New route to pyrido[1,2-b]pyridazinium inner salts. Evidence of a 1,3-dipolar cycloaddition-ring expansion process

✍ Scribed by Jesús Valenciano; Ana M. Cuadro; Juan J. Vaquero; Julio Alvarez-Builla

• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 204 KB
• Volume: 40
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(98)02406-x

✦ Synopsis

2-Alkoxyearbonylpyridinium N-aminides behave as 1,3-dipoles when reacted with Michael aeeeptors, giving rise to the corresponding cycloadducts which, depending on their regioisomeric nature, subsequently undergo a ring expansion to give pyrido[1,2-b]pyridazinium inner salts.