2-methylpropane affords the 3-({5,5-dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)-4,4-dimethyl-1-[2-aryl-1-diazenyl]imidazolidines (1a-1f) in excellent yield.The products have been characterized by IR and NMR spectroscopic analysis,elemental analysis,and X-ray crystallography.The X-ray crystal structure of the p-methoxycarbonyl derivative (1c) establishes without question the connectivity of these novel molecules,which can be described as linear bicyclic oligomers with two imidazolidinyl groups linked together by a one-carbon spacer.This is indeed a rare molecular building block.The molecular structure is corroborated by ~1H and ~(13)C NMR data,which correlates with the previously published data of compounds of types 5 and 6 derived from 1,3-propanediamine.The triazene moieties in the crystal of 1c display significant pi conjugation,which gives the N-N bond a significant degree of double-bond character.This in turn causes restricted rotation around the N-N bond,which leads to considerable broadening of signals in both the ~1H and ~(13)C NMR spectra.The molecular ion of the p-cyanophenyl derivative (1b) was observed using electrospray mass spectrom-etry (ES + Na).The mechanism of formation of molecules of type 1 is proposed to involve diazonium ion trapping of the previously unreported bisimidazolidinyl methane (13).