Synthesis of 2-aryl-1,2,3,4-tetrahydroquinazolin-1-ols and their conversion to 7-aryl-9H-6-oxa-5,8-diaza-benzocycloheptenes


Coskun N. , Cetin M.

TETRAHEDRON LETTERS, vol.45, no.49, pp.8973-8975, 2004 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 45 Issue: 49
  • Publication Date: 2004
  • Doi Number: 10.1016/j.tetlet.2004.10.062
  • Title of Journal : TETRAHEDRON LETTERS
  • Page Numbers: pp.8973-8975

Abstract

2-Aminobenzylamine was reacted with corresponding aromatic or heteroaromatic aldehydes to give 1,2,3,4-tetrahydroquinazolines 1 the oxidation of which with H2O2-tungstate in methanol led to the formation of the corresponding 1,2,3,4-tetrahydroquinazolin-1-ols 2. A one-pot procedure involving the treatment of the in situ formed quinazoline 1 with H2O-tungstate again led to the formation of 2. Compounds 2 react with 2equiv of aryl isocyanate in toluene at room temperature to produce compounds 3. The probable mechanism of the ring-expanding carbamoylation of quinazolin-1-ols 2 to 6-oxa-5,8-diaza-benzocycloheptenes 3 is discussed. (C) 2004 Elsevier Ltd. All rights reserved.