Pyridine ring formation by the reaction of conjugated carbodiimides with enamines

Pyridine ring formation by the reaction of conjugated carbodiimides with enamines

Creators Nishida Akio

Creators Isomura Yuji

Creators Noguchi Michihiko

The reaction of N-[6-methyl-2-oxo-4(2H)-pyranyl]-substituted carbodiimides 3, generated by the treatment of [6-methyl-2-oxo-4(2H)-pyranyl] iminotriphenylphosphorane (1) with isocyanates 2 in situ, with 1-(1-pyrrolidinyl) cyclopentene (4) in refluxing toluene or dioxane gave cyclopenta [d] pyrano [4,3-b] pyridine derivatives 5. A similar reaction of 3 with 1-(1-pyrrolidinyl) cyclohexene (6) afforded pyrano [4,3-b] isoquinoline derivatives 7 and 8. Compound 8 corresponds formally to the adduct of 7 and isocyanate 2.

[ISSN]0386-3433

[NCID]AA0086073X