ChemInform Abstract: Synthesis and Dimroth Rearrangement of 6-Cyano-1,2,4-triazolo[4,3-a]pyrimidin-5- and 7-ones. A Novel Alkylation with Orthoesters and a New Participation of the Cyano Group in the Rearrangement.

✍ Scribed by E. S. H. EL ASHRY; Y. EL KILANY; N. RASHED; A. MOUSAAD; H. ASSAFIR

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 37 KB
• Volume: 30
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199908164

✦ Synopsis

Synthesis and Dimroth Rearrangement of 6-Cyano-1,2,4-triazolo[4,3a]pyrimidin-5-and 7-ones. A Novel Alkylation with Orthoesters and a New Participation of the Cyano Group in the Rearrangement. -Formic acid and triethyl orthoformate react with 2-hydrazinopyrimidin-4-ones (I) and (VI) to furnish triazolo[4,3-a]pyrimidinones (III) and (VII) respectively. Dimroth rearrangement of (III), (VII), and related (X) with 2% ethanolic KOH gives triazolo[1,5-a]pyrimidinones [cf. (IV), (VIII), and (XI)]. Use of 10% ethanolic KOH leads to a novel participation of the cyano group in the rearrangement [→ (V)].