... Tetrahedron Letters. Volume 24, Issue 44, 1983, Pages 4789–4792. Cover image Cover image. A novel approach towards the synthesis of the 3,4,5-trihydro-1,3-diazepin-5-ol ring structure. ... Ann Arbor, Michigan 48104 USA. Received 10 May 1983, Available online 2 April 2001. Abstract.