Dipolar cycloadditions of imidazoline 3-oxides with N-arylmaleimides. Synthesis and diethylamine induced ring-opening of exo and endo hexahydro-7-oxa-2,5,6a-triaza-cyclopenta[a]pentalene-1,3-diones

Coskun N., Mert H., Arikan N.

TETRAHEDRON, cilt.62, sa.7, ss.1351-1359, 2006 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 62 Sayı: 7
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1016/j.tet.2005.11.038
  • Dergi Adı: TETRAHEDRON
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1351-1359
  • Anahtar Kelimeler: cyclic nitrone, 1,3-dipolar cycloaddition, 3-imidazoline 3-oxides, sec-amine induced ring-opening, 3-imidazoline, 1,3-DIPOLAR CYCLOADDITION, DIASTEREOSELECTIVE ADDITION, ARYL ISOCYANATES, REGIO, REACTIVITY, NITRONE, IMIDES
  • Bursa Uludağ Üniversitesi Adresli: Evet

Özet

14-Diarylimidazoline 3-oxides react with N-arylmaleimides in benzene to give predominantly the corresponding endo adducts. Chiral imidazoline 3-oxides react diastereospecifically (cis configuration of the tetrahydroimidazo ring) and diastereoselectively to give cis-endo adducts. The effects of substituents on the aromatic ring of the maleimide was investigated. The presence of electron-withdrawing or releasing group,; have minor effect on the total yields but more pronounced is the effect on the ratio of exo and endo diastereomers. The adducts undergo an interesting and unprecedented ring-opening in the presence of secondary amines to give deoxygenated 3-imidazoline 3-oxides instead of the expected double cis elimination products. Tertiary amines did not induce any reaction, (c) 2005 Elsevier Ltd. All rights reserved.