Synthesis of 3,5-dihalogeno-2H-1,4-oxazin-2-ones from cyanohydrines

✍ Scribed by L. Meerpoel; G. Hoornaert

• Book ID: 104229349
• Publisher: Elsevier Science
• Year: 1989
• Tongue: French
• Weight: 199 KB
• Volume: 30
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)99196-2

✦ Synopsis

The title compounds 4 were obtained on treatment of qanohydrines 3 of aliphatic and aryl aldehydes with oxalyl chloride or bromide in chlorobenzene at 9&C. Evidence for their structure is given by their spectroscopic data and by the Diels Alder reaction of 4a and & with acetylenic dienaphiles to yield substituted pyridines. Cycloaddition was also observed with ethene.

In previous work' we investigated the reaction be&veer@-aminonitriles 1 and oxalyl chloride in 1,2dichlorobenzene at SO-100°C; they gave &substituted 3,5-dichloro-2(1H)-pyrazinones 2 in good yield.

Now we wish to describe a comparative synthetic method for 3,.5-dihalogeno-2H-l,4-oxazin-2-ones 5

starting from the appropriate cyanohydrines 3. and oxalyl chloride or bromide. Synthetic methods for 2H-1,4oxazin-2-ones are scarcely described in the literature2. Furthermore their access needs several steps, which