Synthesis and characterization of 1-aza-4-oxa-7-thiacyclononane: A novel azacrown heterocycle

The heterocycle 1-aza-4-oxa-7-thiacyclononane ([9]aneNOS, 5) was prepared from the intermediate N-p-toluenesulfonyl-1-aza-4-oxa-7-thiacyclononane (3) upon its deprotection via Na/Hg amalgam. The byproduct, N,N′-bis-(p-tolylsulfonyl)-1,13-diaza-7,16-dioxa-4,10-dithiacylododecane (4), was also isolated from the pot mixture of 3. Compound 5 was characterized by ¹H and ¹³C NMR, and IR spectroscopy. Compounds 3 and 4 were characterized by ¹H and ¹³C NMR, and IR spectroscopy, elemental analysis, and X-ray crystallography. The reaction of 5 with Ni(BF₄)₂·6 H₂O in methanol produced the sandwich complex ([9]aneNOS)₂Ni(BF₄)₂, 6, which was characterized by UV-visible and IR spectroscopy, elemental analysis, and X-ray crystallography.