HETEROCYCLES

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact: purchase@heterocycles.com

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

■ Synthesis and Reactions of 1,3,4-Selenadiazines

Wolf-Diethard Pfeiffer,* Harald Roßberg, Nazken Kelzhanova, Amanzhan T. Saginayev, Alexander Villinger, and Peter Langer*

*Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany

Abstract

Various 1,3,4-selenadiazines were prepared by cyclization of selenosemicarbazides with phenacyl bromides. The compounds generally exist in their 6H-tautomeric form and contain an exocyclic imino group in the solid state. 1,3,4-4H-Selenadiazines, available from 1,2-dimethylated selenosemicarbazides, cannot be isolated because they rapidly undergo a deselenation reaction under the conditions of their formation. Deselenation can be induced for 1,3,4-6H-selenadiazines under forcing conditions by reflux of a solution in glacial acetic acid. On the other hand, a ring contraction is observed when concentrated HCl or HBr is used.